Flap retraction on Arrow?
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Flap retraction on Arrow?
I fly an Arrow II, fitted with a ‘gear unsafe’ mechanism which, basically, cues the pilot with a warning horn and light when the gear is retracted with flap settings above 10°.
On the Arrow, a max performance take-off is achieved with 25° flap and it is here that my query arises. On short-field operations I prefer to leave the gear down until a safe height is reached and retract flap to the 10° position before pulling the gear up. My reasoning is that the aircraft shouldn’t be deliberately flown with a warning horn (which is identical to the stall warning) and light blaring at such a critical phase of flight.
On a recent annual check-ride with an instructor, I was ticked off for not getting the gear up immediately after take-off. He insisted that flying with the warnings was more acceptable than the extra drag caused by the dangling gear. (My post-flight counter argument that less powerful fixed-gear Cherokees manage this quite well fell on deaf ears.)
Any opinions?
HP
On the Arrow, a max performance take-off is achieved with 25° flap and it is here that my query arises. On short-field operations I prefer to leave the gear down until a safe height is reached and retract flap to the 10° position before pulling the gear up. My reasoning is that the aircraft shouldn’t be deliberately flown with a warning horn (which is identical to the stall warning) and light blaring at such a critical phase of flight.
On a recent annual check-ride with an instructor, I was ticked off for not getting the gear up immediately after take-off. He insisted that flying with the warnings was more acceptable than the extra drag caused by the dangling gear. (My post-flight counter argument that less powerful fixed-gear Cherokees manage this quite well fell on deaf ears.)
Any opinions?
HP
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Lets start with a look at "safe height". Under normal circumstances, you would tend to retract the gear once there is no realistic possibility of putting the aircraft back down again. If this really is a short strip requiring a maximum performance take-off, the chances are that this point will be reached fairly rapidly after the wheels leave the ground. So that eliminates one reason for keeping them down.
After you have taken off, you generally want to gain height. Height does many things for you, including expanding your options in the event of an Engine Failure.
By leaving your gear down, you are decreasing the rate at which you climb, and therefore extending the period of time during which your options are severely limited by an Engine Failure. The fact that Fixed-Gear Cherrytree drivers live with this problem should not cloud your judgement. There is no honour in copying them
The extention of that argument is that when the engine does fail, the last thing you want dangling out of the bottom of your aircraft is the landing gear (note also the problems with the Arrow's auto-extend functionality) Gear kills your glide performance.
I would simply opt to brief your passengers about the possible alarm ahead of departure (which you should do anyway), and get the aircraft cleaned up (flaps and all) at the earliest possible time after take-off. If the terrain permits, get the nose down and speed up to a point at which the flaps can be retracted. We are not talking about many knots in something like an Arrow.
Bear in mind that in addition to height, the other thing you want is speed, and you won't get a lot of that with 25 degrees of flap and gear hanging off you.
-2Donkeys
[This message has been edited by 2Donkeys (edited 28 March 2001).]
After you have taken off, you generally want to gain height. Height does many things for you, including expanding your options in the event of an Engine Failure.
By leaving your gear down, you are decreasing the rate at which you climb, and therefore extending the period of time during which your options are severely limited by an Engine Failure. The fact that Fixed-Gear Cherrytree drivers live with this problem should not cloud your judgement. There is no honour in copying them
The extention of that argument is that when the engine does fail, the last thing you want dangling out of the bottom of your aircraft is the landing gear (note also the problems with the Arrow's auto-extend functionality) Gear kills your glide performance.
I would simply opt to brief your passengers about the possible alarm ahead of departure (which you should do anyway), and get the aircraft cleaned up (flaps and all) at the earliest possible time after take-off. If the terrain permits, get the nose down and speed up to a point at which the flaps can be retracted. We are not talking about many knots in something like an Arrow.
Bear in mind that in addition to height, the other thing you want is speed, and you won't get a lot of that with 25 degrees of flap and gear hanging off you.
-2Donkeys
[This message has been edited by 2Donkeys (edited 28 March 2001).]
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I think that the throtle position may have a part to play in this IE if the throtle is at high power the warning is inhibited......i shall go look at the maintenance manual and report back.
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2Donkeys:— I agree with all you say. (My usual short-field technique is to climb to 300ft AGL, accelerate, retract flap to 10°, gear up, then zero flap, set climb power.)
However, what I’m really asking is whether or not an aircraft should be deliberately flown through a warning, especially at such low level and low speed (the horn in question is indistinguishable from the stall warning). The POH is very vague in this area.
A and C:— We are talking full throttle here. (The a/c doesn’t have that awful gear auto-extend system either).
HP
However, what I’m really asking is whether or not an aircraft should be deliberately flown through a warning, especially at such low level and low speed (the horn in question is indistinguishable from the stall warning). The POH is very vague in this area.
A and C:— We are talking full throttle here. (The a/c doesn’t have that awful gear auto-extend system either).
HP
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Horsepower
If I remember right from my high performance course in the US a few years ago, the Arrow gear creates the highest amount of drag whilst in transit and that operation takes quite a few seconds. (13 or so??)
Therefore I would be with you under the circumstances, with the only difference that I might consider cleaning the wing completely before gear retraction, as it only takes a few seconds to secure the airspeed and set the target climing speed after retracting the second stage of flaps.
If I remember right from my high performance course in the US a few years ago, the Arrow gear creates the highest amount of drag whilst in transit and that operation takes quite a few seconds. (13 or so??)
Therefore I would be with you under the circumstances, with the only difference that I might consider cleaning the wing completely before gear retraction, as it only takes a few seconds to secure the airspeed and set the target climing speed after retracting the second stage of flaps.
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Why 300ft? This seems very high considering short field is often to avoid an obstacle. How many trees are 300 ft tall where you fly from? Once you have cleared any obstacles why continue to climb at max angle and leave the gear and flaps down. why not clean up at a lower height and speed up for a safer climb (increased engine cooling & margin over stall)?
Just a thought.
Just a thought.
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Horsepower
If that is the question you are asking, then the answer is as before - ignore the warning. That warning is not intended for the circumstances you describe, but rather for the poor soul about to land gear up. Presumably that is not a real risk in the circumstances you describe.
Get the gear up once you have a positive rate of climb, and no possibility of landing ahead. Once those conditions are met, and assuming you are at a safe flying speed (negating the earlier point about the drag of gear in transit), get them up and out of the way ASAP.
-2Donkeys
<font face="Verdana, Arial, Helvetica" size="2">
However, what I’m really asking is whether or not an aircraft should be deliberately flown through a warning, especially at such low level and low speed </font>
However, what I’m really asking is whether or not an aircraft should be deliberately flown through a warning, especially at such low level and low speed </font>
Get the gear up once you have a positive rate of climb, and no possibility of landing ahead. Once those conditions are met, and assuming you are at a safe flying speed (negating the earlier point about the drag of gear in transit), get them up and out of the way ASAP.
-2Donkeys
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If you follow the same logic as twin flying, where you raise the gear once there is insufficient runway/field remaining to land on and you have a positive rate of climb, then the earlier posts said it all. Piper made retractable gear aircraft because it made them perform better, and not just in the cruise. If you can reduce drag and improve your climb performance then do so ASAP. The argument that if you are close to the ground and you lose the engine you will not have time to put it down again is a circular one, since if you had put the gear up you would have been higher and therefore would have more time. Ultimately I would suggest it's better to make a controlled belly landing into the middle of your chosen field than hit the near hedge at 70 kts with the gear down! 
300 feet refers I think to flap retraction, so that the tendency to sink or reduce climb performance initially is less critical than at a lower height.
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"Take-off is optional, Landing is mandatory"
300 feet refers I think to flap retraction, so that the tendency to sink or reduce climb performance initially is less critical than at a lower height.
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"Take-off is optional, Landing is mandatory"
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The sink rate on the Arrow with flap at 73 knots is around 700 fpm and gear alone 1100 feet per minute, in the climb away from take off the gear warning alarm is an intermittent beep and the stall warner a steady note, an engine failure at low level should mean leaving the gear down to minimise damage (sink after take off) and higher (200 feet plus) gear away before the flap to reduce drag and increase climb rate, flap retraction at low level should be avoided suddenly dropping the mechanical handbrake type lever will cause the aircraft to drop 200 feet as the lift is dumped.
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Eyeinthesky. Interesting point you made on leaving the gear down in a twin on take-off, until you no longer have enough runway to land ahead on - then retract gear. You need to be careful that you are not painting yourself into a dangerous corner.
By leaving the gear down you are only delaying acceleration to blue line speed and any airborne abort becomes more risky with each passing second.
Also there are no performance figures for most light twins that give you distance needed to get airborne - lose an engine at 100 feet - and abort straight ahead. Therefore it is almost impossible to judge exactly when you have no longer any safe distance to land back on. The situation is exacurbated if it a wet runway and /or night.
Remember that you will be touching down at a relatively high speed with flaps possibly still up, and no anti-skid capability. This all makes for a long roll-out.
There is always going to be a 10-15 second grey area of uncertainty immediately after lift-off which will dictate whether or not you feather and climb out or snap both throttles closed and abort from airborne. Pilot skill and experience plays a great part either way.
Most light twins will reach blue line speed a few seconds after lift-off and providing you have started gear retraction and got the prop feather process underway, then the aircraft should climb single engine if everything is done right. It follows that the best chance of covering your bases is to retract the gear as soon as you have a positive rate of climb after lift off. Do not deliberately delay gear retraction for the reasons given above.
By leaving the gear down you are only delaying acceleration to blue line speed and any airborne abort becomes more risky with each passing second.
Also there are no performance figures for most light twins that give you distance needed to get airborne - lose an engine at 100 feet - and abort straight ahead. Therefore it is almost impossible to judge exactly when you have no longer any safe distance to land back on. The situation is exacurbated if it a wet runway and /or night.
Remember that you will be touching down at a relatively high speed with flaps possibly still up, and no anti-skid capability. This all makes for a long roll-out.
There is always going to be a 10-15 second grey area of uncertainty immediately after lift-off which will dictate whether or not you feather and climb out or snap both throttles closed and abort from airborne. Pilot skill and experience plays a great part either way.
Most light twins will reach blue line speed a few seconds after lift-off and providing you have started gear retraction and got the prop feather process underway, then the aircraft should climb single engine if everything is done right. It follows that the best chance of covering your bases is to retract the gear as soon as you have a positive rate of climb after lift off. Do not deliberately delay gear retraction for the reasons given above.
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Centaurus
The point you make is a good one, although on the kind of runways used by most UK light aviation, it is almost academic. Accelerate stop in my light twin (that is: closing the throttles at Vr and applying maximum effort braking) uses up about 1100 metres at MTOW. On most runways therefore once you've unstuck, you are not likely to land on succesfully and should retract the gear ASAP.
In a light single (to return to the original question), accelerate stop distance is likely to be significantly less and the idea of retracting the gear only once insufficient runway exists becomes more relevant. On a short field though, you are in the same position as a twin, in that you are not likely to be able to get down on the runway remaining once you've lifted off, so getting the gear up becomes a priority.
-2Donkeys
The point you make is a good one, although on the kind of runways used by most UK light aviation, it is almost academic. Accelerate stop in my light twin (that is: closing the throttles at Vr and applying maximum effort braking) uses up about 1100 metres at MTOW. On most runways therefore once you've unstuck, you are not likely to land on succesfully and should retract the gear ASAP.
In a light single (to return to the original question), accelerate stop distance is likely to be significantly less and the idea of retracting the gear only once insufficient runway exists becomes more relevant. On a short field though, you are in the same position as a twin, in that you are not likely to be able to get down on the runway remaining once you've lifted off, so getting the gear up becomes a priority.
-2Donkeys
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Centaurus and 2 donks:
Thanks for your comments. I was assuming, although I didn't make it clear, that you would not even consider retracting the gear until you've reached blue line speed. To do so, irrespective of how short the runway or how dark it is, seems foolhardy in the extreme. We all know that the only way a light twin is going when speed's below blue line and an engine quits and that is down. Past blue line speed if the runway is long enough then you can choose whether to keep your options open by leaving the gear down as you climb away or raise it. I said in my original post that you raise it once there is insufficient runway to land on. That of course means you hope to be able to land AND stop. If you are at 300 feet half way down a 2000m runway then obviously that will be difficult.
We can of course talk about this all day. As some people say, all a light twin does is move the scene of the accident further away....
By the way, have you ever read such a long sentence as juggernaut's??
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"Take-off is optional, Landing is mandatory"
Thanks for your comments. I was assuming, although I didn't make it clear, that you would not even consider retracting the gear until you've reached blue line speed. To do so, irrespective of how short the runway or how dark it is, seems foolhardy in the extreme. We all know that the only way a light twin is going when speed's below blue line and an engine quits and that is down. Past blue line speed if the runway is long enough then you can choose whether to keep your options open by leaving the gear down as you climb away or raise it. I said in my original post that you raise it once there is insufficient runway to land on. That of course means you hope to be able to land AND stop. If you are at 300 feet half way down a 2000m runway then obviously that will be difficult.
We can of course talk about this all day. As some people say, all a light twin does is move the scene of the accident further away....
By the way, have you ever read such a long sentence as juggernaut's??
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"Take-off is optional, Landing is mandatory"
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Just a minor note of caution for anyone new to the Arrow who may follow juggernauts sequence of gear and flap retraction.
There is a little potential trap in that the gear retraction limit speed is somewhat higher than the flap limit [113 to 102 kias, or thereabouts from memory.]
The little devil does accelerate very nicely when the wheels tuck away and there is a bit of a nose down pitch on retraction which tends to aid the process, so for anyone not used to the a/c, the application of some back pressure and a watching eye on the ASI is recommended!
So long as this is done, no probs.
There is a little potential trap in that the gear retraction limit speed is somewhat higher than the flap limit [113 to 102 kias, or thereabouts from memory.]
The little devil does accelerate very nicely when the wheels tuck away and there is a bit of a nose down pitch on retraction which tends to aid the process, so for anyone not used to the a/c, the application of some back pressure and a watching eye on the ASI is recommended!
So long as this is done, no probs.
