Flying in snow

[hoverbover]

Dear All

What experiences does anyone have flying in snow/freezing conditions?

What I really would like to know are the DO's and DONTs obviously things like visibility,recirculation white out in the hover are some problems which can be expanded on but my main concern is are there temperatures and snow types you avoid flying in.
I have done some flying in snow but would appreciate anyones experiences (good and bad)so that hopefully I can learn some more.

Obviously flight into known icing is a definite no go.

I hope someone can enlighten me !!!!!

Regards
hoverbover

PS
Most of my flying is in the UK.

[PurplePitot]

hoverbover - We don't know what you fly so it's a little tricky giving any advice. I can only advise that if you haven't been given any specific training in this field then don't do it - It's a very quick way to get dead......

[hoverbover]

PurplePitot
Its a NOTAR.
I understand your wise words, but its difficult to get specific training in the UK as it doesn't snow that much! Any ideas??

Regards
hoverbover

[Thomas coupling]

Surely your flight manual will tell you the limits?
If you aren't famil with those, try these:

Do not fly in visible moisture below 0 degrees, is good karma for MOST civvy pilots. Due to the venturi effect at the engine intakes (Po) this drops further causing freezing and the engines could cut out!
The same for snow. Don't fly in snow below 0 degrees due to icing. Down to this is ok provided you MONITOR the "stickability"...i.e. if it is building fast and obscuring your view or building too much near the intake(s) then vacate the area. NORMALLY this only becomes a problem when the viz drops to <500m.
White out can wipe you out within seconds. IF you have to land in fresh snow, then adopt a zero / zero technique landing. This keeps you inside the snow vortices for the min amount of time. Don't practice Z/Z's for the first time in snow!!!!
Same goes for the takeoff.

Happy Christmas..


Edited due to some absolute b****cks I printed earlier!
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Thermal runaway.

[This message has been edited by Thomas coupling (edited 06 March 2001).]

[nomdeplume]

TC
Please would you explain zero/zero.
Thanks

[Thomas coupling]

Zero airspeed / zero rate of descent...all coming together at the same time and place! It tends to be 'positive arrival' compared to pussy footing about in the hover prior to touchdown. Take off: pull take off pwr and rotate immediately...in that order!!

Problems: If you don't know what the surface is like (depth etc) then because of the positive landing, there is a risk you may sink thru the light surface and damage the undercarriage. If you try and lighten the touchdown by pulling some power...you'll white out!
Take off: If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!

Fun and games....


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Thermal runaway.

[nomdeplume]

Thanks TC.

[knxhyy]

Hoverbover,

I had a recent experience in snow / icing conditions last weekend which nearly cost me an R22.

Following a training flight with a student i departed the airfield to return home. Due to poor visabilty (1km) / snow showers i decided to land the aircraft in a field and wait for the snow showers to clear.

The snow did not clear and i abandoned the helicopter. The ground was very soft and boggy.

I returned to the helicopter the following morning with a student, the conditions clear blue sky minus 5 degrees prefect flying conditions. Whilst walking to the aircraft i was explaining the dangers of dymanic rollover.

We arrived at the aircraft and as i suspected the aircraft skids were frozen to the ground. We stamped the ground down both sides of the skids to free the aircraft from the ground. We preceeded with the normal preflight check / start up. We are now at full power and ready to lift, the aircraft became light on its skids and i inputed left and right yaw pedals to slide the aircraft from side to side to free the landing gear from the ground. I made a special point of yawing the aircraft to free it from the ground having flown serveral weeks in the Swiss / French Alps and experinced this several times previously. We are now light on the skids and looking outside the student at the controls whist i followed through he continued raising the lever within a split second the aircraft lifted on the passenger side and possibly the front part of the landing gear to the pilots side. The aircraft almost went over i dumped the lever and shut down the aircraft. After exiting the aircraft it became apparent that whilst shuffling on the ground i had in fact shuffled the rear spade part of the landing gear under the very soft suface (Crisp and hard on the surface very soft below)preventing the aircraft from lifting.

Very close call. I will be extremely cautious in future

Any simular occurences?

[Hughes500]

You will find in the 520 manual ( plus other 500 variants ) you may fly in falling snow providing you have the following. No centre seat pax ( never been able to work this out or find anyone who knows - anyone enlighten me ? ); autorelight on and armed, I would suggest that anti ice is on as the temp will be below 5 degrees and you certainly have visible moisture.

Other points, as you will have cabin heat and anti ice on watch your TOT espically if you are heavy. TOT starts to rise the inlet may becoming blocked - unlikely but possible.

Heed everyone else's advice get someone to show you

What Notar do you fly in UK, presumably a 600 as there are no 520 in UK I think ???

[ditchy]

I think no centre seat front passenger might be to keep C of G more rearward.500 has a problem in snow[especially wet snow] that it can build up on the top of the perspex then break off going through the compressor in a big chunk. A lot of weight in front would givea more nose down attitude.I personally have had this happen and on one occasion over a large densely wooded area had 3 flameouts in ten minutes,relit each time by the auto relight.Problem exacerbated by the fact that in these conditions of heavy wet snow speed is back around 60 knots because of the vis and also you will be at a low altitude for the same reason.
I would guess that the no centre seat pax rule is an attempt by the manufacturer to address this problem.Its a while since I flew a 500 and I don't recall any similar restriction was in the 500D manual, but the problem was well known to those of us flying it in winter. I'm only guessing the reason its there for a 520.

[Randy_g]

With a passenger in the centre seat, you may not be able to reach and open the auxiliary air inlet, should the particle sep become blocked with ice/snow. I don't believe it has anything to do with CofG. I've had it flame-out & relight while in straight and level while slinging. The a/c was no more nosedown than in normal flight.

If you do want to fly in falling snow, get ahold of a proper snow deflector. That way there's no flameout problems.

Make absolute sure that your skids are clear, and free from the ground before you start up. With an R22 take hold of the T/R gearbox, and pull down. It should go down with reasonable ease. Our engineer said that the force needed to lift the skids will not harm the tailboom or it's attachment. The same goes for the 500 series. Pull down on the tail, until both skids squat, then lift it back up.

If you don't have experience in snow that is deeper than ankle deep, I recommend you get instruction (try a holiday to Canada, or Switzerland where they get snow)!!! It is very easy to put the a/c into dynamic rollover if you aren't very careful. If you've shut down, get out and remove the snow from around the skids, to check to make sure the skids are clear. It's best if you can give yourself something to use as a reference. A stake, or clearing a spot right down to the ground. Be easy on the controls, and once clear of the surface, get out of the snowball quickly.

There is a good saying that may help. "If in doubt, don't".

[SPS]

knhxyy

There was a thread on skids frozen back in December, it might be worth a read.

In brief though, lower tail (as above) or even use a pole as a lever under the skids, anything to ensure that the skids are not stuck before a start.

Also beware that latent heat from the skids may melt ice/snow on landing, only to refreeze in minutes. Never trust that ice or snow even if you have landed for two minutes
and not shut down....

[Pac Rotors]

Doesnt Canadian Helicopters have a mountain flying flight school at Penticton. Just wondering if they teach flying in these types of conditions.

[hoverbover]

To all

Many thanks for the info, keep it coming, all the warnings are taken on board.And hopefully others will learn as much as possible, like me.

To TC

As you say the RFM allows flight in snow but their are no limits on temperatures etc.(except for the operation of the anti ice below +5 c with visible moisture, personnaly any time the temp is lower than +5 c I use the anti ice anyway visible moisture or not)
Many thanks for your sound advice, You learn something every day (I had always guessed that 0to+3 C would be the worse conditions for snow accreation and it would get less sticky the colder it got under 0C.)

To Hughes500

Thanks for the info, on the subject of aircraft could be !!!!!! But there is a 520 Notar in the UK (on the N reg at the moment)
and all advice is gratefully received

Thanks to EVERYONE and keep the info coming, and please don't worry I have no desire to fly in snow without the proper training(anybody got any ideas on who/where)but would like to be prepared.

Regards
hoverbover

[Hughes500]

Randy G, can't be anything to do with filter by pass its located by your right ear on HS,C and D models not sure on Notars. I like the C of G idea though or perhaps is there a danger of centre seat pax knocking off autorelight with a foot. The switch on all machines is about 2" off the floor ???

Nice topic this one espically as I had 2" of snow at the weekend on Dartmoor - ha ha I hear you say.
Cheers

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[ditchy]

Randy G has a point. When it happened to me the day I had multiple failures,I was only doing about 60 knots [vis about half a mile]so there wouldn't have been a big nose down attitude.That day was probably an ideal combination of temperature, moisture etc to get that heavy wet and sticky snow.We had resisted snow deflectors up until then as the TOT increase from them restricted our ability to move drills at the altitudes required. Used them after that if it even looked like snow.

My point was more that Flight Manuals these days are written by lawyers and they come up with all kinds of protective measures when a known weakness exists.When I can't think of an obvious reason for something that's what my suspicious mind concludes.

[Lu Zuckerman]

This was lifted from the FAA preliminary accident data report.

1996 BELL 406 HELICOPTER DROPPED OFF SKIERS, RETURNING TO
REPOSITION, SET HELICOPTER DOWN, SNOW CAVED, HELICOPTER ROLLED,
TAILBOOM OFF, ROTOR BLADE DAMAGED, JACKSON, WY


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The Cat

[Tiercel]

The no centre seat occupant restriction in falling snow on the Hughes 500 is because the original engine relight switch box was located lower on the console, and was difficult to reach with the centre seat occupied. All of our 500's (I'm talking in the 80's) had the relight moved to the upper right of the panel, and the centre seat restriction was lifted. It has nothing to do with C of G or the Filter Bypass door.

It is difficult to nail down blanket rules for flight in snow, as each helicopter and situation are unique. Not sure I can go along with the 'zero/zero' technique. This may work for very light snow conditions at airports but is not appropriate for use in heavier snow or unprepared sites, and can lead to more trouble than its worth.

One method commonly used for take-off in snow is to start to apply a little power until the snow begins to fly, retaining reference with the ground. Continue to apply power without going airborne until the snow has diminished to the point where a good reference is available. Lift the aircraft into a low hover, keeping your reference visual, then climb to a high hover and depart over the snowball. The main thing is to keep some reference available at all times.

For landing, plan your approach to a spot with some form of reference available. This can be the side of a building, a small tree, a fuel drum, etc. Bring the aircraft into a high hover, while maintaining reference with your spot, and allowing the downwash to clear the snow. Slowly lower the aircraft to the landing site as the clearing snow permits visual contact to be maintained.

Thomas Coupling...I have to take exception with several of your points. You say "Do not fly in visible moisture below +5 degrees, is good karma for MOST civvy helos. Due to the venturi effect at the engine intakes (Po) this drops to just above freezing and the engines could cut out!" This is absolute rubbish.

You also say "This time don't fly in snow below 0 degrees due to icing." Again, rubbish.

And...."If you've been on the frozen deck for too long, you may stick to it sufficiently to overtemp an engine trying to break free!!" Over temp in winter? What exactly do you fly?

Flight in snow, when properly equipped is as safe as flight in rain. There are places in the world after all where flight in heavy snow conditions are a daily occurance, and operations are conducted in a safe and efficient manner. Mr Coupling...If you don't know what you're talking about, please don't impart your dangerous level of inexperience on others.



[This message has been edited by Tiercel (edited 06 March 2001).]

[RW-1]

And of course in winter weather: DON't place your tongue on any part of the cold frozen heli, it might stick to it, and you will look silly. :)

(Well ... I had to add somethin ...)

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Marc

[This message has been edited by RW-1 (edited 06 March 2001).]

[hoverbover]

To Tiercel

All great advice, what about in flight conditions to avoid like certain temperatures etc.(i know its an open ended queston but any advice is greatly appreciated)

To Hughes500

Must have been pretty at the weekend, wasn't too far away myself but it was dark.

Again I hope others are learning as much from this thread as me,

Regards
hoverbover

[Seat Stick Interface]

My personal favourite for snow landings is to come to high hover, with escapes, and blow as much of the lose snow away.

zero speed landings are all very well, but as pointed out before you have no idea what is below the snow.

Unless there is a tactical reason for not blowing the snow I think that a high hover is a top plan. IMHO of course.

[CTD]

Greetings from the Great White North. Some good points brought up so far (and some REALLY bad ones), and if I may add a few, hopefully good ones, of my own......

When flying in snow.....
-Slow down.

-Beware of the fact that visual cues can be lost, even when visibility doesn't seem too bad, i.e. cloudy day when flying over lakes or vast expanses of unbroken snowcover. Approaches to snow covered areas in poor light conditions should always be made to a point or line of reference, which must be kept in sight at all times, as tiercel said in the landing / takeoff brief.

-When approaching a valley crossing or downslope in poor wx, slow down and plan your escape route/180º turn early to avoid shooting yourself into a whiteout condition. Also make sure your split-as$ed 180 doesn't take you over more unbroken white, this time at 60º of bank.

Most of this stuff is just plain common sense.

Accumulation is a different thing, and let's not confuse snow with ice. The RFM will provide restrictions regarding flight in moisture / snow and may offer relief when certain kits are installed (i.e. snow baffles / deflectors, relights, etc). Also, many operators in snowy climes develop and certify their own kits for their particular needs. When operating in these environments, it is imperative that the aircraft be properly equipped, as Randy G said.

Wet snow can accumulate on the fuselage, but in reality, the visibilities associated with heavy wet snow are usually so poor that prolonged flight is not an option anyway. If the vis is not reduced such as to slow you down, there likely won't be much in the way of accumulation. This build-up does not in any way affect the rotor or tail rotor, but may pose a problem for unprotected intakes, unheated pitot static systems etc.

Colder (< approx -5º) snow poses little threat in most PROPERLY EQUIPPED aircraft during reasonable flight conditions (vis > ½ mile), that meaning having the appropriate snow deflectors or what have you for that type. Again, there may be an RFM restriction or specified minimum vis.

Another thing to be careful of when working in a cold environment is the ability of blowing snow to infest every cavity in the aircraft. If the helicopter has been left outside for a prolonged period of SBS, you may find the tailboom, transmission deck, or engine bay full of hard packed snow. This can not only cause problems when it melts (and refreezes), but may also have C/G implications.

I add my hat to the ring of supporters of the high hover approach and slow, planned, visual departures. As the previous post said, avoid the 'zero-zero' thing unless you REALLY know what your doing, OR, if you're on fire, getting shot at or making movies....


[This message has been edited by CTD (edited 06 March 2001).]

[lmlanphere]

is there a common recommendation on how to remove frost or sticky snow from rotor blades? (other than waiting for it to melt)

[ditchy]

If sticky wet snow or precip has melted then refrozen on your blades you have a problem,but the normal hoar frost/light icing associated with overnight parking outside on both main and tail rotors will burn off rapidly at 100% Nr and some pitch is pulled.

I've had to do that on medium Bells where it takes 100% torque to hover with a less than maximum load initially but after a few seconds, performance improves remarkably as the ice burns off.Sounds crazy,I know, but as long as there is no imbalance all blades will clean very rapidly.

Picking up ice in flight is different, especially on the tail rotor which,from my experience, often sheds ice unevenly causing imbalance and serious vibration.Picking up ice in flight on the main blades can appear to have little effect, but the buildup is usually on the slower sections of the blade and affects the autorotative sections.To be avoided obviously,especially in single engined machines.

Aside from the ice building up on rotors,the sheer weight of ice on the fuselage can be surprisingly high.

[ditchy]

Tiercel,
I flew the 500D in the early 80's and had no restrictions on the centre seat because of the relight switch. Was this restriction in your Hughes Flight Manual or was it a directive from the Aviation Authority in your country?

[CTD]

I may be able to answer that (from a Canadian perspective at least, I'm not sure where Tiercel operated his).

I seem to remember it as a flight manual restriction, because I think I can still recall the temporary pages in the book. If memory serves, it resulted from an accident on the James Bay hydro development (around 1980?) where a 500 flamed out in falling snow and crashed. The investigation revealed the Auto Relight, which was located on the lower console between the passenger's feet was not turned on. The investigators also concluded that the Auto Relight could not be seen by the pilot if the center seat was occupied, and therefore the pilot could easily miss it if it were not on. The result was the restriction.

As a solution to the problem, most Canadian operators then relocated the Auto Relight to the outside of the instrument panel on the copilot's side, where the pilot could see it. If your 500 already had this or an equivalent mod applied, there would be no restriction. I think Tiecel may have his dates a little off, by the early eighties this would have already been done, I believe.

I haven't flown a 500 for 8 years, but that's how I remember it. Hope it sheds some light.

[Thomas coupling]

Tiercel: well where did you crawl from under?

You are quite correct in spotting my mistake regarding flight below +5 degrees in visible moisture,,,blah blah. It should have been 0 degrees. Sincere apologies to all for this.

Regarding the rest:

Last month a 6800hr russian ex mil EMS pilot killed himself doing a high hover approach to land. He cleared the lose snow from about 50' then descended and whilst doing so, shifted some more - lost vis references and struck the deck with a MRB. Good advice tiercel!

Engines overtemping whilst taking off: If the skids stick to the deck and you pull power to overcome the problem, depending on your a/c type and the amount of overcontrolling certain pilots may inflict on the controls one is in danger of overtorquing leading to an overtemp (it's happened, I've seen it) - dimbo...what other overtemp is there apart from me reading your drivel!

I learned my snow flying in Nova Scotia/Newfoundland and the Rockies military style...I suspect you've been reading about it or worse still teaching it without any quality experience....

I'm concerned that a newbie to the rotorhead forum feels that he has to respond with such venom. A shame really, I was beginning to appreciate this particular forum because of its more relaxed position on matters. Perhaps you've jumped across from another more agressive forum like: wannabees....! ;)

By all means question my contribution but blatant slagging only serves to dilute the purpose of this thread.

Go and have a drink on me.....with ice http://www.pprune.org/ubb/NonCGI/tongue.gif




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Thermal runaway.

[Randy_g]

Pac Rotors yes CHC does operate an advanced/mountain school in Penticton, B.C. Be a great place to go and learn some good techniques on flying in/around snow. Good skiing around there too. :)

There are arguments (for/against) for either technique high hover vs no hover. Some in heli-skiing use the no hover landing with great success. While myself and others have not had any problems with an approach to a hover to wait for the snow to clear.

I recommend cleaning all contaminants off of any critical surface before you start up. Unless you really know your a/c, you may not know when the contamination is gone. I won't gamble with peoples lives. It may be a pain in the butt to brush the snow/frost off the rotors, but it sure beats any of the alternatives. If you operate in an area where frost/snow is a problem, then use covers. They prevent rotors from developing frost, and snow won't freeze to the blades.

http://randyspics.tripod.ca/206winter2.jpg


You can see the blade covers on this 206, we also covered up the engine area and used an electric heater to keet the engine warm. Using the blade covers, I never had to clean frost off the blades.

Cheers

Randy_G

If you can't stand the heat ...

Then turn up the airconditioning !! :)

p.s. talk about irony, here I am downunda in the Land of Aus giving tips on flying in the snow. http://www.pprune.org/ubb/NonCGI/tongue.gif In case any of you don't think I know anything about winter flying, I have flown all over western Canada, and in the Cdn Arctic in the winter.

[helimutt]

pity the helo above didn't have itty bitty little covers on the tail rotor blades too.
All dressed up and no snow to blow!!!

[ShyTorque]

One further piece of advice. Despite all the problems your aircraft may have, the loss of visual cues close to the ground is what kills most people in these conditions, both during take-off and landing.

As well as external whiteout, beware of misting-up of the transparencies before and during take-off. Try to keep the doors open as long as possible while you are getting strapped in and started up, especially if you have been working hard to sweep off all that snow, free the skids etc. This will make sure any perspiration, heavy breathing etc (!) goes outside.

If you do get canopy misting make very sure you don't lift off until it is cleared; the last thing you want is your own self-induced IMC hover. Keep a soft cloth available to wipe the screen and use the screen demist if you have it.

In colder climates where the OAT gets lower than about minus five or so, canopy misting is likely to be less of a problem as the air is drier. Use of screen heat (or any inside heat) may not then be be a good idea as it may put snow contacting the airframe back into the sticky range causing build-up on the outside. Also, if you are carrying pax with snow on their clothing (skiers, soldiers, whatever) you don't want it to melt as it will make them wet which doesn't help them once they go back outside into the cold.

As always, get some instruction from someone who is used to the local conditions!

[Tiercel]

TC...I read my original post again, the one which seems to have offended you, then I read your reply and I stick by my original statement....."if you don't know what you're talking about......". I still don't get the overtemp though, seems to me the last thing you'd want to do if you were "stuck" in a helicopter would be to pull full power. Ever hear of dynamic rollover?

Randy G brings up a good point that some of the heli-ski pilots use the no-hover ldg technique, and I use it from time to time as well. To clarify my response to hoverbover's question for the benefit of Randy and others, these heliski guys are very high time mountain pilots, with heaps of experience flying in winter conditions. The person asking for advice in this forum has very little winter experience, and my response was tailored to that level.

BTW Thomas, to answer your off-handed comment about my lack of experience and having read about some of these things..... I'm a mid-time (just under 8K) ATPL who has spent most of his time in Western, Eastern and Arctic Canada, among other hot spots. And no, I do not currently share my lack of 'quality experience' with others on a professional basis.

[Grey Area]

Thomas stick to your guns, Tiercel, you are in error. I for one have flown in 1 type where engine anti-icing was required below +10 deg C and another that required engine anti-icing at +3 deg (in visibility <1000m due to moisture) both due to the temp drop in the engine intakes. Granted there are types which do not suffer as much, it is a product of the design of the air intake and such extras as FOD guards. (Remember P1 V1 T1 / P2 V2 T2 from your ATPL?)

Personally, I favour the zero/zero (no hover landing) technique and at least 1 reference. While I was doing supply trips in the antartic, if there was no suitable reference I used to use fire a flare (smoke if poss) into the snow, it gave me a reference and a good wind cue, very good if you are making an approach in a bowl where the surface wind could be 180 different from the 500' wind. (Why do chaps always want their stuff dropped halfway up a mountain in a bowl?)

BTW, 173mm icing in one sortie!!! look at http://www.gkn-whl.co.uk/eh101news/eh101news_current/hot.html

[hoverbover]

To all

2 Days 31 Posts and counting,excellent info from everyone,keep it coming.

To TC and Tiercel
Please don't start fighting, you both have more experience than I will ever have, don't fall out over this pleeeeease!

Thanks to one and all,keep the info coming !!!!

regards
hoverbover
PS
One thought I have had, are the blades warmer(friction) or colder (wind chill) than OAT,when flying ?

[Tiercel]

Grey Area! Whooaaa laddie! You are correct in what you say, but read again.....I didn't for one second say that ANTI ICE wasn't required below anything...what the man said was "Do not fly in visible moisture below 0 degrees, is good karma for MOST civvy pilots. Due to the venturi effect at the engine intakes (Po) this drops further causing freezing and the engines could cut out!" That is what I responded to, the "do not fly". Anti ice is different, true.

As I said in my last post, I use the no hover technique as well, but wouldn't recommend it until one becomes very comfortable with the other aspects of winter flying, which hoverbover by his own admission appears not to have achieved yet.

HoverB, Blades will be warmer due to friction.

[lmlanphere]

hover boy, wind chill only effects fleshy things like you and I.....

as far as the high hover versus zero zero, wouldn't it be better to lose visual reference (if inevitable) at ground level than in a high hover? how can you tell just how high that blowing snow will go?

[CTD]

Hover Bover...During flight operations the blades cannot physically get any colder than ambient, they will be slightly warmer due to friction. This will vary by type, tip speed and temperature.

‘Wind chill’ occurs when an object is cooled below ambient by the heat lost during the evaporation process, or ‘latent heat of vaporization’. So, unless the blades were sweating, they can’t be subject to wind chill! :) :)

Imlanphere: Not necessarily....to lose visual reference near ground level may not leave time to recover if you have a high closure rate, as you likely would in a no hover landing situation. Not good anywhere of course!

The high hover vs. no hover could be debated for ever. I use both up here in the Great White Wasteland, depending on the situation or loading. Both have their issues, and both must be used with caution and finess.

In the high hover method, the letdown must be smooth, slow and controlled, ALWAYS maintaining reference. This precludes its use when very heavy for some helicopters. The no hover method requires a precision approach, faith in what lies below, and a zero speed touchdown while staying ahead of your downwash. Not too bad in a 25 kt wind, but it can get very sporty on a calm day.
I personally believe it requires more skill and experience on the part of the pilot, and have to agree that it should be avoided, or at least practiced in a controlled environment, by folks who aren't winter current.

Thomas Coupling, I flew in all those places too. When were you in Newfoundland? Who were you with? From there?

[This message has been edited by CTD (edited 07 March 2001).]

[IHL]

To Hover Bover:

The only time snow is really a problem for take-off or landing is when it is newly fallen. After it has been on the ground for 3 or 4 days it usually doesn’t blow around much.
I prefer the techniques mentioned by Tiercel and CTD. When you arrive in a high hover ( 30 to 50 feet depending on snow and down-wash of aircraft) it takes a bit of patience to wait for the snow to clear , make sure you have good references when you're waiting. If its windy , with a lot of snow on the ground your reference for landing is sort of straight down out the side window; I would recommend practicing some landings using side window references for practice. You have to be sharp to do the no hover technique and it is certainly no something that I would use going into a night helipad.

There is one point that no one has mentioned and that is , after landing in deep snow you usually “pound it down ” i.e. pump the collective up and down until the skids reach the ground or the aircraft belly is resting on the snow. This prevents the gear from braking through the crust unexpectedly with the aircraft at ground idle. ( Canadian operators use bear paws on the back of the skids to keep the tail rotor clear .)

With regards to over-temping, I can’t comment on all aircraft but I know that if any aircraft that I’ve flown in the winter were to over-temp , I would bet that it couldn’t pass a power assurance check..

PS. Spend a winter season flying in Canada and all the snow mysteries will become clear.
IHL


[This message has been edited by IHL (edited 08 March 2001).]

[ditchy]

There will always be disagreement and discussion among pilots about approach and landing techniques for snow,as well as mountain technique.Having read with interest all in this post I thought I'd add a bit more for the benefit of those seeking information.The experienced people on this forum have their own ideas and are unlikely to modify them much now.There is one thing here that hasn't really been mentioned and thats to use a method with which you are comfortable.

When I first went Heliskiing I was forced to do approaches in a way that my instructor and boss swore was the "Correct way".It may have been to him,but I was more comfortable using a different[more flexible]technique that I developed over time and I believe I was safer doing what I was comfortable with than operating an obviously legitimate way but made me uneasy.In my opinion,listen to all the suggestions in here,but be comfortable with whatever you adopt.

I have been taught both flat and steep approach to landing technique and several methods of landing in snow.All of them have their good and bad points so I usually adapted a technique dependant on the conditions at the time,ie knowing how to use any technique and knowing which one would be safest.Most of the time I didn't have the luxury of being able to enter a high hover due to weight and altitude,so no hover was the only option.So,for those of you wanting info,learn all the techniques because you may not have the option of choosing the one you want.

Having re-read one of my posts I would like to clarify one thing.My remark about burning off hoar frost by hovering applies in conditions of no precipitation.ie the aircraft sitting outside on a cold clear night.It burns off frost evenly and quickly,I've never had an imbalance.If somehow there is contaminate on the blades that affects lift you'll notice it with a power check and there'll be loss of lift and vibration.This remark was made more in the context of discussion between experienced people and I was unwise to suggest it be adopted by newcomers to winter flying.An intimate familiarity with the aircraft is essential and would probably only be felt by someone operating an aircraft professionally on a daily basis.Having said that,to remove/melt frozen precip off rotors is time consuming and must be meticulously done to avoid imbalance between the blades or else you'll have serious vibrations that will not go away.

[Grey Area]

Tiercel, I've now reset the eyes/brain and foot/mouth circuit breakers. Apologies.

[CTD]

Addition to ShyTorque's good pointers on misting...... if it gets reeeeeeeeal cold, the problem becomes frosting. Even though the air is dry, the surface temperature of the windows can be -30 or -40º. The moisture from all those heavy breathing pax sticks hard, and at those temperatures, without windshield heat, can take forever to get rid of. As ShyQ says, leave the doors open (Brrrr), or start before loading pax and run the heater/defrost.

[Thomas coupling]

Hoverbover: apologies for getting overheated about snow!!

Tiercel: There are very few, if any 'current' civilian helos that are allowed to fly in icing, and the definition of icing is: flight in visible moisture below 0 degrees celcius (in the UK anyway). This includes snow. That's why I said "do not fly".

CTD: I was based at Shearwater on exchange to 423 sqdn for 3 years in early 80's. Did a couple of cross country's to nanaimo (if I remember the spelling) and stopped en route to do glacier and snow flying. Also flying off frigates from St Johns harbour because the ship was stuck solid in sea ice!!
Were you a mil pilot with the air force too?



------------------
Thermal runaway.

[CTD]

No, I was on the civvie side. Mainly Newfoundland in the 80's, Labrador and the Arctic in the 90's, with a couple of shots over in Asia and Africa to warm up in between :)

As for your 'no flight in visible moisture below 0ºC', good thing we don't have that regulation in Canada, there'd be no point to have helicopters! Excuse my ignorance, but is that applicable even if the aircraft is properly equipped with snow deflectors or the equivalent?

Randy, Tiercel, IHL, you're all from Canada, did you guys know that.....?

------------------
Crash Test Dummies are people, too.

[hoverbover]

To TC

No appologies needed, There is just SNOW way I want you two to fall out.

regards
hoverbover


[This message has been edited by hoverbover (edited 08 March 2001).]

[lmlanphere]

the regulations don't state what "icing" is, just that you're not supposed to knowingly fly into conditions conducive to it.... 'visible moisture below freezing' is what you learn in training, and I think it is accepted that snow is exempt.

[Ed Winchester]

Thomas Coupling,

As a mil pilot I was under the impression that rotor and airframe icing conditions are defined as cloud or fog within the temperature range 0 deg C to 30 deg C true, WHEN THE VISIBILITY IS LESS THAN 1000 METRES. Visibility reduction due to snow alone does not constitute an icing condition.

There are different rules for icing conditions (no go) and for flying in snow (dependent on viz/temperature)

http://www.stopstart.fsnet.co.uk/smilie/wokka.gif

[ShyTorque]

Wow, Ed! What sort of ice forms at 30 C? I take it you mean minus 30?

[Randy_g]

Yikes !! CTD I don't know the British regs, but if it could be interpreted that way... If we had a reg that could be interpreted that way, very few would be flying during the winter.

On that note, today is moving day and back to the Great White North. Talk to you guys :)

Cheers

Randy_g


Now where the heck did those heater controls go !!!! :)

[Thomas coupling]

Ed Winchester: that brings back memories, and yes that was the statement I was looking for (albeit -30 degrees!!). The mil fine tune it to some degree by putting a figure on it (1000m, probably because thats the dividing line between fog and mist?).

However I'm sure the mil also restrict snow to flying in those conditions 'below 500m' do they not?

You failed to mention also that precipitation is also included in the definition. In fact any precip in this range incurs some kind of airframe or engine icing actions. I would suggest that since rain/drizzle is precip, then so too is snow. Wet snow most certainly is.

CTD: My definition of visible moisture is rain / fog / cloud / snow / anything with water molecules in it. Provided you stay away from this then one can fly down to whatever the FLM tells you: -30 degrees for example. So flying around sub zero is a very common practice over here too!! but not in visible moisture, unless that particular model is specially fitted for sub zero flight envelopes (EC155, S76, puma, S61 for example).

[I know that below a very low temp (can't remember offhand I think it's -20 degrees?) one encounters supercooled droplets and yet lower than this: ice crystals, where a/c fly because they have negligible effect on the airframe, but that's not helo territory, I believe!]

Open to scrutiny??

------------------
Thermal runaway.

[This message has been edited by Thomas coupling (edited 09 March 2001).]

[Ed Winchester]

Shy Torque,

I'm gonna have to get up early to catch you out!

Tom C,

Close, but no cigar!

"You failed to mention also that precipitation is also included in the definition" (one too many also in there!)

That is because it isn't in the definition. The definition is verbatim.

So, flight in rotor and airframe icing conditions or hail or freezing rain/drizzle is prohibited.

As I said, VISIBILITY REDUCTION DUE TO SNOW ALONE DOES NOT CONSTITUTE AN ICING CONDITION. So we can fly in it.

"However, I'm sure the mil also restrict snow to flying in those conditions 'below 500m', do they not?"

Mate, I have not got a scooby what that question means!

If you mean do we have some restrictions to flying in snow, then yes. Obviously it will be different for each type.

For instance:

Flight in falling snow IS PERMITTED in OAT down to minus 30 deg C subject to the following:

(1)Flight is permitted in falling snow of any severity in OAT colder than minus 4 deg C. Flight must be in VMC and visual contact must be maintained with the ground.

(2)Flight in visibilities of less then 400m in OAT of minus 4 deg C or warmer must be avoided.

Finally, as you rightly suggested, WET SNOW is a hazard, and so, flying in recirculating snow at minus 4 deg C or warmer is kept to the mimimum.

Cheers,

Ed

PS. I'm off to Canada in the near future to fly for three years, so I look forward to flying in real snow, not the 1/2 inch covering which seems to grind this country to a halt!

http://www.stopstart.fsnet.co.uk/smilie/wokka.gif

[This message has been edited by Ed Winchester (edited 09 March 2001).]

[hoverbover]

To Everyone
Thanks for everyones input so far.
As I started this thread I was unsure of many things, and am learning all the time.

In flight below -10 C OAT airframe icing does not occur, is this correct or is at a fixed wing thing?

In the RFM the heli I fly is cleared for flight in blowing and falling snow,(providing the particle seperator is fitted)
but has no temp ranges.But is not cleared for flight in known icing.So is flying in snow below 0 C greater than3000m vis correct/incorrect.

I am a little confused at to what constitutes icing conditions.Does snow below zero C but greater than 1000m vis constitute icing conditions (just curious not thinking of flying in it)

regards
hoverbover

PS
Posted this just as ED Winchester posted his,hence I hadn't seen his post,very informative.Cheers

Ed Winchester
Have a good time, just dont fall asleep on the way home from the Pub in winter !!!!!


[This message has been edited by hoverbover (edited 09 March 2001).]

[ShyTorque]

Hoverbover,

Put simply, icing conditions are conditions where icing will build up somewhere on your aircraft. Depending on aircraft type it may be the engine intakes or elsewhere on the airframe that is most critical. It isn't possible to generalise too much because each type is different. Icing trials have to be carried out to determine limits / clearances for each type of aircraft.

Ice accretion rate depends on:

Temperature: Above OATs of zero C there is unlikely to be airframe ice, but engine intake pressure drop may cause local temperature drop to zero or below; hence a requirement for engine anti-ice on around 5 degrees C for turbine aircraft. Local heating (e.g. of the outer part of main rotor blades by air friction) may delay ice accretion on some parts of the airframe. Be aware that well below zero c precipitation can remain unfrozen till it hits your aircraft (down to minus 10 rings a bell but I might be wrong - if so someone please correct me.

Total water content: Simple, more water = more ice.

Droplet size: Affects the rate and type of accretion. Small droplets tend to freeze rapidly and form whitish (trapped air), low density, brittle ice. Large, supercooled drops are perhaps most dangerous as they freeze relatively slowly on airframe contact (contain more latent heat) and flow backwards in the airflow. This type of clear ice is "sticky" i.e. adheres more strongly to the surface and it is relatively dense and heavy. Rain ice is an extreme form.

Airspeed: Increasing airspeed cause more rapid droplet contact and increased accretion rate until about 400 kts when surface heating by air friction takes over and reduces it again.

Shape of the affected surface: Droplets have inertia and they cannot change direction as rapidly as the air supporting them. Thinner objects tend to collect more ice. Wider, more rounded ones collect less in the same conditions as the droplets can smoothly follow a gradual path change, although ice may form very rapidly at a stagnation point at the front of an object e.g. on the aircraft nose or ahead of a fairing, depending on design. The windscreen wiper arms are often a good indicator of what might be happening further back on the airframe. Some aircraft have an ice accretion probe (with a thin profile) fitted where the pilot can see it. Flight in icing conditions may then be allowed by the aircraft manufacturer until a certain ice build up occurs.

To my knowledge, the Super Puma is still the only helicopter cleared for unlimited ops in icing conditions. It has electrically heated blades, windscreens, intakes and other surfaces powered by an extra generator, covers over the control rods to main and tail rotors etc etc.

The best advice for helicopters and icing conditions is to vacate the conditions or adopt the "LOALI" principle.

"Land On And Leg It"!

[CTD]

Good explanation Shy. Your -10º analogy is generally correct, but the water has been known to stay in a supercooled state down to -25º.

The problem with icing is that it there we do not have a substantial body of knowledge on the subject. There are so many factors involved in its formation and accumulation, that accurately predicting its effect on a given flight regime is impossible. Something like predicting the weather....we know the general rules, but the complexity of the system defies our ability to accurately and precisely predict it.

As you said, stay out of it. Period.

[Ed Winchester]

Shy Torque and CTD,

Good stuff and wise words indeed - stay out of icing conditions!

[ShyTorque]

Just found a UK CAA AIC I had in mind. It is AIC 93/2000 (Pink 8) dated 19 Oct, entitled Frost, Ice & Snow on Aircraft.

This may be of some guidance.

ShyT

[Tiercel]

Good thread.

CTD, I got your e-mail but I deleted it before I got your address. http://www.pprune.org/ubb/NonCGI/frown.gif Send me another please.

[whatsarunway]

Excellent topic ,learning loads
i did a litle helisking in italy p2 and now i know why they did all that stuff , my italians not that great.
The one thing they used to do if at all posible was to do a really shallow approach and stay on the edge of translational lift , slowly moving foward to the landing site , this gave us a good idea how sticky the snow was , ie if it was going to cause a white out or if it had crusted in the top layer
also gave us an idea how deep the snow was and if the terrain was suitable.
ps , make sure they hold the skis horizontal , they dont mix well with Rotors

Ciao.

:)

[hoverbover]

A BIG THANK YOU to everyone who has posted ti this thread, I hope others have learned as much as me,and also how little I knew in the first place!

Again thanks to everyone for their time and effort

Regards and safe flying
hoverbover

[John Eacott]

Hopefully someone may have a solution, but we are often distracted in the snow by calls of "something's fallen off your 'elicopter". Needless to say, it's always a chunk of snow shedding from a bearpaw, after take off. At least, so far it is ;)

Any snow operators (Canadians or Kiwis, I'd guess) have this problem, or even better, a feasible fix? Bearpaws are Dart style thermoplastic jobs, only on the aft end of the skids.

TIA

[Joker's Wild]

Having operated for many years in the snow with bear paw equipped aircraft, I'm not sure how to answer. I can't recall having anyone ever call me up on the radio to say they had seen something come off my aircraft just after takeoff.

I'm a little curious, do you get this a lot or just once in a while? Most of the passengers I flew in those years tended to be seasoned helicopter users. I don't know if that made a difference.

Nothing leaps to mind as to a fix for this. I kind of suspect it's just something one has to live with if using bear paws. :)

[John Eacott]

I used to have calls frequently the first season (5 years ago), but now it's just occasional enough to be a nuisance. Last Monday was the local police out playing on their skidoos, convinced that something important had fallen off!

We're operating from resort to resort, thus sometimes overflying downhill runs or lift lines, so we have a huge number of interested onlookers. 40 flights a day means we're bound to get a call or three, plus patched in to the resort radios means we can't hide :D

[BigJim]

John,

haven't had any calls regarding bits falling off, but always see lots of snow coming off in the mirrors and flying along side other helo's.
But have had plently of experience with passengers stomping their feet on the floor trying to remove snow from their shoes, usally just after takeoff - puts the ****s up me everytime!!.

Any experince along these lines??


BigJim :eek: :eek:

[John Eacott]

Talking ballast/pax shouldn't be allowed ;) After the first season of shifting skiers, we had to insert sheets of heavy gauge alloy on the floor, to protect the (crushed) honeycomb where ski boots had done their thing. That was through a thick rubber floor covering! Sheets of stainless steel around the door pillars & cabin sides for more protection, and a vigilant ground crew to 'discourage' knocking snow off against the door sill as they get in.

The rubber floor mat stops any noise from boots being knocked on the floor, but they certainly enjoy the ride, and a good heater soon warms things up once we're airborne.

Only a couple of weeks left to the end of our ski season, and NSW has had about 5 bushfires already, so no doubt we'll swing into that fairly soon.

Look out for a super large flag tow over the VFL Grand Final in two weeks, >40,000 sq ft :eek:

[BigJim]

John,

limit your pax to snowboarders only with soft boots!! (and make sure the good looking ones are always in the front), sure to solve nasty plastic boot marks :). We use plywood floor liners which are good, but I'm sure a moulded polythene liner made by Tufdeck would look much nicer :D

BigJim

[ 13 September 2001: Message edited by: BigJim ]

[SASless]

I saw this press release in a trade paper....

PRESS RELEASE

Date 08 October 2002

NTSB urges FAA to require helicopter Instrument Rating in snowy climes

The U.S. National Transportation Safety Board (NTSB) today urged the Federal Aviation Administration (FAA) to require “all helicopter pilots who conduct commercial, passenger-carrying flights in areas where flat light or whiteout conditions routinely occur to possess a helicopter-specific instrument rating and to demonstrate their instrument competency during initial and recurrent . . . check flights.” NTSB Recommendation A-02-33. In addition, NTSB wants FAA to require operators in these areas “to include safe practices for operating in flat light or whiteout conditions in their approved training programs,” and mandate “installation of radar altimeters in all helicopters conducting commercial, passenger-carrying operations in areas where flat light or whiteout conditions routinely occur.” NTSB Recommendations A-02-34 and A-02-35. The full text of these NTSB recommendations is available via Internet at http://www.ntsb.gov/recs/letters/2002/A02_33_35.pdf.


How many commerical operators will actively support these reccomendations and promptly equip the aircraft with the instruments and train and test their pilots to this standard? Care to hazard a guess......mine is "Zero...zip...nada....nil...."



:rolleyes:

[MamboBaas]

SASless,
I guess you're right. For commercial operators the only 3 things which matter, in order of priority are, profit, profit, profit. Which is rather sad as I seem to remember from some previous posts of yours that you once worked in Nigeria for a large operator of whom you seemed to be rather fond;) I seem to remember that one of their pilots from there went to fly a Bell 206 for the British Antarctic Survey and crashed in the snow. Of course that was said to have been due to a faulty heater causing carbon monoxide poisoning, but.....
:confused:

[GLSNightPilot]

Looking at the past history of the FAA in responding to NTSB recommendations, I believe the chances of the FAA accepting these is very close to zero. As regards the motives of operators, I think you're a little broad there, MamboBaas. The motive is not just profit, but short-range profit. Few look at next year, much less next quarter. They take the money & run now, & next year will take care of itself, if they're still in business. :(

[Dick Mitten]

I believe that in Canada low vis ops are a required part of recurrent training. Admittedly, it's only a few questions on a written test, usually administered in the spring. Maybe an IFR requirement wouldn't be a bad thing...

In Helicopters Mag issue #2/2001 (Canadian publication: www.helicoptersmagazine.com) there's an excellent article on low vis training. It's a good read for this (or any) time of year.

Can we be trusted to know and respect legal vis limits, or do we need to have more legislation? Since the CPL is already a legal, skills-and-knowledge certification, adding IFR for snowy conditions isn't a conceptual quantum leap. But it still wouldn't mitigate the issue of customer pressure to complete the mission. None of my LZs have an instrument approach, so an IFR rating and radar alt would help me avoid CFIT, but won't help me reach my destination.

The real point of such legislation must be to ensure that we can turn around after inadvertent flight into IMC. Fair enough. Keeping the skills sharp during a season of (primarily) VMC is another question. As is getting every friggin helicopter in Canada outfitted with a radar alt! Bet there'll be some operator resistance the that one!!

[John Bicker]

The problem still remains that very few pilots know what whiteout is. No it is not as everyone suspects flight in falling or blowing snow. For those who have never experienced it imagine flying along in the dark and flying into an unlit object that you obviously couldn't see. The same can happen in whiteout - it is so white or bright that your eye cannot differentiate. The worst situation is a flat overcast making flat light conditions.

All the instruments in the world will not help and are not a solution - a DC 10 in Antarctica proved this once. In flight visibility was in excess of 150 miles. White cloud base, white snow, white mountain no shadows - whoop whoop WTF...........

The problem will remain that unless you are aware of the phenomena you will not recognise it - simple.

You would have to ask why no less than 3 AS350's ended up lying on their sides in one day in Alaska - all from the same company. Instruments and instrument ratings is far from the answer.

[SASless]

Bicker.....Hi Ya, Buddy! I suppose that was the way Ops wanted them parked. Famous quote I heard up there was " I don't give a damn what the weather is....tell the SOB to get that aircraft to Fairbanks or he can find another job!" ......and the fourteen year veteran Alaska pilot did just that....told them to stuff their job up their bunghole and got another job the same day. If you are referring to the "large" company with the 121 fixed wing side... they had the highest accident rate in Alaska (helicopter side) for several years running. You are talking about the same company that also did the same thing with two 212's or a 212 and 412 just outside Deadhorse/Pruhoe Bay one year too? Red/Black/White machines.

[PPRUNE FAN#1]

John Bicker wasn't referring to Era, he was talking about Temsco. September 10, 1999 was a day Temsco would rather forget.

One of their Astars with six people aboard crashed in low-viz/flat light conditions up on a glacier in Alaska. A search was initiated and subsequently another Astar with two persons aboard crashed. A third Astar found them, picked them up and continued to search for the first downed Astar, but alas, even it crashed! All were relatively gentle crashes that tore the ships up but didn't hurt anyone very seriously (with the exception of one person on the original ship).

The Base Manager was out searching in a fourth Astar. One can only imagine his anxiety upon hearing that a total of three of his ships were down (with one hapless crew being involved in two accidents in the same day!).

It is noted that only one of the three pilots had an Instrument Rating. The NTSB must be using this as a "cookie-cutter" cause, but their reasoning is specious because none of the three pilots reported any problems controlling their respective aircraft prior to smooshing into the snow. They all hit fairly level and under control, hence the "C" in CFIT. We can therefore conclude that the Instrument Rating by itself would not have prevented any of these accidents.

But a radar altimeter might have! The pilots reported that they thought they were higher than they actually were (kind of a "duh!" eh?). Had the information from a RadAlt been available, they might have known otherwise.

Having an Instrument Rating does you absolutely no good if:
1) you don't know where you are relative to higher terrain; and
2) you have no way of knowing how high you are with respect to the terrain immediately under you.

[Q max]

.... economics dictate:

Rad Alts are worth it - save you a fortune when you need them!

[John Bicker]

Guess it was Temsco. Was there in July of '99 with a Cayman Islands registered MD 600 - don't ask!

Was intrigued by the FAR's or recommendations, that your survival equipment should include a mosquito/bug hat and at least a shotgun.

Figured out after flying around for a bit that the gun was there so that if you crashed you could shoot yourself before a bear ate you.

Beautiful place and would definitely return!

[Randy_g]

Rad alt didn't help that DC-10 in Antarctica. Nor will it help if you are flying towards steeply rising terrain. It would also help if you are actually watching it too. How safe would you feel riding shotgun while some guy flies at 200'agl while he watches the rad alt in poor viz ?? I think I would be asking him to please turn around !! Besides, didn't one of you say that one of the pilots already had an instrument rating ?? Did him a lot of good. ;)

Dick our company ops-spec requires training once per year on low-viz ops. But it doesn't take long to do a couple of 360's in the a/c at 200' agl (or whatever height you feel comfortable at). Generally speaking when doing VFR recurrent training, we almost always have a little time to do company minimum airspeed, low-level flying. We pick a day with some wind, and in between autos, t/r failures, we go and do a couple of 360's at low level in the infield of the airfield. You have to do an hour's training anyways. Besides it's fun, and gets us ready for orbitting fires ad nauseum. :D

Cheers

[SASless]

Randy....would not practicing 180's be more beneficial.....really....doing a 360 to get out of trouble seems .....well....kind of ethnic somehow!

Plus.....I would like to know just how many hundreds if not thousands of hours I have at 200 feet in bad vis.....heck...I would like to know how many hours I have at 50 feet in bad vis......tree tops give a great altitude reference from below....and amazingly enough....most tree trunks point up....there by giving one an attitude reference. In our cowboy days it was not unheard of to ask the cabin attendent to slide the cabin door back and look down to warn us of the sea.

[John Bicker]

Don't get confused here. The trap in the DC10 and I think the Alaskan incidents was "sector whiteout". In the DC10 incident the flight visibility was in excess of 150 miles. The FMS was programmed so that they were'nt where they thought they were which is really incidental. The whole crew thought they were in the clear and could see the coastline and several other features clearly. They were well below the cloudbase. The white cloudbase, white mountain covered in white snow was undetectable to the capabilities of the human eye. During all the investigations the same course was flown in a US military 212 from Mc Murdo about a year (I think) later to the day. The same conditions existed and said mountain was not visible. The conditions of sector whiteout are never apparent and you have no reason to even think about using instruments unless you know the symptoms that cause it. The conditions were VMC and the aircraft were not in any sort of precipitation.

Unless you have experienced it yourself it is difficult to appreciate or describe to someone else how deceptive it is.

[Cyclic Hotline]

To fully understand the NTSB recommendations, it might be worth reading the relevant accident reports.

Temsco #1 (http://www.ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19659&ntsbno=ANC99FA139&akey=1)

Temsco #2 (http://www.ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19666&ntsbno=ANC99LA140&akey=1)

Temsco #3 (http://www.ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19667&ntsbno=ANC99LA141&akey=1)

Coastal (http://www.ntsb.gov/NTSB/brief2.asp?ev_id=20001212X19667&ntsbno=ANC99LA141&akey=1)

Temsco committed to the NTSB that they would;

According to the operator's director of operations, and the Juneau base manager, the following operational and training changes have been incorporated.

(1) Competency checks of company pilot's ability to navigation solely by reference of instruments. These checks will be incorporated into the annual 135.293/.299 pilot check rides.

(2) Installation of radar altimeters in helicopters providing tours over snow-covered glacial terrain. All new helicopters will have factory installed radar altimeters, and existing helicopters will be retrofitted within one year.

(3) Relocation of the factory installed ELT from the right baggage compartment to the passenger cabin area, and relocate the ELT antenna from the tail boom area to the nose of the helicopter. In addition, portable antennas will be provided in the event the airframe mounted antenna or antenna wiring is damaged.

(4) Incorporate "flat light" conditions training into the annual pilot training.

(5) Provide hand-held, FM radios for each helicopter, in the event that the helicopter's radios are rendered inoperative.



When you are carrying paying tourists in new aircraft the cost of a rad-alt is peanuts to the cost of the entire aircraft (especially if you install a $5,000 stereo system :eek: ).

Any other costs incurred in operating safely will be peanuts in relation to your insurance premium after a disaster of this nature.

Whether it becomes mandated will be interesting to see, and quite how you define "snowy-climes" might also pose a challenge, as seasonally that covers a lot of territory!

A couple of other lessons from this might include notifying the appropriate authorities that you have a (number of) machine(s) missing, rather than have the local media calling the FAA for information about 3 A-stars crashing on the glacier (say, what):eek:!!!!!

Some time later, a TV crew appeared to film a show about this incident. In the segment however, only two helicopters crashed on the ice because they did not think the TV viewing public would believe that 3 could crash successively!:rolleyes:

As regards flat-light conditions, anyone who has been ski-ing has probably run into this exact condition - totally featureless terrain and the inability to determine any physical definition. CFIT in these conditions is not limited to helicopters and mountains, but also fixed wing aircraft in relatively good visibility and flat ground but a featureless landscape, sky and horizon.

Intentional IFR flight in the area these accidents occurred in would be guarantee the demise of anyone unfortunate enough to try it. I've met a couple of fixed-wing guys who inadvertently tried it (exhibiting severe shock) and also pulled quite a few wrecks out where they weren't so lucky!

John, you will be pleased to hear that Alaska has removed the requirement to carry a gun at all times in the State, as it is impossible to take it through Canada! It is however a pretty good idea if you are going to do much travelling to buy one there - if you ever faced up to a bear in the woods, you would wish you had it. As regards mosquito nets and bug-dope - never, ever, consider going anywhere in the North without them in your survival gear, as they WILL kill you! ;)

[Decks]

While its not exactly the time of year for it I was just curious for input from some of the seasoned snow flyers about the profiles they use when operating in snow.
1. Runway takeoff... I would assume pulling in all the power from flat pitch and transitioning away as quickly as possible avoiding the hover.
2. Landing.... A shallow approach with touchdown, again avoiding the hover... what about on un prepared LZ s for example in the mountains...?

Any input would greatly appreciated especially from those who have flown in the snow on wheels.
Thanks ...Decks

[B Sousa]

The guys who have seemed to do well in training in these conditions are Canadian Helicopters. www.canadianhelicopters.com
Other than comments here, you may want to get an email through and see if one of their instructors can give you some tips.
As for me I uses my snow card. Its blue and I hold it up to the sky. If the colors don't match, its time for coffee.

[MD900 Explorer]

Hey guys,

Whats the deal with the snow drama in the U.K?

MAN has had disruptions, LGW was like an ants nest gone wrong?

Is it right and proper that a country that has snow EVERY year has major disruptions due to ignorance??

I know that most line pilots in the UK have no experience in flying in snow and shiiiiit.'.............( I am waiting for the come back)

Only look at what the Canadiens and the Norwegians put in, and they manage ok, cos they know it's coming.

Are the UK Aviation and Road people ###ing stupid. Or are resources stretched past their limit due to ignorance.??

MD :mad: :mad:

Planks have a whole sort of de icing procedure going on, i would like to hear about the varoius experiences of de-icing in pprune. Rotors going or not?)

[Steve76]

The hanger is the best solution for deicing. That and staying out of the fluffy stuff. :hmm:

Don't worry mate: the drivers in canada are just as bad. Which is strange because they grew up with it.

[John Eacott]

MD900,

Familiar refrain, I first heard it about 1953 when British Railways couldn't cope with snow on the tracks :rolleyes:

I suspect the NS lads may have something to say about ability to fly in snow, etc. Horrible memories of Brent Field shuttles in driving snow, relying on the 212 intakes not to clog up :hmm:

[Nigel Osborn]

Come on John, you're not old enough to remember what British Railways did in 1953!!!!!!!!!!!!!!
It was worse in 1947.:O

[Head Turner]

What does your Flight Manual say about flying in snow. If it says you should not, then don't. If it says you can, then be sure to understand the limitations that are prescribed. Whiteout is always likely on take-off and landing. Do you know and have been instructed on snow take-offs and landings.

Saw a swan who hadn't had mums instructions and supervision on landing on the white stuff come to grief in a spectacular landing as white out conditions existed and the poor swan thought that the surface was several feet lower than it actually was. There were feathers and snow all mixed up, and it took a while for the swan to rearrange it's feathers back into flying condition.

If your pitot hasn't heat then for sure you should stay in bed.

[delta3]

Meribel, Alpe d'Huez

Some pictures taken in the summer of 2003.
Tried to post that last May but did not really got the IT to work.
Finally got it figured out.

I hope that this still has some value in view of the delay.....

http://www.e-sign.be/Private/heli


Alpe d'Huez Approach
http://www.e-sign.be/Private/heli/slides/Huez%20Approche.JPG

Alpe d'Huez Final
http://www.e-sign.be/Private/heli/slides/Huez%20Final.JPG

Meribel Approach 1
http://www.e-sign.be/Private/heli/slides/Meribel%20approach%201.jpg


Meribel approach 3
http://www.e-sign.be/Private/heli/slides/Meribel%20approach%203.jpg


Delta3

[rotorspeed]

Ref switching to IFR, all "Nos"! Firstly you wouldn't go from VFR to IFR in snow due to icing, assuming helo is is not icing approved, which only some bigger types are. Nor would you switch at low level, unless you were intending to climb up to MSA in which case you'd need to know that icing wasn't a risk. Which it almost certainly would be. And finally you would go IFR at low speed - well not very low speed anyway - as there is always a minimum IMC speed - typically 55 kts.

Flying in snow can be ok though depending on acft (and snow) type, and severity. Not sure what Kent run but if AS355, off top of my head recall limit as unlimited time over 1500m vis, 10 mins from 800m to 1500m and no go under 800m. Of course not ideal and you'd still keep a careful watch on ice/snow build up. Where the engine air intake is positioned is important - eg 206's without snow baffles are bad news as snow can block up the forward facing intake quickly.

Prob not a drama. Don't forget snow looks a lot more when travelling at speed. Especially at night!

[TeeS]

Hi KMS

A couple of points here - Firstly, flight in dry falling or blowing snow is not, in itself, considered to be icing conditions. For this reason, subject to Flight Manual limitations, the helicopter may be able to fly in IMC in snow. However, if the climb to MSA involves a climb into cloud and the temperature is below zero, then the helicopter would have to have an Icing Clearance (usually larger machines only.)

The other thing to remember is that most of this snow is in the form of showers and is therefore easily identified and avoided if required.

Essentially, I can't see any problem with what you have reported.

Cheers

TeeS

[Curtis E Carr]

There is, of course, the rather important issue of landing and taking off. When hovering, recirculation of snow can be a problem to such an extent that the pilot experiences "whiteout" conditions and is unable to see anything outside the cockpit resulting in disorientation and an accident. Consequently, a takeoff should normally involve an immediate transition to forward flight. Equally, when landing, the pilot should aim for a "zero-zero" landing; that is to say, aim for an easily identifiable point on the ground and plan your approach so that you land on the ground (zero feet) with no forward speed (zero speed). That way, any recirculation should always be behind you. If you slow down too much so that recirculation catches up with you, go around and try again.

If you have never experienced this before, a flight with a suitably experienced instructor is probably a good idea.

[SASless]

Nay Laddy, hot rum toddies and an open fire with a ski bunny attached to yer arm....now that is the way to fly in snow!:E

[headsethair]

Not a problem.
http://www.flyingtv.co.uk./snow.jpg

[Flying Lawyer]

KMS

VFR nav can be a little more tricky because the terrain looks very different and familiar landmarks may disappear. Lifting/putting down in fresh snow will result in a disconcerting white-out if you haven't been warned and told how to avoid it (Curtis gives one method) but even nondescript countryside looks beautiful covered in blanket of freshly fallen snow.

If you get the opportunity, take it.
If you feel uneasy about it, fly with a more experienced pilot until you feel comfortable.
It's an experience not to be missed.

[AlanM]

He was with us at Thames radar this morning - he went fairly low in his chase for snow as he disappeared off the radar when around leeds Castle (I have heard of chasing twisters....! :))

They then took a leisurely trip through H4/H10 back to Booker - getting lucky with LHR on Easterlies as they didn't need to hold.

Sounds like a fun morning out! :)

[IHL]

Kissmysquirrel:

I have flown in wet snow, dry snow, light snow, heavy snow, fluffy snow, re-circulating snow, blowing snow, drifting snow, snow pellets, snow grains, snow showers, snow squalls- day time and night time, VFR and IFR.

Taking-off and landing in conditions conducive to re-circulating snow is quite simple here’s how to do it.

Takeoff: Apply enough power to get the aircraft light on the landing gear and wait. The aircraft will become enveloped in a huge snow blizzard, eventually all the snow that is loose enough to blow will be blown away and you visibility will increase. When you have sufficient references do a towering take-off (trade-off airspeed for altitude) up to 30-50 feet or as required to get above the snowball before transitioning to forward flight.

On Landing: Arrive in a high hover 50-75 feet above the landing site and wait, as in the take-off phase the landing site will initially become obscured but after a while 1-2 minutes the landing references under the aircraft will be visible and then you can continue your decent to a normal landing. This is the easiest and safest way to do it; the no-hover landing technique requires more skill and you have to be certain that the landing site is suitable for your aircraft-not the type of procedure that you want to do in a confined area that you’ve never been into before.

Keep in mind that when using the above techniques your references could be inside the rotor disc so before you try it practice landings and take-offs with your references in close. You also have to ensure that you have Hover Out of Ground Effect (HOGE) performance.

Basically you use the helicopters rotor system as a snow blower.

[XT244]

@IHL

Sorry, but this „Snow-Blower-Takeoff-Landing-Procedure“ you will use with B206, H300, R22, R44, B47 etc.? :confused:

[IHL]

Definitely with a Bell 206, It will work with any helicopter as long as you have hover out of ground effect performance.

[Lama Bear]

"Arrive in a high hover 50-75 feet above the landing site and wait, as in the take-off phase the landing site will initially become obscured but after a while 1-2 minutes the landing references under the aircraft will be visible and then you can continue your decent to a normal landing."

You really don't have much experience do you? This "technique" would get you run out of the heli*ski business in about two landings.

[Matthew Parsons]

Lama,

I've used IHL's technique and I've used other techniques in snow covered mountains. What IHL mentioned works extremely well in areas where you'd never take skiers.

I think we're seeing good reasons why flying in snow is best learned on a course rather than online. Like the rest of our job, there are many variations to what may at first seem simple.

[IHL]

Lama Bear :

Thanks for the attack and Happy New Year.

The original post had nothing to do with heli-skiing.
I stressed in my post that you need to have HOGE performance.
You don't have HOGE performance if your dropping off skiers at 10,ooo feet.

As for experience, I may not have as much experience as a lot of the other posters; I have 7,000. + on helicopters and in Canada we do get on average, 6 Months with snow.

Go and try your no-hover technique into a poorly lit heli-pad at night and let me know how it works out.

[Max Contingency]

I have always found that a co-pilots nav bag or rucksack, thrown out onto the snow surface during a low speed pass, makes an excellent hover reference for the final approach.

If the landing subsequently proves too difficult then hey.....it wasn't your bag anyway. ;)

[Vfrpilotpb]

LIke almost anything we do in Helis Care and Attention are what is needed to have a good flight in snow covered conditions.

Like many other PPL(H) pilots I have ony a little experience in t/o and landing in snow, nobody prebriefed me, it was purely an extention of experience and involved much care and safety, I have flown once in actual falling snow conditions, because a Wx front beat me to my LZ that wont happen again, it was not nice.

But what a difference to the landscape snow makes, as other have said it takes some time to reajust your recognition of familier sites, but photos come out just brill

when in snow go very slow, even putting your skids on the ground starts to make you think much harder.


Vfr
Peter R-B

[Simon853]

Snow-Blower-Takeoff-Landing-Procedure


I thought that's what 200 hour CPLs were hired for, sweeping the helipad?;)

Si

[BigMike]

Snow you say? yep, got a bit at the moment and it dosnt look like we will be going too far.

http://i8.photobucket.com/albums/a3/Micksphotos/snow.jpg


Both techniques discribed are correct. It depends on the situation. I prefer the "zero zero" method, and this is the only way to go when at any sort of altitude. Then when lifting off, as well as moving forward, also a more positive climb angle to ensure you are not flying into something! Distances can be quite deceptive when flying in these conditions, especially at higher altitudes where there are no objects to give you scale. One thing to be carefull of, is when you start pulling collective, make sure you are not stuck to the snow/ice. A bit of a wiggle with pedals and cyclic should help.

There are lots more traps so be very carefull.

Off course, SASless has described the best method of all...

Fly safe.

[SASless]

It is sure the most fun too!


Regards the flying bit....the key lies in two areas I think. One is the lack of adequate visual reference to include depth perception and not having enough support upon landing and sinking into the soft stuff.

If you fly in snow, at some point you will experience White Out...that can happen rapidly...without warning and can be quite fatal. Be it in the hover, on approach, takeoff or in cruise....visual reference is all important....and being prepared for the loss of it when it happens means being able to resort to my favorite method afterwards or not. Depth perception can be deceptive in Snow....running landings might be fun but the ground run is much shorter in soft snow than on hard packed stuff.

Parking places take on a new dimension....any slope to them at all? Be prepared to go sledding if so....usually at about 30% of the necessary Nr for flying usually as I recall! If you think the Jamaican Bob Sled team looked a hoot, try a downhill course in a half running helicopter!

Leave yer bird all alone over night....and come back in the morning to discover a window vent was left open a crack...and the blowing snow is now safely stored in the helicopter...slam to the roof...now that is the start of a good day!

Walk into the nice warm cabin....then after a few hours walk out to start up and leave....and discover the battery can almost turn the starter....that is fun too. Oil and fuel gets thicker with the cold and engines get really crook if you are warm and they are not.

Night flying and landing lights in snow can be a thrill too....seems odd the way the snow flakes seem to be moving in flight.

Logistics gets interesting in the snow too...ever tried to roll a drum of fuel in 3-4 feet of snow....or walk without snow shoes in that depth of snow. If your bird (both types) are wearing snow shoes...so should you probably.

There was an accident on a mountain near Seattle....aircraft did not have snow shoes (Bear Pads) on it....and when a skid broke through the crusty surface....on it's side it went. The pilot bore the blame...despite his management neglecting to ensure the aircraft was properly equipped.

If you are going snow flying....please do it first under Adult supervision. Seek out some old pot bellied, balding, bearded ancient geezer and quiz him for his survival tips on how to do it without recreating his mistakes of the past. His beer bill you pick up will be a lot cheaper than paying for the stuff you tear up in the process of getting to look like him one day.

One of the best laughs ever....in Alaska...-35F at Noon....been that way for weeks. A government inspector noted with disdain I did not have a water filter on my pump and suggested I had committed a heinous safety violation. The fact any water in the drums was froze solid in the bottom of the barrel seemed to escape him. Ever try to pump Jet Fuel by hand in those temps.....great sport!

Night flying over deep snow...with a clear sky and full Moon shining is probably the most memorable sights I have seen. It certainly cannot be called "Night Flying" in the true sense. Ice crystals twinkling from the Moon light, rivers, lakes, and ponds all shining...wonderful clear air...bright stars.....makes all the other flights pale in comparison.

[BigMike]

Couldnt put it any better... There you go folks, SASless is avaliable for winter flying endorsements... although the beer bill may exceed the cost of the aircraft hire... http://i8.photobucket.com/albums/a3/Micksphotos/happy045.gif

[SASless]

Rum drinks on sandy beaches in the Caribbean this time of year reduce the tariff for my services....put me up in a nice beach front hotel...and we can video conference by computer and save you a lot of money. Plus the beach bunnies costumes are more pleasing to look at as compared to clunky ski boots and parka's.:E

[Lama Bear]

SaSless said....

"If you are going snow flying....please do it first under Adult supervision. Seek out some old pot bellied, balding, bearded ancient geezer and quiz him for his survival tips on how to do it without recreating his mistakes of the past. His beer bill you pick up will be a lot cheaper than paying for the stuff you tear up in the process of getting to look like him one day."

When did we meet? You sure know what I look like.

After 17 seasons of heliski and 8 of winter seismic Mexico is so lovely this time of year. This forumn is a close to deep snow/winter ops as I want get.

[SASless]

LB,

You flying a nice newly redone Huey by chance...lifting powerline stuff?

If you look around....most of us old farts look like that....it is the brass ear trumpet we carry that really gives us away as being helicopter pilots.

Me dear old Mum thinks I play piano in a brothel.....if the truth gets out it will break the old dear's heart!

[Lama Bear]

No more wire pulling.... ever!

I'm on a state fire and rescue contract in a very nicely redone Huey with the big engine. Good work and good people. Come on down, we are looking.

[headsethair]

Some interesting replies. SASless : White Out...that can happen rapidly...without warning and can be quite fatal

Is that like being quite pregnant ? :O

[Thomas coupling]

Queen song: "What a beautiful day.........."

-28 and 50km viz @ 4000'.


http://onfinite.com/libraries/242277/6f9.jpg

Happy New Year to you all :ok:

[hotzenplotz]

This Video (http://www.joha.stonedblog.de/misc/chris_ausparken.mpg) is a huge download with 27 MB, but it's worth seeing.
I guess the the machine flipped back because of the soft ground, after unloading the rotor.

[Capn Notarious]

Thank you for submitting that video.

[R22DRIVER]

I liked seeing the 'Give it some oooommmppphhhh' idea to get it clear of the snow but what ever happend to one of the rules of slope landings 'Never Turn Your Tail Towards The Slope!'???

R22 :confused:

[spencer17]

Lucky guy having a fenestron instead of normal tail rotor.

@R22DRIVER That is exactly what he did or do you turn your tail towards the slope ??
Towards the slope means uphill !!

Happy landings
Spencer17

[Thomas coupling]

I was waiting for something to happen after such a long download:zzz:

[hotzenplotz]

Disappointed because this didn't resulted in an accident?

I think the interesting question is how the machine got into this situation.

Nice to see the pilot handeld that situation.

[Lima Oscar]

I think the interesting question is how the machine got into this situation.
Nice to see the pilot handeld that situation.

the center of gravity of the EC135 is really on the rear, so as you said in your first message, when unloading the rotor, on a soft snowy ground the EC' fell on his fenestron !

Fortunately the pilot handled very well this situation !

[R22DRIVER]

Spencer,

Yes i did mean ' Never turn your tail towards the Upslope' ! Sorry for any confusion!

:ok:

[puntosaurus]

That's a pretty ballsy move. I think I'd have uncovered the rear of the skids first, just to be on the safe side.

[PANews]

It seems to be quite a common problem with this operator. A few years ago there was a still image of a similar scenario with the Austrian EMS EC135 at even steeper angle tail first down the embankment of a road. Not sure how that was recovered.
At the time the image was strictly not for publication - too embarassing I guess - just one to secretly whistle over.
Now times have moved on and there is less twitchiness about any suggestion of c of g 'problems' associated with that giant bit of structure around the fenestron.
It does make you wonder if c o g issues are a hidden reason for both Agusta and Bell not taking up with the fan-in-tail after the trials they undertook. The public version is that they did not want to used the design because it was associated with EC ..... it never worried them that Sikorky used a conventional t/r.

[Thomas coupling]

There is most definitely NO C of G aft issue with the EC135. God knows we sometimes wish it was aft!!!!!

I agree with the aforementioned though. The Fan should have been cleared of all nearby snow before "unsticking".

Shame there was no crash though:ugh: [Just joking...].

[SawThe Light]

T.C. is quite correct in that the EC 135 doesn't have a C of G problem. It has a landing gear position problem.

PANews spoke of the shot of one ship that had landed across a levee or similar and it had pivoted about the rear of the skids and was stuck tail down nearly vertical down the embankment. Probably happened as the pilot stepped out. Great shot but what an embarrassment.

Pity EC can't move the rear cross-tube back another 6 inches or so though as it seems it is currently positioned directly on the C of G. Even picking the bird up with a Tug-a-lug generally requires placing some ballast on the front of the skids to prevent it from tipping backwards.

[tigerfish]

STL - Try a TLC Heli Lift. What an incredible piece of kit. It seems to lift anything. ( & I am not connected!). Seiously they are worth looking at if you have a lift & shift problem.

[Lima Oscar]

T.C. is quite correct in that the EC 135 doesn't have a C of G problem. It has a landing gear position problem.


i haven't said that the EC135 have a CG problem ;)

[SawThe Light]

Lima Oscar

I agree that you didn't say it had a problem, just that it "is really on the rear". I was simply agreeing with TC that it didn't. Other than the nasty trait of wanting to sit on its tail on the ground, it is a delightful little machine.

[Hilico]

Mass of tail boom = 60kg if I remember a comment by the Essex Air Ambulance correctly.

[FlyingHead]

Just a thought, if the pilot had test the density of the snow during landing, by "jerking" the collective up and down in a gentle manner, maybe he could avoid the situation.

Cheers
Dick

[Lima Oscar]

Lima Oscar
I agree that you didn't say it had a problem, just that it "is really on the rear". I was simply agreeing with TC that it didn't. Other than the nasty trait of wanting to sit on its tail on the ground, it is a delightful little machine.

Ok no problem ;)

[FloaterNorthWest]

I always wished EC had moved the skid 6 inches rearward, it would have stopped it appearing in the camera lens!

Artist formerly known as FNW.

[Seniorpilot]

Hi folks,:)
this is Gilbert, the Austrian EC135 pilot (shown in action on the video)!


......if the pilot had test the density of the snow during landing, by "jerking" the collective up and down in a gentle manner, maybe he could avoid the situation. ....



Of course, I did! I also told the HEMS-crew to get out and report, wether the snow-skids where fully on the ground and how the surface is. He reported: "both skids well on ground, surface is hard"!
I shut down and when the rotor stopped, I went out normally. Just when my feet touched the ground, I heard a "sort of scratching" noise and the EC sunk rearwards, until the Fenestron-housing stopped it!
Actually the surface was frozen hard, but there was sort of powder-snow down under. The snow-skids would sink, including a greater piece of the hard surface!
Never experienced this before - flying EC135 since 1997 in mountainous areas of Austria.:ooh:
I have checked the situation of the Fenstron eagerly and decided, NOT to dig it out because I was afraid, it could sink even deeper?
We also tried to pull the aircraft into it`s normal attitude - no way!

The "recovery" maneuver was not a real problem - despite I should have made it a bit less harsh!? No limit on mast-moment, no uncommon feeling - she moved a bit too fast but, well, that was it! (No such training ever before!)

Losses: the tail-bumper was slightly damaged, replaced and a special-check was carried out. No further damages.
Reliable aircraft? I guess....

Kind regards,

old Gil. :D

[Lima Oscar]

Welcome Gilbert !

Thanks for the explications and well done ;)

Regards

LO

[FlyingHead]

Hi Gilbert, sorry I didn't want to offence you. But you are right I saw similar thing happen in Canada. An Astar land by a lake, where the snow seem to be ok but when the rotor stop and the pilot disembark, the A/C sunk in the snow. I was flying by and the pilot call me to look during he attemp a take off, same as yours. Basically good job.
Cheers
Dick

[Phoinix]

Hello Gilbert

Thanks for those explanations. One thing still bothers me. Why didn't you dig away the snow from the top of the skids? Wasn't that the main obstacle sticking you to the ground?

[Seniorpilot]

Hi Phoinix:)

yeah, was thinking about this (even the snow on top of the skid was not the real reason for "sinking")
Finally, I decided, not to remove snow or dig somehow for not to destabilise the tricky ground!
Seen retrospectively, I would move more slowly (but I had to consider the mast-moment limit, of course) !:hmm:

Lesson learned: TAKE ADDITIONAL CARE - NEVER TRUST THE SNOW TOO MUCH!

Kindest regards,

old Gil.:)

[Phoinix]

We all make mistakes and we all learn; from our own experiences and from others. Thank you for sharing that one with us :)

In the end, everything turned out OK, that's important :ok:

Regards

[Gerhardt]

Like the others said, thanks for the narrative, and we're all glad everything worked out well!

[Phoinix]

Hey Gilbert!

Someone over here wishes to know, if you are still wearing those big moustache :}

[Seniorpilot]

Hi Phoinix:)

yes,yes - part of me! (Helps to balance....!)

Kind regards,

Gilbert, the senior

[warrigal]

Good onya Gil! Tricky terrain, tricky surface and tricky recovery.Well done!

[Seniorpilot]

Hi Warrigal:)

Yeah - my wording! Thank you!
Another lesson learned, yes!
This time, tricky terrain and conditions every day!
Foggy weather, fresh snow, poor visibility - many missions!
Last weekend, we had stormy northwind - up to 80 kts max. in 12000ft!
Hard winter this year!
You`re better off in Australia, rather than in Austria, at the time beeing?
I dream so....

Kind regards,

old Gil:) :)

[Scotto]

Hello,
Anyone have any rules of thumb about flying in snow. More like when icing may occur, ie...temps, relative humidity freezing level? I fly vfr and am familiar with when icing may occur when in the clouds, but there isn't much info I can find on icing when it comes to flying while it's snowing.

Thanks for your help

S

[malabo]

Never picked up any ice in snow. Let me define icing in a helicopter as picking up enough ice on the blades to register an increase in torque. Snow will build up everywhere else that it can, like the wiper blades, windshield, crosstubes, etc, but won't affect the operation of the helicopter. There are some restrictions on snow operations that require baffles or other deflectors to keep the snow away from the engine intakes but that is not an "icing" problem.

Rule of thumb is if you can see the next tree or the next powerpole you keep going, otherwise you sit and wait in a hover at said tree until you can see the next one. Heavy snowfall tends to come in showers, so if you can wait out the worst for 20-30 minutes you can carry on. If I had a concern about snow it is the variable visibility - a few feet one minute, 10 miles the next.

malabo

[paco]

"Rule of thumb is if you can see the next tree or the next powerpole you keep going, otherwise you sit and wait in a hover"



Increase that to about 6 poles you might be nearer the mark. And I would be on the ground, not hovering.

Scotto, if you're not in precipitation, you won't get icing, and the time to start looking out is when you have to turn the anti-icing on, which is 4 degrees or so in the 206. I seem to remember something about the 206 (in UK anyway) not being able to fly in snow anyway, but I may be wrong.

As malabo says, you may need baffles or deflectors, or even snow kits to protect the engine, depending on the machine, but dry powdery snow is otherwise not a problem for the airframe, until it starts to restrict your vis.

Wet, clingy snow won't get off the windcscreen and won't blow off in flight (downwash in the hover is best) so don't even try. Get yer backside on the ground with a coffee in your hand at the nearest hostelry first!

Phil

[remote hook]

Scotto,
Anytime you're flying in wet snow around freezing, as Paco says, you either want to be keeping a close eye on things, or having said coffee. That said, we do a LOT of work in these conditions on the West Coast, you just have to monitor them closely, and bear in mind an Astar will be different to a 500 or 206 etc etc. Know your flight manual and you'll be fine a far as an type specific issues/limitations.

Flying in colder, falling snow, is actually preferable to rain for me in many instances. A) It doesn't stick to the window or distort your vision as rain does, and B) you usually don't have fogging issues on the inside of the wind screen. However, and this is a really big however, in very low vis operations as Malabo is talking about, you have to be very careful about flying over open, or completely snow covered areas. This can lead to "whiteout" situations, that in a VFR ship, can and will lead to a nasty accident.

There are a few "rules of thumb" I use, but mainly when operating below the treeline, don't attempt to transit an area you cannot see across such as a frozen lake, or even open fields when the vis is right down in the one power pole example. This is a sure way to get disoriented, and leads to a number of accidents every year. Fly the edge of lakes or fields along the tree-line.

The other thing, is to be very aware of the "snowball" on approach and departure in fresh snow. This is the cause of a number of rollovers every season, and there are a few things you can do to mitigate the effects of blowing on liftoff or dept. First, ALWAYS land next to something dark in colour, a rock or bush will work, and be close, even if you land ON the bush. This is often your only point of reference. Same goes for dept, choose a dark ref point close to the machine, and maintian contact with it until you are either able to rise above the snowball, or transition forward from it. Your choice of dept will be governed by an number of things that I really can't type out at this speed....lol

I wouldn't worry about above the tree-line work right now, that's a bit further down the road for you judging by your question, But, if you do find youreself going there, make sure you've got very good weather until you get some training and more experience in those areas.

Good luck, and remember this is by no means a complete lesson on snow flying, get some training with an experienced pilot if at all possible.

RH

[170']

Scotto...

There's some useful info here?

http://www.caa.govt.nz/fulltext/Safety_booklets/Aircraft_Icing_Handbook.pdf

Be careful out there ;) ...170'

[Head Turner]

Use the Landing light to give you a clue to where the snow surface is, when landing

[perfrej]

"Rule of thumb is if you can see the next tree or the next powerpole you keep going, otherwise you sit and wait in a hover"



Increase that to about 6 poles you might be nearer the mark. And I would be on the ground, not hovering.

Scotto, if you're not in precipitation, you won't get icing, and the time to start looking out is when you have to turn the anti-icing on, which is 4 degrees or so in the 206. I seem to remember something about the 206 (in UK anyway) not being able to fly in snow anyway, but I may be wrong.

As malabo says, you may need baffles or deflectors, or even snow kits to protect the engine, depending on the machine, but dry powdery snow is otherwise not a problem for the airframe, until it starts to restrict your vis.

Wet, clingy snow won't get off the windcscreen and won't blow off in flight (downwash in the hover is best) so don't even try. Get yer backside on the ground with a coffee in your hand at the nearest hostelry first!

Phil

206 in snow is allowed with particle separator and snow deflector plates. Otherwise I beleive that "flight in visible percipitation below 4 deg C" is not allowed.

/perfrej

[ThomasTheTankEngine]

I have not done a lot of flying in snow but one thing I have noticed is that thicker snow started to stick and remain on the screen at about +2°C where as rain or thin powdery snow needs a temperature of 0°C or less to stick.

Before I saw this I always thought you would have to have a tempreture of 0°C or less for snow to stick.

[malabo]

You can fly below 4.4C (40 deg F) without the deflectors and separators (but not falling or blowing snow) but the engine anti-ice has to be on in visible moisture. Has to be off if OAT is over 4.4C. Take your pick of 4 or 5 if you've got a fancy digital thermometer in C.

For flight in falling or blowing snow you need FMS10 and 12 (particle separator and snow deflectors) installed, and then there are some limits on how long you can hover, idle, etc.

Good idea to have the Engine Automatic Re-Ignition (FMS18) installed too. It will also make a "tvarich" or true believer out of you when you're hovering over somewhere inhospitable on a dark dreary day and the little orange light tells you that it's done you a favor and relit the engine.

malabo

[paco]

My comment about hovering was to avoid the whiteout situation.

Thanks for the tips about the 206.

Phil

[Scotto]

Thanks for your input. The BH407 I fly has the intake baffles that will be installed soon. I have flown UH-1's in Germany for three years, but I didn't fly that much in actual snowing conditions. Done plenty of whiteout training and so on. I was just wonding if snow sticking on the acft during flight would accumulate into ice. Any experience with snow melting on the acft (after you push it out of the hanger) and refreezing on it in flight.

Thanks for you input again.

S

[Flying Bull]

Thats the time, when to start thinking about alternate means of transport ;-)
10 nm further east was sunshine - thats what my boss said...

http://www.uheeren.de/images/Schalke0.jpg

[MightyGem]

Any experience with snow melting on the acft (after you push it out of the hanger) and refreezing on it in flight.

No, but having landed in dry powder snow there was a liberal amount over the windscreen. Came back 30 mins later to find that it had melted due to the warmth of the screen, then quickly refrozen due to the sub zero temperatures. Allways cleared the screen after landing from then on.

[Spunk]

Hi FlyingBull,

did you land in- or outside the arena???:eek:

[ampan]

As a result of an accident that occurred down this end of the planet over 30 years ago, a theory was developed that in whiteout conditions, the human brain will generate a false horizon when faced with a wall of white with dark objects either side.

Does this actually occur? The video below is of a standard whiteout situation in Antartica. The camera does not capture any dark objects to the left or right, but I can't see how that could make any difference re the pilot's perception of the horizon. If it isn't there, it isn't there, one would think.

KwqIayoYdII

[[email protected]]

Errr - he's flying on instruments! He has an AI to tell him where the horizon is.

[ampan]

Exactly. He's on instruments, until he's almost on the runway. The pilot on the accident flight was VMC, and faced that wall of white for a whole two minutes before deciding to climb out. The excuse put forward for his not doing so immediately is the false horizon theory.

[[email protected]]

Ah I see where you are coming from now ampan.

However reviewing a video won't help you understand because you have none of the physiological factors present.

The propreoceptive feedback (seat of the pants feelings) from muscles and nerves allied with the semi-circular canals in the ears provide powerful orientation signals - the brain will interpret these (possibly erroneously) and calculate what it thinks is the local vertical and therefore where the horizon is.

[212man]

In the accident you refer to the illusion was optical, not created within the brain. See here for some more http://www.erebus.co.nz/Portals/4/Documents/Reports/Mahon/Whiteout%20Phenomenon.pdf

[[email protected]]

No, the visual perception and interpretation of what is actually there is the problem and that lies fairly and squarely within the brain. By definition any optical illusion is the brain incorrectly interpreting the visual cues.

This type of whiteout, where texture cannot be defined, is observable when skiing in flat light - you don't see the bumps until you ski into them.

'Hidden' rideglines are also a problem on NVG (it is lack of depth perception and texture information again) - I encountered it last year in the Falklands (very dark) and was saved by the rad-alt.

[micraman]

During my time as a Army Pilot as soon as the snow arrived we were rebriefed about snow landings and take-offs etc,also we had to fly with a QHI and demonsrate we could carry out this type of flying,what happens as a civilian or do you learn the hard way.

[SASless]

During my time as a Army Pilot as soon as the snow arrived we were rebriefed about snow landings and take-offs etc,also we had to fly with a QHI and demonsrate we could carry out this type of flying....

Do you think the Civilian world of flying comes to a halt because of a bit of Snow?

Do you reckon it is economical to run to a Check Pilot for training anytime something new shows up in the form of weather or task?

You reckon a "Professional" pilot should be able to cope with such encounters...through training, experience, and education or have the commonsense to wait it out until conditions improve?

[ShyTorque]

what happens as a civilian or do you learn the hard way.

Bearing in mind the inexperience of many of today's "hour-building" instructors, I would suggest that this isn't included in most helicopter pilots' training.

As a military pilot, working in a more supervised and mandatory ongoing training environment, you were privy to a far more comprehensive (and ongoing) syllabus. ;)

[hihover]

Thats a very reasonable question. Unfortunately it is sometimes difficult to get a reasonable answer.

There are no hard and fast rules and it depends very much on where you are, what you are required to do, and who pays the bills.

If I am going to send someone out in my helicopter, in the snow, then I will make sure he is capable. If he is not, or if there is doubt, I have two options:

1. Wait for the snow to clear.
2. Give him some training.

Either way it is going to cost money.

I can't think of any responsible operator who will allow their pilots to experiment in the snow without guidance.

I'd take the British Army method every time, unfortunately, as a civvy I now have to have a slightly different outlook.

Tam Macklin

[SASless]

I reckon it depends where one builds one's hours.

[fijdor]

Here you can see what a nice overcast winter day looks like on the St Lawrence river in Canada . Photo taken from the ground during the seal hunt season.

NO PHOTOSHOPPED. People you see are news reporters.

No blowing snow of course but it gives you a idea of what a "whiteout condition" looks like, that's one of them.

NOT a good time to head back to shore, 40 miles out

JD


http://i683.photobucket.com/albums/vv196/jacdor/800px-White-out_hg.jpg

[Gordy]

Snow training is part of the initial part 135 training where I work. We do about 2 hours of ground followed by a flight up into deep snow country to practice the techniques. We also conduct quarterly training, (albeit only 30 to 60 minutes of flight--unless more is needed). We try to make at least one of the quarterly's to be in deep snow.

Here is a brief list of topics we cover...this is off the top of my head as I do not have my training manuals at hand---hope it helps:

Discussion Topics:
1. Weather and wind.
2. High and low reconnaissance, including: ridges, valleys, snow conditions, wind evaluation, slope evaluation and approach/departure corridors..
3. Approach and Landing, including: angle, obstacle avoidance, white out, powder vs. packed ice, flat light, slopes, sliding, settling onto snow, packing down, shutting down.
4. Lift off and departure, including: clearing the skis, start up on ice, white out, TR clearance, departure path choices.

[ShyTorque]

NO PHOTOSHOPPED. People you see are news reporters.

OK, But why are they walking along a cloud? ;)

Gordy, sounds good to me.

We used to do an annual ski expeditition to southern Germany, oops no sorry, I mean a "mountain/snow flying training expedition". Served me very well; I wouldn't consider myself an expert by any means but the basics taught there have kept me out of trouble.

At least as far as flying goes....

[Decredenza]

Thought you might be interested in the Helicopter Association of Canada's heliskiing guidelines

http://www.h-a-c.ca/heliskiing.pdf

and a friend at work...

Snow Landing video by snippet58 - Photobucket (http://s385.photobucket.com/albums/oo293/snippet58/?action=view&current=BlueTongue.mp4)

[Bellrider]

Wow! That´s really a lot of powder in the 2.video! Good job!
I had some problems after a landing , the Bell06 was safe on ground for about 20 seconds, but suddenly the skids broke in, that means i looked in the sky and tailrotor was only some inches befor touching the frozen snow! really shocking! My advice: always use snow skids and check with pitch mouvements the condition off the terrain below!



(sorry for bad english, i´am from bavaria:confused::mad:)

[Bellrider]

The same happened to a rescue heli:

Christophorus 7 helps itself - YouTube

[SASless]

My advice: always use snowboards on the skids

Ever wonder why they are called "Snow Boards"?:D

Very sound advice....especially if flying a MD-500.

The other laugh is to land as described...determine it safe to shutdown...then step out of the aircraft and sink up to your waist in the Snow. Sometimes Snow Shoes should go along if your birdie is wearing Snow Boards (Bear Claws).