Turning back after takeoff
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Turning back after takeoff
Came across this very interesting video in the DownUnder section of PPrune. Sort of refutes pretty much all common wisdom about turnbacks after EFATO.
Aerobatics in California
Thoughts?
Aerobatics in California
Thoughts?
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Google on
rodgers "the impossible turn"
for the theory.
e.g. here
Yes a turnback is clearly possible. It needs a steep bank, yoke back to the onset of stall, and no delay
A long runway and a strong wind can make it very easy, as does height.
A lot of people have been killed doing this; I wonder how many of them tried it in truly impossible conditions and how many were simply afraid to use a steep turn.
rodgers "the impossible turn"
for the theory.
e.g. here
Yes a turnback is clearly possible. It needs a steep bank, yoke back to the onset of stall, and no delay
A long runway and a strong wind can make it very easy, as does height.
A lot of people have been killed doing this; I wonder how many of them tried it in truly impossible conditions and how many were simply afraid to use a steep turn.
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IO, that much is known. What I found interesting in this video is the conclusion they come to, which favours a steep or very steep turn.
Not suggesting to try it, though (other than at altitude, of course).
Not suggesting to try it, though (other than at altitude, of course).
Avoid imitations
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Sounds like this was done with the engine still running at idle.
IIRC RAF procedure (for the Bulldog turnback) was 45 degrees AOB. Minimum gliding speed increased to 80 kts IAS, no less.
IIRC RAF procedure (for the Bulldog turnback) was 45 degrees AOB. Minimum gliding speed increased to 80 kts IAS, no less.
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But as we all know a steep turn gets your load factor up. This increases stall speed. And this is where it unravels most of the time, as the instinct is to keep pulling up to get back to that field with inevitable results: spin and stall.
If you can keep a cool head and not let the stall come up and bite you, then I'm sure it's doable.
This is also the reason one should carry a bit more speed until established on the final. I know, most of us do, but surprisingly many are doing 20-30 degree banks at very close to straight and level stall speeds. This has the potential to bite one day when you have to do a last minute aversive maneuver. A stall in a turn is not that bad at 3000ft. At 500ft it can be deadly.
If you can keep a cool head and not let the stall come up and bite you, then I'm sure it's doable.
This is also the reason one should carry a bit more speed until established on the final. I know, most of us do, but surprisingly many are doing 20-30 degree banks at very close to straight and level stall speeds. This has the potential to bite one day when you have to do a last minute aversive maneuver. A stall in a turn is not that bad at 3000ft. At 500ft it can be deadly.
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Glider pilots are thought to have a plan. You sit at the launch point and decide at what height range you will land ahead, orbit or fly a circuit (however abbreviated). The advantage of this is it takes the “think time” out of the equation. On my turnback I was already at 60deg of bank by the time my brain fully caught up with the problem, but I got it back down ok, just…
The important thing is to not even attempt it unless you have a clear plan, in advance of any issue which might arise in the air.
Rod1
The important thing is to not even attempt it unless you have a clear plan, in advance of any issue which might arise in the air.
Rod1
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Glider pilots are thought to have a plan. You sit at the launch point and decide at what height range you will land ahead, orbit or fly a circuit (however abbreviated). The advantage of this is it takes the “think time” out of the equation. On my turnback I was already at 60deg of bank by the time my brain fully caught up with the problem, but I got it back down ok, just…
Rod1
Rod1
I don't set height ranges because (a) on a winch the altimeter lags and (b) on an aerotow, I could be at 400' but five miles from the airfield.
Agree with the idea though. Have a plan. When you have a launch failure.....execute the plan. And review. Definitely saves several seconds of "oh, what's happening?, I wonder if I should....err, h'mmm..."
There was a study done in the US about turnback versus straight ahead in the event of an EFATO. The conclusion of the study was pilots who turned back had approximately an 8 times higher fatal accident rate than those who just landed straight ahead. I think this is one of those things were you have to be careful when extrapolating what should be possible vs what actually happens when a real world no notice EFATO emergency occurs. It is absolutely possible to make the turn back, but the sad fact is many who have tried it have died in the attempt.
Last edited by Big Pistons Forever; 31st Jan 2011 at 02:03.
Some Interesting Reading
Go to Prof Rogersthen enter the website for:
The Feasibility of Turnback from a Low Altitude Engine Failure During the Takeoff Climb-out Phase by Brent Jett
The complete AIAA (American Institute of Aeronautics and Astronutics) paper that discusses a simulator experiment addressing the turnback after engine failure at low altitude (500 feet) during take-off problem (329k pdf file).
This experimental work was done as a research project at the United States Naval Academy Aerospace Engineering Department during 1981 while Jett was a Midshipman 1/C. I was the Academic Advisor. Professor Bernard Carson contributed to the theoretical part of the research. (I reset the paper and made one or two minor corrections.)
Dave Rogers
The complete AIAA (American Institute of Aeronautics and Astronutics) paper that discusses a simulator experiment addressing the turnback after engine failure at low altitude (500 feet) during take-off problem (329k pdf file).
This experimental work was done as a research project at the United States Naval Academy Aerospace Engineering Department during 1981 while Jett was a Midshipman 1/C. I was the Academic Advisor. Professor Bernard Carson contributed to the theoretical part of the research. (I reset the paper and made one or two minor corrections.)
Dave Rogers
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But as we all know a steep turn gets your load factor up
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Even Svetlana Kapanina would want at least a 1000 feet before considering the turn back. You fly runway heading, aviate navigate then communicate. 30 years since I drove a 172 but the "no turn back" is one of the few things I remember.
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I think it is possible as long as the pilot is fully conversant with the aircraft he/she is flying, notably recognising the onset of a stall. A good reason to have an AoA gauge.
For most of us mere mortals, I think the land ahead option is by far the better choice providing there is somewhere half decent for a forced landing.
For most of us mere mortals, I think the land ahead option is by far the better choice providing there is somewhere half decent for a forced landing.
Surely the deciding factor is how quickly you gain height on departure, and how well your aircraft glides in a turn (Rof D). The bottom line is you need altitude to do a descending gliding 180deg + turn, so if you have a rate of climb that is significantly greater than your rate of descent in the gliding turn you should be okay. Unfortunately few spam cans have a particularily good rate of climb.
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I used to instruct in gliders. Besides having a plan, as was mentioned earlier, glider pilots have the advantage of actually training and practicing the maneuver, which most power pilots don't. It takes some practice to get comfortable with a coordinated steep turn close to the ground, with good speed control. And don't forget it's more than a simple 180 -- the first turn back is actually more than 180 degrees, followed by rolling the other way into a very quick alignment with the runway. When I had an actual rope break, the training kicked in as planned. It's harder to quantify the factors influencing the decision -- a strong headwind on takeoff can make the return trickier, since you'll have a strong quartering wind in the turn and a tailwind on the subsequent landing. Combined with the steeper climb angle in a headwind, you can actually end up too high when you roll out of the turn. I once almost created an over-run situation in training by pulling the release too early in a strong wind. Pilot proficiency, turbulence, and traffic awareness are also factors affecting the decision. If someone behind you has started rolling for takeoff then it won't be fun for either of you if you make that 180. Just because you CAN return doesn't mean you always should. It was just as important to have a straight-ahead option as part of the briefing before takeoff.
Last edited by KMSS; 31st Jan 2011 at 19:54. Reason: clarity, but why are paragraph breaks ignored?
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Memories
My view is to never, ever attempt a turn back. Land straight ahead. John Eckelbar, Flying The Beech Bonaza states that every pilot should learn his airplanes minimum safe turnback altitude and never to try a turnback below that altitude.
He advocates that if high enough, turn at 45 degrees bank at a speed comforably above (30%) the stall speed. That should equal Vy.
However, again, lots of factors - wind, weight, rate of climb, terrain etc. Too many factors - land ahead
He advocates that if high enough, turn at 45 degrees bank at a speed comforably above (30%) the stall speed. That should equal Vy.
However, again, lots of factors - wind, weight, rate of climb, terrain etc. Too many factors - land ahead
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“My view is to never, ever attempt a turn back. Land straight ahead.”
If I had done that I would almost certainly be dead, so as I (and the aircraft) survived and it is a manoeuvre I had done many times in my gliding, I will continue to keep all options open and hope to continue to choose wisely.
Rod1
If I had done that I would almost certainly be dead, so as I (and the aircraft) survived and it is a manoeuvre I had done many times in my gliding, I will continue to keep all options open and hope to continue to choose wisely.
Rod1