What did this guy do wrong?

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yankeeclipper

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Came across this on the Tube; a fuel valve allegedly clogged, but does this look like a panic stall?

 
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Dan Thomas

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Came across this on the Tube; a fuel valve allegedly clogged, but does this look like a panic stall?

YouTube - Destroyed in Seconds - Plane Crash
Tried to stretch the glide by pulling the nose up, hoping the engine would wake up and get him out of there. The result was a pancake landing that's awfully hard on the spine. The experts say that for a ditching, you should set the glide speed and stay well above stall in touchdown so avoid the nose dropping and digging in. See
http://www.equipped.com/ditch.htm#SurvivingaSplashdownhttp://www.equipped.com/ditchtoc.htm

And you'd better have shoulder harnesses. How many are flying without them?

Dan
 

orion

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A stall, especially a tip stall, this low and this slow would have been followed by a nose-over and a lawn-dart type of impact. The wobble here was most likely caused either by the pilot (putting on his shoulder belt?) or by turbulence, but a wobble was all it was since the glide was more or less continuous and under control. If the tip stalled he would not have been able to recover back to level at that low an altitude.

It's highly probable that he was trying for the lake, stretching as much distance out of the glide as possible. Notice the flaps are up - the maximum glide for aircraft is in the clean configuration. But towards the end he was just running out of airspeed and thus the pancake.
 

rtfm

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Fascinating. This is the first time I've actually seen (from the outside) what a stall looks like. I'm fascinated that the plane stalls, dips, recovers, and repeats the process. Quite encouraging - no spin, and not a heck of a lot of height loss, to be honest. The only thing he didn't have going for him was spare height.

From the look of the surrounding area, he didn't have much choice but to extend the glide till he was over water. Coming down in the trees would have been potentially fatal.

But that landing. Ouch!

Duncan
 

Mac790

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Orion said:
A stall, especially a tip stall, this low and this slow would have been followed by a nose-over and a lawn-dart type of impact.
Orion,
Thanks for explanations.

Fascinating. This is the first time I've actually seen (from the outside) what a stall looks like.
Duncan,
Check out this Midget Mustang video, this clip shows approach to a stall, the stall, and a deep stall, you can actually see that plane is falling almost vertically.
http://www.mustangaero.com/images/Midget%20Mustang/stall%20S.MPG

this one is also a "good" example, but this guy had a "little bit" less luck
[video=youtube;ErgpJzcAS6s]http://www.youtube.com/watch?v=ErgpJzcAS6s[/video]

Seb
 
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BBerson

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Just to be clear here. It is impossible to "stretch a glide" by pulling the nose up. He should have lowered the nose to maintain best L/D airspeed. The near stalled mushing airspeed he used will result in a much worse glide angle. At an altitude of about 10 feet you can then stretch the glide a bit but not before.
The lateral instability shown was a result of the high angle of attack. I am surprised that the airplane remained upright, it must have relatively good stall behavior.

Pilots need to avoid pulling back when the engine quits. It is hard to control the tendency to pull back on the stick. For all pilots, I recommend some time in a glider with an instructor. And some gliding instruction in the airplane as well.
BB
 

BBerson

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The ultralight pilot pulled the stick all the way back, clearly visible in the video, and that resulted in dropping almost straight down. He should have pushed the stick forward and flown into the trees with some airspeed in my opinion. The video makes my point about how most pilots will pull back on the stick. I have made the same mistake myself a couple of times. Fortunately, I had only a partial engine failure and was able to maintain altitude in both cases. But the tendency was to pull back.
BB
 

orion

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Yea, one of the aspects of this flight I was trying to describe here was sort of like that of flying behind the power curve - in other words, he was too slow to maintain a good glide, which would have allowed him to flare. His glide was simply too low on energy and there was nothing left to convert to a nice flare maneuver.

The pull back you indicate looks to be like he was trying to clear the trees by a greater distance than he needed to. Even if he skimmed them he might have made a better landing.

But I don't think the pull-back was as dramatic as it might appear. If it was the results would have been much different. One of my customers some years back had a Super Viking, same as the airplane in the video. He loved the flying qualities of the airplane but indicated that it did tend to have behavior at low speed that was more like that of an airplane of a much higher planform load. His was apparently characterized by abrupt stalls that came with very pronounced pitch-down motion.
 

BBerson

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I think the Viking pilot was flying behind the power as you described or mushing as Wolfgang Langewiesche would say in his book Stick and Rudder. The nose was too high for a normal glide. He appeared to be doing something called "falling leaf" or rocking back and forth in a slow mush with a high descent rate but not quite enough for a clean stall break.
BB
 

Inverted Vantage

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It looked like he kept trying to pull the nose up to gain altitude/arrest the descent, but every time he did he killed what little airspeed he had. He kept yanking it up over and over until finally he lost flying speed and pancaked. Instead of putting the nose down and flaring, he kept yanking it up and went in hard.

That's my opinion, at least.
 

ultralajt

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Yes, maintain the speed to glide well...

But there is a catch!

If somehow during the moments when motor stops to pull the plane, speed dropped. This happens very low at tree-top lewel, so pushing the stick forward to gain speed, will have a height loss as a result (if flying high, this is not a problem...just trade some potential (height) energy to kinetic energy(speed).

But as seen from the video, pilot was not in situation to push nose down as it will defenetely hit the trees (it will lose some height until new flying regime will establish)... so he just stay at high angle off attack and current (low) gliding angle just to cover the last trees and after that, there was defenetely no more vertical space (height) for stall recovery. You know, as you drop the nose, angle of attack drops, lift drops and plane fall down even more until new airspeed is established under this new wing angle of attack. And half of tone of aeroplane dont get extra gliding speed in a moment. It easier with gliders and ultralights than GA planes.

I attach here a sketch, where I present what I am talking about.

Flying path A is what we seen from a video, ad B path is "by the book". But a problem if acting "by the book" is that there could be a possible colision with trees during a stall recovery height loss, even by a fact that glide would be prolonged and angle of hitting the water lower.




Just my opinion on that matter...could be wrong... :nervous:

Regards!

Mitja
 
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rtfm

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Interestingly, the plane (when it first appears on the video) is already very low, and traveling very slowly. Which begs the question of how long prior to this footage had the pilot been struggling to make it over the trees to a safer landing site.

Perhaps he had initiated the correct procedure some time before, and just couldn't eke out the required distance. And so tried to squeeze out a few more feet by keeping the plane on the verge of stalling just long enough to make the relative safety of the water. If this is the case, it would have been better had he initiated this with more altitude, of course. But hindsight is never wrong...

And I notice a distinct change in flight path right at the end. He seems finally to have decided to fly the plane in (too late) and effect a halfway decent landing on the water.

Given that this is an aircraft with a propensity to sudden slow speed stalls, I think he might in fact have done a very skillful job, and simply ran out of altitude.

Duncan
 

Dan Thomas

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Interestingly, the plane (when it first appears on the video) is already very low, and traveling very slowly. Which begs the question of how long prior to this footage had the pilot been struggling to make it over the trees to a safer landing site.

Perhaps he had initiated the correct procedure some time before, and just couldn't eke out the required distance. And so tried to squeeze out a few more feet by keeping the plane on the verge of stalling just long enough to make the relative safety of the water. If this is the case, it would have been better had he initiated this with more altitude, of course. But hindsight is never wrong...

Duncan
That's what I see. He didn't establish the best glide speed earlier and ended up low over the trees. And he managed to keep it level, right on the edge of the stall but with a horrific sink rate at the end.

FWIW, in flight instruction we never refer to "tip stalls." That's a modeler's term that has misleading aspects to it. It implies that the wings will stay level and controllable until the wingtip stalls, which is far from the truth. Most aircraft are designed to have the stall start at the trailing edge at the wing root, and move forward and outward from there. If enough lift is lost the airplane drops its nose as the center of pressure moves aft as the airfoil's stalled area spreads forward, and if there's a yaw involved, or some minor misrigging of the wing that has it at a higher AoA on one side, the loss will be greater on that side than on the other and that wing will drop. The tip may well be still flying, provable by proper response to aileron input, but the wing will drop before the tip ever stalls just because the tip alone isn't enough to carry the weight. Airplanes like the 150 and 172, with their washout and airfoil changes from root to tip, seldom stall the entire wing and therefore make forgiving trainers, but they can also instill a dangerous sense of mastery in a pilot who has learned to fly in one and then buys something less forgiving.

We call it a wing-drop stall, or incipient spin. In Canada the PPL student needs to see incipient and full spins and their recoveries, and the CPL must perform them on the flight test. We spin all the time and carry out all the various types of stall scenarios: departure stalls, climbing turn stalls, accelerated stalls, skidding turn stalls, and the like.

Dan
 
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BBerson

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Without knowing at what altitude the engine quit, I cannot say that the pilot did anything wrong. But it is unlikely that his engine quit at 100 feet. Why would he be flying at 100 feet with passengers?
So I suspect the engine quit at a much higher altitude and the pilot could have done a better job holding enough airspeed for a bit of a flare. But he survived and avoided a spin, that deserves to be recognized.

Captain Sully did a good ditching his airliner. Sully may have had more glider time than this pilot.
BB
 

Dan Thomas

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Captain Sully did a good ditching his airliner. Sully may have had more glider time than this pilot.
BB
And airliners have a much better L/D ratio than light airplanes. Sully would have had extensive training in all phases of flight, including ditchings on the big simulators, I'm sure.

Dan
 

BBerson

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I could be wrong, but I read somewhere that airline pilots do not get training in complete engine loss simulation.
Your right, big airliners glide about 20 to 1. But the sink rate is quite high.
BB
 

rtfm

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Sorry - you lost me... A glide of 20 to 1 (to me) implies 20 units horisontally, 1 vertical. If so, how is the sink rate high? And 20 to 1 for a big airliner seems wrong. What am I missing?

Duncan
 
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