Engine failure video
Of course it’s easy to say that this was ‘well done’ as everyone seems to agree but surely the most important thing to consider after every flight is, “what mistakes did I make and how can avoid them next time”. Or, “is there anything I could have done better”? Backslapping is positive and of course more sociably acceptable but it’s not the best way of improving performance, that’s of course if you want to improve your performance!
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Well. Thanks all. You may be surprised to hear that I don't regret starting this thread, even if it made me look like a prat.
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
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Well. Thanks all. You may be surprised to hear that I don't regret starting this thread, even if it made me look like a prat.
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
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How about this one - slow below best glide speed to steepen the approach angle!?
Never taught it to my students. But tried it a few times on my own and worked like magic.
Discuss.
Never taught it to my students. But tried it a few times on my own and worked like magic.
Discuss.
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How about this one - slow below best glide speed to steepen the approach angle!?
My "no" is supported by the fact that this is not an approved training nor operational procedure anywhere. And, as correctly mentioned, it puts the plane is a regime of flight where it will be necessary to accelerate it before it can be safely flared for a landing. Doing this would be similarly unsafe as a prolonged climb at Vx, where there is no obstacle to clear. If the engine stops, you have to just up precious altitude gliding to accelerate to best glide speed (or probably a little faster) so you can successfully flare to arrest your rate of descent. Speed is safety!
A review of the concept of a "height/velocity" or "Avoid" curve for a helicopter, and how that actually applies to an airplane as well will support this understanding.
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Doesn’t matter how well you do in training the first time somebody shoots at you in anger changes your perspectives....
...So it’s fairly arrogant to state how good you are in a training environment if you don’t know how difficult the real thing is.
Its like being a black belt in no contact Karate.
...So it’s fairly arrogant to state how good you are in a training environment if you don’t know how difficult the real thing is.
Its like being a black belt in no contact Karate.
Well. Thanks all. You may be surprised to hear that I don't regret starting this thread, even if it made me look like a prat
Ex-helicopter pilots seem to like it!
Mog
PS Stall is c35kts!
Last edited by Mogwi; 9th Nov 2021 at 08:40. Reason: Add PS
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Once the aircraft has let you down - in this case with engine failure - the sole aim thereafter is to preserve life.
The aeroplane surviving intact is a welcome bonus.
It is good to analyse these things - learning takes place.
lsh
The aeroplane surviving intact is a welcome bonus.
It is good to analyse these things - learning takes place.
lsh
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As you found out, it works but there are a couple of traps to be wary of. First, your margin from the stall is reduced so if you flare from this speed you may stall. Associated with that, when you flare your speed will reduce and as you are below min drag speed your rate of descent will increase and you can get a heavy landing. However, if at a suitable height you dive to regain the best glide speed before you flare then it can work well, and I suspect that this is what you did? But it can go wrong and result in a heavy landing or stall.
As for the flare, a slow transition back to normal flare speed. Or a seat of the pants flare from a lower speed. Either works if you're one with your airplane. A bad idea probably for a new inexperienced student.
My "no" is supported by the fact that this is not an approved training nor operational procedure anywhere. And, as correctly mentioned, it puts the plane is a regime of flight where it will be necessary to accelerate it before it can be safely flared for a landing.
It is possible to sit high on base leg at 40kts until the picture/height looks right, then make a dirty dive to Vmd and turn finals. It does require practice and judgement and I prefer to use S turns and aggressive side slip.
Been many years no since I even touched an SEP, so I might not be the best to comment. However, proper energy management is a very rewarding thing in airliner. Maybe the reason why I take good interest in this thread.
Last edited by 172_driver; 9th Nov 2021 at 13:48.
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At say 50 kts and full flaps in a C172, you sit comfortably well above a known stall speed
I am wondering if you could call it "approved". If so, by whom?
I'm less expert at who approves training curriculums, but I'm certain that the national authority does - they won't issue a license to a candidate who has not been recommended against the training standards. Instructors must train students to the curriculum, and not in contravention of the airplane POH. But that's the legality, it's the physics of power idle/off flight in power planes which is more important:
Again, referencing the 172S, yes, you can sit high on the approach, full flaps, descending under control at 50 KIAS, with power idle (or a failed engine) so power is not being considered any more. Cessna tells you that for that phase of flight, you should be flying at 65 KIAS (incidentally, Cessna also tells us that "maximum glide" will be achieved at 68 KIAS - flaps up, I'm sure). I don't have information for full flaps glide, but I'm sure we'll all agree that it's much less distance per altitude than flaps up. So you're going down more steeply, and at a slower airspeed than the POH values. That's okay, as long as you can recover it to a zero rate of descent when you need to. It is a pilot's ultimate goal to arrive back to earth at a zero rate of descent! As you are descending (at a steady rate, we'll presume), you are going to have to accelerate upward from that descent path to momentarily arrest your rate of descent to zero (to prevent impact). Accelerating takes energy, and all the energy you have to work with is airspeed only, as the engine is not available to you for power. So Cessna tells you you should be at 65 KIAS, but you've chosen to fly at 50 KIAS, and stall is at 40 KIAS. When you see the ground getting really close, you're going to pull, to achieve that zero rate of descent which will allow the plane to be reused. Cessna has demonstrated that from 65 KIAS, a pilot of average skill can exchange that 25 knot excess airpseed into a zero RoD before the stall. Oh, by the way, from that steeper descent angle, it will require a greater acceleration upward (G) than normal to flare. Slightly greater G requirement means that stall speed goes up when you pull. Cessna test pilots have learned the same lesson I've learned during flight testing, that the ten knot excess speed above stall on approach is just not enough.
Or... you glide the proper speed as per the POH. If you're too high/fast, slip. You can slip at any speed, modulate it from a little slip to more, and recover in a second, with no change in speed. And, if you're wanting to add drag to get down faster, fly a higher airspeed, drag increases as a square of the speed. And, sideslips are approved in the flight manual, and the training material.
Flying slow approaches, or simply flying slowly at low altitude should make your Spidey senses tingle. Some of the scariest flight testing I have done has been demonstrating a landing from a sudden power loss at 50 feet (a design requirement) from speeds slower than "normal" for the plane (Vy). If you want to safely prove this to yourself, do the following: Climb up into your practice area, at least as high as you'd practice stalls from. Choose a "hard deck" altitude several thousand feet up - a round number altitude will make it easier. Stabilize a slow cruise flight 150 feet higher than that hard deck altitude, at the glide speed and flap setting you'd like to evaluate. Close the throttle rapidly, and enter a glide at your proposed speed. As you approach the hard deck as indicated on your altimeter, pull to arrest your descent momentarily at that altitude, prepared to recover a gentle stall there if it does. Were you able to pause the altimeter pointer at that altitude? If so, it's probably a good speed. If you pulled and stalled, dropping through that altitude, it was too slow, you did not retain enough reserve energy in the plane, to spend arresting the descent before you hit.
From observations I have made during testing, I believe that Cessna's lawyers had a role in choosing the climb and glide speeds for their airplanes - probably Cessna's lawyers have learned the hard way!
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Pilot DAR,
As you mentioned it, I had to check Vso for the Cessna I had in mind - 172R. Vso is 33 kts. Then I checked the 172S. Vso is 40 kts. I thought it was the same airframe with a slightly higher power engine and climb optimised propeller?
As for the rest I am humble to your experience in flight testing. My suggestion of slowing below best glide to steepen the approach angle was not to maintain it until flare. Rather to realise that energy management by speed is another tool in the toolbox. Use it until back on profile, until you've got the right picture back. I have seen some pretty scary forward slips as the pilot doesn't lower the nose to match the increased drag. That manoeuvre in itself introduces some risks.
As you mentioned it, I had to check Vso for the Cessna I had in mind - 172R. Vso is 33 kts. Then I checked the 172S. Vso is 40 kts. I thought it was the same airframe with a slightly higher power engine and climb optimised propeller?
As for the rest I am humble to your experience in flight testing. My suggestion of slowing below best glide to steepen the approach angle was not to maintain it until flare. Rather to realise that energy management by speed is another tool in the toolbox. Use it until back on profile, until you've got the right picture back. I have seen some pretty scary forward slips as the pilot doesn't lower the nose to match the increased drag. That manoeuvre in itself introduces some risks.
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Well. Thanks all. You may be surprised to hear that I don't regret starting this thread, even if it made me look like a prat.
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
Next time, I would be less willing to criticize, even though criticism does not imply that I think I could have done better. In fact, as soon as I saw the video, I had a nightmare vision of me frozen at the controls, having come in high, seeing the runway rapidly disappearing and not having the brain bandwidth to do anything about it. Discussions like this might help me to visualize sideslipping to save the day. I have used sideslipping, without flaps and early in the approach in practice engine fails, but I don't trust that I would have had the mental ability to pull that trick out of the box with flaps down and 50 feet above the runway.
Thanks!
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172R. Vso is 33 kts. Then I checked the 172S. Vso is 40 kts
I've done lots of stall testing in many models of Cessnas, including lots of mods like STOL kits, floats and external loads, and some AoA system set ups. CAS becomes a pretty important factor, when you're really getting down to the precision of the stall speed. That's why the POH says that KIAS values are approximate.
Rather to realise that energy management by speed is another tool in the toolbox.
For myself, I find that if there is to be a judgement error during a forced landing, I'd rather see it to be fast/high than slow/low. As the original video shows us, you're better to go off the end at low speed, than crash short (and maybe out of control) at flight speed. My third forced landing (an EFATO) had me a little fast and high - surprise factor, delayed proper action. I came to a stop in the adjoining field about ten feet from the far end fence with full flaps, nose up elevator and brakes applied. No damage, not my proudest airmanship, but better than tangled in the trees at the approach end - and, should it have not worked out, I could state to the insurance company that I had done exactly what the POH and my training had said to do.
Just a quick note re side slipping Cessna's with full flap.
Had an instructor demonstrate a fairly vigorous side slip in a 150. This was over 35 years ago and was to show me how to 'fix up' a stuffed practice forced landing into some paddock.
Lost control at around 200ft, flick rolled and ended up near enough inverted.
After he recovered and during the awkward flight of shame back home I asked what happened...
'No idea' was the reply....
Later on figured out he stalled the fin. It was nasty.
.
Had an instructor demonstrate a fairly vigorous side slip in a 150. This was over 35 years ago and was to show me how to 'fix up' a stuffed practice forced landing into some paddock.
Lost control at around 200ft, flick rolled and ended up near enough inverted.
After he recovered and during the awkward flight of shame back home I asked what happened...
'No idea' was the reply....
Later on figured out he stalled the fin. It was nasty.
.