We should not point fingers
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SASless wrote,
Oleary,
Where are you getting your information about the improper overhaul at Columbia?
That's been around for some time.
While you at CHC were flying that bird at "Topping" all those forty thousand hours....were you still using standard Sikorsky TBO data based upon their initial flight testing for certification or did CHC modify that data to reflect all those hi-power settings and cycles and wear and tear from unusual forces caused by Logging and Water hauling? The aircraft TBO's on drivetrain and dynamic fatigue loaded parts are impacted by the power vs time at power spectrum as I am sure you are aware.
I never flew for CHC, I flew for Okanagan.
I never logged and did very little water bucketing.
At Okanagan when the engines were set at 140-2 Ng limits (and that was NOT for logging, it was at Edson) life was reduced accordingly.
Carson by the use of Plus Spec Power settings and higher weights and the use of 2.5 minute OEI power for takeoffs really loaded up the aircraft in that regard and some thought might be given to what effect that has on TBO's.
Don't know what Carson did, so I can't comment.
As you seem to say you at CHC operated the aircraft and had Topping issues....what techniques did you use to avoid "Topping Out"? Did you limit weights, abort takeoffs that caused you to go beyond the limits for Ng...or did you do as most Loggers do....carry all the weight you could even if it meant drooping some Nr so long as you could clear the barriers?
I said NOTHING about how CHC operates their aircraft - I NEVER FLEW FOR THEM.
.... and again, I NEVER LOGGED!
I posted the NTSB Report earlier if you want to review that and point out any errors you may think they made for us.
The veracity of that NTSB report has been contested before, and will be again, I expect.
Finally, to my original point, I don't need a number on a piece of paper to tell me whether or not I have enough power to take off from a confined area, ...
... not with a 204 (-11), 205 (-13), 212 (-3), 58T (-3) ----- or a 61.
Oleary,
Where are you getting your information about the improper overhaul at Columbia?
That's been around for some time.
While you at CHC were flying that bird at "Topping" all those forty thousand hours....were you still using standard Sikorsky TBO data based upon their initial flight testing for certification or did CHC modify that data to reflect all those hi-power settings and cycles and wear and tear from unusual forces caused by Logging and Water hauling? The aircraft TBO's on drivetrain and dynamic fatigue loaded parts are impacted by the power vs time at power spectrum as I am sure you are aware.
I never flew for CHC, I flew for Okanagan.
I never logged and did very little water bucketing.
At Okanagan when the engines were set at 140-2 Ng limits (and that was NOT for logging, it was at Edson) life was reduced accordingly.
Carson by the use of Plus Spec Power settings and higher weights and the use of 2.5 minute OEI power for takeoffs really loaded up the aircraft in that regard and some thought might be given to what effect that has on TBO's.
Don't know what Carson did, so I can't comment.
As you seem to say you at CHC operated the aircraft and had Topping issues....what techniques did you use to avoid "Topping Out"? Did you limit weights, abort takeoffs that caused you to go beyond the limits for Ng...or did you do as most Loggers do....carry all the weight you could even if it meant drooping some Nr so long as you could clear the barriers?
I said NOTHING about how CHC operates their aircraft - I NEVER FLEW FOR THEM.
.... and again, I NEVER LOGGED!
I posted the NTSB Report earlier if you want to review that and point out any errors you may think they made for us.
The veracity of that NTSB report has been contested before, and will be again, I expect.
Finally, to my original point, I don't need a number on a piece of paper to tell me whether or not I have enough power to take off from a confined area, ...
... not with a 204 (-11), 205 (-13), 212 (-3), 58T (-3) ----- or a 61.
Last edited by oleary; 9th Feb 2013 at 22:55.
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Nothing is ever mentioned about the machine being operated within the HV curve, which for a Part 29 helicopter with more than 9 passengers, is a limitation.
A limitation - something that is not permitted.
The rate of rotor RPM droop is also pretty consistent throughout, and also consistent with the rotor RPM droop in the previous takeoffs...
A limitation - something that is not permitted.
The rate of rotor RPM droop is also pretty consistent throughout, and also consistent with the rotor RPM droop in the previous takeoffs...
Oleary,
I thought Okanagan grew into CHC...or am I mistaken in thinking that.
You remind us the concern about the questionable overhaul has been around for sometime. Fine....but as I asked...what is the source for that conjecture....Happy Hour at a Tavern somewhere or some credible source.
So you never Logged....and did very little Water Bucket work....so may we assume you have a passenger hauling background with the 61 then....and it was done in very tightly controlled environments?
How did Okanagan calculate the TBO reductions when operating at the higher Ng....did they construct a Power Spectrum and conduct flight testing and other techniques to arrive a the revised TBO's? Or, did they over time recap component changes due to unscheduled replacement of parts and arrive at the TBO that way?
Tell us how Okanagan Procedures for 140-2 limits altered the performance charts so Pilots could calculate their Take Off performance and then adjust the aircraft's payload to account for the conditions extant at the time the flights were being made.
If you are aware of criticisms of this NTSB Report...tell us about them if you would.
Shawn,
Does the HV rules for a Part 29 aircraft apply to one being operated as a Public Use Aircraft as when this 61 was contracted to the US Forest Service? I think the NTSB discussed all that and pointed out some problems in the way the FAA/USFS systems were lacking.
I also thought about how the aircraft would perform OEI at the weights, heights, and Temps they normally do in Fire Operations. That would have been an interesting discussion by itself.
The 61 got the heave ho from the North Sea because it was considered under powered....particularly compared to the aircraft that replaced it at the big North Sea Operators and that was at Sea Level and much cooler temperatures.
I thought Okanagan grew into CHC...or am I mistaken in thinking that.
You remind us the concern about the questionable overhaul has been around for sometime. Fine....but as I asked...what is the source for that conjecture....Happy Hour at a Tavern somewhere or some credible source.
So you never Logged....and did very little Water Bucket work....so may we assume you have a passenger hauling background with the 61 then....and it was done in very tightly controlled environments?
How did Okanagan calculate the TBO reductions when operating at the higher Ng....did they construct a Power Spectrum and conduct flight testing and other techniques to arrive a the revised TBO's? Or, did they over time recap component changes due to unscheduled replacement of parts and arrive at the TBO that way?
Tell us how Okanagan Procedures for 140-2 limits altered the performance charts so Pilots could calculate their Take Off performance and then adjust the aircraft's payload to account for the conditions extant at the time the flights were being made.
If you are aware of criticisms of this NTSB Report...tell us about them if you would.
Shawn,
Does the HV rules for a Part 29 aircraft apply to one being operated as a Public Use Aircraft as when this 61 was contracted to the US Forest Service? I think the NTSB discussed all that and pointed out some problems in the way the FAA/USFS systems were lacking.
I also thought about how the aircraft would perform OEI at the weights, heights, and Temps they normally do in Fire Operations. That would have been an interesting discussion by itself.
The 61 got the heave ho from the North Sea because it was considered under powered....particularly compared to the aircraft that replaced it at the big North Sea Operators and that was at Sea Level and much cooler temperatures.
HV Charts are provided as advisory informaton
Height Velocity information is provided in either the emergency procedures or emergency performance charts sections of the flight manual not the limitations section. As such, it is provided as advisory information. I believe that HV information is not provided as rules for operation of the helicopter but rather as an advisory for those areas of the flight envelop to be avoided if at all possible.
Jack,
Shawn is absolutely correct - as an FAA policy letter explained some time ago. It is only advisory material for Part 27 helicopters
We may not like it (and in Europe at present it is alleviated) but that is a fact. It is alleviated for offshore operations and when taking off over water by FAR 91.9(d).
It has never been fully explained to me exactly how the take-off gradient -published in the AC 150/5390-2C - of 8:1 can be flown (other than in PC1) whilst staying outside the HV diagram. Double standards come to mind.
I have been reluctant to comment about this accident because performance and power management was so comprehensively flawed. At the very least, HOGE power should have been available.
From a distant memory, the reduction in TBO for the availability of 140-2 power limits are contained within the maintenance manual.
There should have been no doubt in anyone's mind that these were operations with exposure to an engine-failure (the probability of such being widely known); what perhaps the US Forestry Service didn't know was that, without HOGE being available, exposure was possible even with two engines operating.
The take-off power limits are quite clearly stated in the RFM - that these were exceeded routinely came as quite a shock to those of us who did not expect this in commercial operations.
Jim
Shawn is absolutely correct - as an FAA policy letter explained some time ago. It is only advisory material for Part 27 helicopters
We may not like it (and in Europe at present it is alleviated) but that is a fact. It is alleviated for offshore operations and when taking off over water by FAR 91.9(d).
It has never been fully explained to me exactly how the take-off gradient -published in the AC 150/5390-2C - of 8:1 can be flown (other than in PC1) whilst staying outside the HV diagram. Double standards come to mind.
I have been reluctant to comment about this accident because performance and power management was so comprehensively flawed. At the very least, HOGE power should have been available.
From a distant memory, the reduction in TBO for the availability of 140-2 power limits are contained within the maintenance manual.
There should have been no doubt in anyone's mind that these were operations with exposure to an engine-failure (the probability of such being widely known); what perhaps the US Forestry Service didn't know was that, without HOGE being available, exposure was possible even with two engines operating.
The take-off power limits are quite clearly stated in the RFM - that these were exceeded routinely came as quite a shock to those of us who did not expect this in commercial operations.
Jim
Last edited by JimL; 6th Feb 2013 at 13:39.
So, for the purposes of clarity for onlookers in the industry, can I confirm the following:
There is an ENGINE issue, in that civvy CT58's have not been modded (fuel filters) in line with the mil mod done many many years ago. This is a KNOWN problem and no-one in the (civvy) industry has seen fit to elevate this issue?
There is an operator issue where Carson (allegedly) have fiddled the maths w.r.t. AUM and Take Off performance.
There is a conflict of interest within the investigating team (NTSB), who 'appear' to be derelict in their duty?
God help the victims family in trying to negotiate this cluster F*ck.
Are there S61's still flying around with these pre mod (C58) engines?
Are the company: Carson (re-incarnate) still operating? And if so, are they still up to their old tricks?
There is an ENGINE issue, in that civvy CT58's have not been modded (fuel filters) in line with the mil mod done many many years ago. This is a KNOWN problem and no-one in the (civvy) industry has seen fit to elevate this issue?
There is an operator issue where Carson (allegedly) have fiddled the maths w.r.t. AUM and Take Off performance.
There is a conflict of interest within the investigating team (NTSB), who 'appear' to be derelict in their duty?
God help the victims family in trying to negotiate this cluster F*ck.
Are there S61's still flying around with these pre mod (C58) engines?
Are the company: Carson (re-incarnate) still operating? And if so, are they still up to their old tricks?
TC,
Can you tell us more about this "Conflict of Interest"?
Also, are you referring to the Mod that changes the 40 Micron filter to the 10 Micron filter?
There is a conflict of interest within the investigating team (NTSB), who 'appear' to be derelict in their duty?
Also, are you referring to the Mod that changes the 40 Micron filter to the 10 Micron filter?
The Emergency Throttle for No. 2 was found in the partially opened position. Bill Coultas and a second eyewitness confirm that he was attempting to open the No. 2 Emergency Throttle after he saw the torque split on the gauges.
The only reason to do so was a concern by the flight crew with fuel.
The Emergency Throttles are gated and require significant force to move to an open position. Bill Coultas testified they lost power and noted the loss of
rotor speed before they hit any trees.
The only reason to do so was a concern by the flight crew with fuel.
The Emergency Throttles are gated and require significant force to move to an open position. Bill Coultas testified they lost power and noted the loss of
rotor speed before they hit any trees.
What am I missing here?
Did that statement mean to say "fuel flow to the engine" or something else?
I find interesting both the NTSB report, and the criticisms of same.
EDIT:
Apologies for any confusion. The quoted text I put in this post is from point number 9 in post #20 of this thread.
That post cited a number of criticisms of the NTSB report.
9) The sound spectrum analysis is the only "quantitative" data for the conclusion that the No. 2 engine had not failed. Absent this GE/Sikorsky analysis, all of the NTSB conclusions are speculation.
Objective facts supporting an engine issue include the No. 2 torque gauge found post accident with a "split" of 30% from No. 1.
The NTSB theorized this could be from a power loss but wiring schematics show this to be an A/C powered gauge that would have frozen with a sudden loss of power, not wound down.
Even if it had been a DC powered gauge, there would not have been a split: both gauges would have wound down to zero torque.
The Emergency Throttle for No. 2 was found in the partially opened position. Bill Coultas and a second eyewitness confirm that he was attempting to open the No. 2 Emergency Throttle after he saw the torque split on the gauges.
The only reason to do so was a concern by the flight crew with fuel.
The Emergency Throttles are gated and require significant force to move to an open position. Bill Coultas testified they lost power and noted the loss of rotor speed before they hit any trees.
Objective facts supporting an engine issue include the No. 2 torque gauge found post accident with a "split" of 30% from No. 1.
The NTSB theorized this could be from a power loss but wiring schematics show this to be an A/C powered gauge that would have frozen with a sudden loss of power, not wound down.
Even if it had been a DC powered gauge, there would not have been a split: both gauges would have wound down to zero torque.
The Emergency Throttle for No. 2 was found in the partially opened position. Bill Coultas and a second eyewitness confirm that he was attempting to open the No. 2 Emergency Throttle after he saw the torque split on the gauges.
The only reason to do so was a concern by the flight crew with fuel.
The Emergency Throttles are gated and require significant force to move to an open position. Bill Coultas testified they lost power and noted the loss of rotor speed before they hit any trees.
If in shortening the phrasing I changed the meaning I hang my head in shame.
Last edited by Lonewolf_50; 6th Feb 2013 at 17:01.
I found this article that refers to four crashes of S-61's that have involved
Input Clutch failures and reports a survivor said he heard unusual noises that when described could point to a possible Clutch Failure.
A Clutch failure would explain a Torque Split and maybe the use of an Emergency Throttle.
The article says Sikorsky changed the TBO for the Clutch Units by half....from 1,000 hours to 500 hours and put in place a requirement to change the units after 7,500 lifts while logging or hauling water buckets.
NTSB releases documents related to crash that killed seven Oregon firefighters | OregonLive.com
Another article that talks about the NTSB Report and the conflict between the NTSB and the FAA. One of the things the FAA did not do was provide the NTSB information contained in letters written to the FAA by two Carson Pilots which reported Carson may have been intentionally providing false weight data. The FAA did not release the information until a year after the crash and only after the NTSB had asked for documents from all interested parties.
http://wildfiretoday.com/2010/12/08/...icopter-crash/
Input Clutch failures and reports a survivor said he heard unusual noises that when described could point to a possible Clutch Failure.
A Clutch failure would explain a Torque Split and maybe the use of an Emergency Throttle.
The article says Sikorsky changed the TBO for the Clutch Units by half....from 1,000 hours to 500 hours and put in place a requirement to change the units after 7,500 lifts while logging or hauling water buckets.
NTSB releases documents related to crash that killed seven Oregon firefighters | OregonLive.com
Another article that talks about the NTSB Report and the conflict between the NTSB and the FAA. One of the things the FAA did not do was provide the NTSB information contained in letters written to the FAA by two Carson Pilots which reported Carson may have been intentionally providing false weight data. The FAA did not release the information until a year after the crash and only after the NTSB had asked for documents from all interested parties.
http://wildfiretoday.com/2010/12/08/...icopter-crash/
Last edited by SASless; 6th Feb 2013 at 17:20.
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Shawn
from SK61L/N RFM, Category A H-V:
Category B H-V:
the question would be, is the operation in question in line with an exemption? I would have to think about the answer and do a little research.
SAS asks about public use, which is a US regulatory issue I am unfamiliar with.
SAS:
Yes. Okanagan was combined with Ranger and Sealand when bought which created Canadian Helicopters, eventually to evolve into CHC (which is no longer Canadian at all). I haven't met many Okkie guys who thought it was a good thing.
Gordy, the 15 points you quoted are interesting, but again they come from a lawyer, and show similar unfamiliarity with the 61 that the NTSB report did.
I went back to look at the CVR transcript and see no indication whatsoever from either pilot that there was a tourque split or that either of them was initiating emergency throttle usage. As far as the red handle being difficult to move, it gets bumped out of the detent easily and could easily be moved in a crash sequence.
This is an old airframe, there are no computers controlling the engines. When the engine is topped, the fuel flow is physically limited to provide maximum OEI (topped Ng) power and no more. If an engine fails, one need not limit the use of the remaining engine with collective, as it has already been 'topped' and one can just fly the Nr.
Using topping (OEI power) should not be normal practice for take-off just like pulling to the tourque limiter in a 212 should not be done.
Nothing is ever mentioned about the machine being operated within the HV curve, which for a Part 29 helicopter with more than 9 passengers, is a limitation.
A limitation - something that is not permitted.
The rate of rotor RPM droop is also pretty consistent throughout, and also consistent with the rotor RPM droop in the previous takeoffs...
A limitation - something that is not permitted.
The rate of rotor RPM droop is also pretty consistent throughout, and also consistent with the rotor RPM droop in the previous takeoffs...
This curve does not apply to vertical operations or elevated heliport edge procedures...
4. When conducting Category "B" rotorcraft external load operations, this curve does not constitute a limitation.
SAS asks about public use, which is a US regulatory issue I am unfamiliar with.
SAS:
Oleary,
I thought Okanagan grew into CHC...or am I mistaken in thinking that.
I thought Okanagan grew into CHC...or am I mistaken in thinking that.
Gordy, the 15 points you quoted are interesting, but again they come from a lawyer, and show similar unfamiliarity with the 61 that the NTSB report did.
I went back to look at the CVR transcript and see no indication whatsoever from either pilot that there was a tourque split or that either of them was initiating emergency throttle usage. As far as the red handle being difficult to move, it gets bumped out of the detent easily and could easily be moved in a crash sequence.
This is an old airframe, there are no computers controlling the engines. When the engine is topped, the fuel flow is physically limited to provide maximum OEI (topped Ng) power and no more. If an engine fails, one need not limit the use of the remaining engine with collective, as it has already been 'topped' and one can just fly the Nr.
Using topping (OEI power) should not be normal practice for take-off just like pulling to the tourque limiter in a 212 should not be done.
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Even if it had been a DC powered gauge, there would not have been a split: both gauges would have wound down to zero torque.
edited to add: all these 'reports' appear to be speculative efforts to muddy the issue
Last edited by pilot and apprentice; 6th Feb 2013 at 18:00.
SASless: conflict of interest because the wife of the NTSB investigator was responsible for the security of the parts (that have gone missing).
Secondly the Materials report caused the NTSB to shift the investigation to the paperwork discrepancies (Carson) and away from the engine fuel control issue (and the missing parts). Don't you think the NTSB were getting hot under the collar about these (missing) parts?
The mod that changed the 40 micron to the 6 micron filter undertaken by the mil appears 'not' to have been undertaken by this operator on these engines?
Have the fuel control modules/units for these engines ever been found or stripped and investigated??
Secondly the Materials report caused the NTSB to shift the investigation to the paperwork discrepancies (Carson) and away from the engine fuel control issue (and the missing parts). Don't you think the NTSB were getting hot under the collar about these (missing) parts?
The mod that changed the 40 micron to the 6 micron filter undertaken by the mil appears 'not' to have been undertaken by this operator on these engines?
Have the fuel control modules/units for these engines ever been found or stripped and investigated??
Gordy, the 15 points you quoted are interesting, but again they come from a lawyer, and show similar unfamiliarity with the 61 that the NTSB report did.
The families, through Anderson, would like to make the following facts public:
The NTSB report is sobering.
Thought on working at the margins of performance. While the report raises a delicate point about "winds light and variable" that influenced the HH-60 crash and may have in some ways influenced this mishap, my memory has caused me to ponder a different point. (Not gonna chase the 10 micron filters down the rabbit hole ...)
Some years ago, when I flew two engine helicopters, and did training flights doing external loads, confined area landings, and max performance takeoffs, we always had to do the following before attempting any of the maneuvers that might get us close to the margins. There were even a few actual missions I flew from the deck of a ship, fully loaded on hot days with no wind, where we did some performance checks on deck and then called up to the bridge to ask for more speed so I'd be able to take off. (The bickering with ship drivers I won't get into)
To find out what we had actually avaialable, we'd put one engine in idle, pull until two percent droop with the other engine. Record Torque and Ng. Return engine to fly. Do the same for the other engine. Took very little time. You thus had, in situ, a known performance benchmark of how much power you had available.
You also compared that to what you computed pre flight. The delta was sometimes instructive.
Anyway, I may have missed it in the report, but that little check, or something very similar, may or may not be a standard check for that company that crews do before take off when you are doing confined area landings in the environment these gents were flying in.
@ pilot and apprentice: thanks for your points on Emergency fuel control, and a few other points.
Thought on working at the margins of performance. While the report raises a delicate point about "winds light and variable" that influenced the HH-60 crash and may have in some ways influenced this mishap, my memory has caused me to ponder a different point. (Not gonna chase the 10 micron filters down the rabbit hole ...)
Some years ago, when I flew two engine helicopters, and did training flights doing external loads, confined area landings, and max performance takeoffs, we always had to do the following before attempting any of the maneuvers that might get us close to the margins. There were even a few actual missions I flew from the deck of a ship, fully loaded on hot days with no wind, where we did some performance checks on deck and then called up to the bridge to ask for more speed so I'd be able to take off. (The bickering with ship drivers I won't get into)
To find out what we had actually avaialable, we'd put one engine in idle, pull until two percent droop with the other engine. Record Torque and Ng. Return engine to fly. Do the same for the other engine. Took very little time. You thus had, in situ, a known performance benchmark of how much power you had available.
You also compared that to what you computed pre flight. The delta was sometimes instructive.
Anyway, I may have missed it in the report, but that little check, or something very similar, may or may not be a standard check for that company that crews do before take off when you are doing confined area landings in the environment these gents were flying in.
@ pilot and apprentice: thanks for your points on Emergency fuel control, and a few other points.
Last edited by Lonewolf_50; 6th Feb 2013 at 19:23.
A simple Hover Power Check should have prevented this accident as would have using the British style Confined Area Takeoff technique of ascending to the necessary height to clear your barriers THEN translating forward. The Crew being US Army trained and checked by FAA/USFS pilots whose organizations use the same techniques as do the US Military (thinking US Army) actually, uses a different technique of a forward acceleration climbing to clear the barriers by the same safe margin the British do.....the difference is using the British method allows you to discover you do not have the necessary power while still over your takeoff point. As this was from a ridge line with some trees in the takeoff path despite the ground steeply dropping away.
The LZ was dusty, and had been watered down between the first and last flights, which may have played a role in the decision not to do the Hover Check first.
A Torque split with both engines at Topping would normally produce a Split in Torque indications as previously noted by others. As the CVR transcript did not mention any comment about a split and the CVR analysis did not mention any decrease in Engine or Transmission sounds that would indicate any kind of engine malfunction that would have resulted in Tonal or Frequency changes, we have to assume the Engines were operating normally as did the NTSB.
The LZ was dusty, and had been watered down between the first and last flights, which may have played a role in the decision not to do the Hover Check first.
A Torque split with both engines at Topping would normally produce a Split in Torque indications as previously noted by others. As the CVR transcript did not mention any comment about a split and the CVR analysis did not mention any decrease in Engine or Transmission sounds that would indicate any kind of engine malfunction that would have resulted in Tonal or Frequency changes, we have to assume the Engines were operating normally as did the NTSB.
SASless, at the risk of speculation and getting chewed out by those who know the pilots and the S-61 better than I do ...
If you can't hover (HOGE), you'll droop as you try to get to that high hover, so you then descend back down to your spot. Dump some payload, try again?
That's the essence of the British technique you mentioned, right?
I won't comment on how the Army trains helo pilots. I do know that a max performance takeoff from a confined area required you to be clear of obstacles before attempting transition to fwd flight. It was certainly a crew coordination drill, with C/P calling torques and crewman calling clearance.
What you seem to suggest happened is (and after I looked at the picture of the crash site, I surely scratched my head a bit) that the crew tried to get some lifties from forward motion, out of ground effect, before they were clear of the tree tops.
Do I read you correctly?
If you can't hover (HOGE), you'll droop as you try to get to that high hover, so you then descend back down to your spot. Dump some payload, try again?
That's the essence of the British technique you mentioned, right?
I won't comment on how the Army trains helo pilots. I do know that a max performance takeoff from a confined area required you to be clear of obstacles before attempting transition to fwd flight. It was certainly a crew coordination drill, with C/P calling torques and crewman calling clearance.
What you seem to suggest happened is (and after I looked at the picture of the crash site, I surely scratched my head a bit) that the crew tried to get some lifties from forward motion, out of ground effect, before they were clear of the tree tops.
Do I read you correctly?
We do not know what the Crew's thoughts were or perhaps can know exactly what kind of profile they had in mind.
The takeoff point was a ridge line, dusty, LZ with sloping ground before them but with some trees as barriers. We might be able to figure out how high the trees were and that kind of thing by going back to the NTSB Report where they plotted the impact height on the tree and all that data.
You are exactly correct when you state....if you run out of power...and the Nr Droops ....and you have not rotated forward....rejecting the take off is easy....that being a vertical descent back to your takeoff position that is still right under you.
We also know that a Takeoff from the ground provides better performance as compared to a take off started from a Hover.
The CVR recordings seem to indicate that is the profile used....that being a Take off from the Ground with no Hover Power Check done beyond considering weight and balance data, OAT, and recollection of the previous two takeoffs from the first two sorties from that site.
If that is the case...no actual hovering of the aircraft to confirm what power the aircraft was demanding and what reserve was available...then in my view the Crew made a fatal mistake that day.
To be fair....one would really need to be in the cockpit...and seeing what lay before the crew to fully grasp the situation. Just how high were the barriers, how steep was the decline in terrain, did they think they would be able to trade height for airspeed as is done from a ridge line if there is sufficient terrain clearance, and all those considerations.
It is a dead certain fact....If you do not do a Hover Power Check which allows you to confirm handling and power....you have no chance to actually confirm the performance of the aircraft. Old Pilots get that way by being careful in how they go about their business and a hover check is the very insurance one can have. Guessing wrong can prove to be a serious problem.
As they drooped Nr on the earlier takeoffs, that should have been a clue.
I firmly beleive that over time they had become used to seeing some droop on takeoffs especially if the company had the culture it did about using over spec engines as an excuse to carry more weight. Add in the crew being unaware of the bogus Weight data provided by the company and compounded by the false performance data as well. I see them falling into a trap.
They should have been doing a Hover Power check for each takeoff as a good safety habit.
Let's open up another bucket of worms about the FAA and USFS mindsets.
Should the Industry and the USFS and FAA start using Restricted Weights in consideration of OEI operations should an engine fail?
What kind of performance would this passenger carrying aircraft have had if it had experienced an engine failure during the take off, cruise, and landing? Is the FAA supposed to require Large Helicopters to operate in compliance with Part 29 performance standards?
Right now....if those large aircraft hauling passengers are not doing so....are they in violation of Part 29?
Does Safety for the Passengers not mandate they do?
The takeoff point was a ridge line, dusty, LZ with sloping ground before them but with some trees as barriers. We might be able to figure out how high the trees were and that kind of thing by going back to the NTSB Report where they plotted the impact height on the tree and all that data.
You are exactly correct when you state....if you run out of power...and the Nr Droops ....and you have not rotated forward....rejecting the take off is easy....that being a vertical descent back to your takeoff position that is still right under you.
We also know that a Takeoff from the ground provides better performance as compared to a take off started from a Hover.
The CVR recordings seem to indicate that is the profile used....that being a Take off from the Ground with no Hover Power Check done beyond considering weight and balance data, OAT, and recollection of the previous two takeoffs from the first two sorties from that site.
If that is the case...no actual hovering of the aircraft to confirm what power the aircraft was demanding and what reserve was available...then in my view the Crew made a fatal mistake that day.
To be fair....one would really need to be in the cockpit...and seeing what lay before the crew to fully grasp the situation. Just how high were the barriers, how steep was the decline in terrain, did they think they would be able to trade height for airspeed as is done from a ridge line if there is sufficient terrain clearance, and all those considerations.
It is a dead certain fact....If you do not do a Hover Power Check which allows you to confirm handling and power....you have no chance to actually confirm the performance of the aircraft. Old Pilots get that way by being careful in how they go about their business and a hover check is the very insurance one can have. Guessing wrong can prove to be a serious problem.
As they drooped Nr on the earlier takeoffs, that should have been a clue.
I firmly beleive that over time they had become used to seeing some droop on takeoffs especially if the company had the culture it did about using over spec engines as an excuse to carry more weight. Add in the crew being unaware of the bogus Weight data provided by the company and compounded by the false performance data as well. I see them falling into a trap.
They should have been doing a Hover Power check for each takeoff as a good safety habit.
Let's open up another bucket of worms about the FAA and USFS mindsets.
Should the Industry and the USFS and FAA start using Restricted Weights in consideration of OEI operations should an engine fail?
What kind of performance would this passenger carrying aircraft have had if it had experienced an engine failure during the take off, cruise, and landing? Is the FAA supposed to require Large Helicopters to operate in compliance with Part 29 performance standards?
Right now....if those large aircraft hauling passengers are not doing so....are they in violation of Part 29?
Does Safety for the Passengers not mandate they do?
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Gordy, the 15 points you quoted are interesting, but again they come from a lawyer, and show similar unfamiliarity with the 61 that the NTSB report did.
The points were not made by the attorney---he just spoke the words.
Quote:
Quote:
The families, through Anderson, would like to make the following facts public:
Gordy, the 15 points you quoted are interesting, but again they come from a lawyer, and show similar unfamiliarity with the 61 that the NTSB report did.
The points were not made by the attorney---he just spoke the words.
Quote:
Quote:
The families, through Anderson, would like to make the following facts public:
=================
SAS,
Should the Industry and the USFS and FAA start using Restricted Weights in consideration of OEI operations should an engine fail?
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Regarding droop in the 61: the Nr in the 61 isn't static or rigidly governed. It is controlled by the non-flying pilot (as is Q matching) by manipulating the throttles. In a normal t/o the throttles are full forward, or full forward then Q's matched. Nr will reduce as power required increases. Ng, Q and T5 must be observed to prevent exceeding limits. If the pilot does not restrict his power demands the engine will continue to match them until topping is reached.
Again, progressive droop is normal. Exceeding limits is not. Sorry for repeating so much info but I wanted the explanation to be clear.
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Thanks Lonewolf.
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BTW: The 61 is an elegant old girl. My favorite (perhaps because i missed my chance at a tandem :-) )
T-58 at Topping
Just a note about this:
Topping on this engine is an Ng limit mechanical adjustment. The maintenance test pilot and crew make an adjustment using the NG topping screw to result in a T5 of 721-727 as I recall the topping T5 limit range for 2.5 min power.
At the conditions existant for this accident, neither the NG physical limit nor the torque value limit would have been reached before reaching the T5 limit.
Thus when lifting to a hover, the pilot can get a good idea of his margin by looking at T5 and seeing how much margin he has between where the T5 is, and the 721 number. He knows that at 721, increasing collective produces no more power, and only results in Nr droop.
I do recall some ambient condition rules whereby if the operating area conditions change by so much ( altitude/temperature ) then maintenance should recheck/ reset topping, but if I recall the accident report, engine topping had been checked fairly recently.
Topping on this engine is an Ng limit mechanical adjustment. The maintenance test pilot and crew make an adjustment using the NG topping screw to result in a T5 of 721-727 as I recall the topping T5 limit range for 2.5 min power.
At the conditions existant for this accident, neither the NG physical limit nor the torque value limit would have been reached before reaching the T5 limit.
Thus when lifting to a hover, the pilot can get a good idea of his margin by looking at T5 and seeing how much margin he has between where the T5 is, and the 721 number. He knows that at 721, increasing collective produces no more power, and only results in Nr droop.
I do recall some ambient condition rules whereby if the operating area conditions change by so much ( altitude/temperature ) then maintenance should recheck/ reset topping, but if I recall the accident report, engine topping had been checked fairly recently.
Last edited by JohnDixson; 9th Feb 2013 at 00:49. Reason: Additional wording
When we talk Nr droop here....we are concerned with droop below Normal Nr operating RPM are we not. The Normal droop seen is not the issue...but rather abnormal droop below the Minimum Power On Nr limit is what matters.