Some Inspiration for BoeingBobby

[Evan]

Well, you get enough Red Bull in you and the stupid becomes obligatory....

[Evan]

Łukasz Czepiela, a Polish A320 captain and Red Bull aerobatics pilot, lands a cub on the Burj Al Arab Jumeirah hotel helipad. But, big deal, it had a posh electrical system (and brakes, I assume). And then he takes off again.

My father told me when he began his flight training in the USAF, they taught him how to practically hover under strong headwinds in the cub.

But this is some next level cowboy sh*t. I hope he likes it nice and boring on the A320.

https://www.youtube.com/watch?v=B-brmk1ua1g

[Evan]

I think the moral of this thread is: the second time's the charm....

[Evan]

A Cessna does not have a yaw damper. You use the rudder quite often for turn coordination and to deal with adverse yaw.
Airplanes with a relatively sort wing span make it possible to roll into high-bank angles in wake turbulence where rudder might be needed to recover (not rudder reversals).
An A300 (or any large jet) does not need rudder for turn coordination or adverse yaw compensation, nor does it roll into high-bank angles in wake turbulence.
Large jets need rudder in one direction for crosswind landings, thrust asymmetry, and both directions for ground handling and some ultra-rare circumstances like shaking the gear loose on gravity extension and shaking the hijackers off their feet. That's it for rudder....

[Evan]

That track he shows might have been the intended one (turn to base just seconds after passing abeam the threshold!!) but it can’t be the one flown. The cabin video shows the plane begins the bank to ‘base leg’ while the temple hill is still beneath the window....

[Evan]

Well, then stick to Cessnas please....

[Evan]

This was a roll upset.



That's coming from the people who slide ruled the airplane into being. They are much smarter than any of us (except Gabriel).

Notice the lack of grey area there. Notice that Gabriel has noticed this.

It's come to the point where I have to ask you: are you capable of learning?...

[Evan]

Ok, yes, I agree that this wasn't an A330 and that the A330 is a better, more tolerant system. I agree with you that no rudder was called for here. I acknowledge points 1-4. But I don't agree that this accident likely wouldn't have happened on the A330 because I think he was just getting started and actually amplifying the upset with intentional rudder reversals. I think he was doing this intentionally because he was trained to use rudder in high-bank (exceeding 90deg) wake upset recovery on smaller airplanes in situations where ailerons become ineffective. And I think he just... didn't... get it. Supporting this is the testimony of other pilots who flew with him who remarked that he had an alarming tendency to be very active with the rudder. He used it as a primary flight control. As for the overswings, that is what we can expect on any large airplane from an open system that does not provide the expected feedback in time to inform and mitigate the input force. I think he would have broken...

[Evan]

I hope you are right. As for PIO being obvious, that's the inherent problem in using rudder for roll. The inherent delay of induced roll leaves it as more of an open-loop system, the kind of system that inspires overcontrol in the first place.

But the BEA argued that it might not have even been PIO:



In that scenario, I think you can also break an A330 or a 747. In any case, I think you will agree that it isn't something we want to find out....

[Evan]

Pretty sure you're on the wrong thread. These were wake turbulence roll disturbances from trailing vortices. If you look closely at the A300, you with spot a very large vertical stabilizer that is there to stabilize any yaw disturbances. Could you please tell us how the his use of rudder was possibly very reasonable in the case that we are actually discussing?

That's a rhetorical question. You can't give a reasonable answer because there isn't one. Sorry, there's no grey area to hide in. Black and white as it gets 3WE....

[Evan]

How close minded can a person be 3WE? I just posted the effing FCOM from the big airplane company stating in very BLACK AND WHITE terms that the rudder is not to be used to control roll (for very important reasons)... and furthermore, never to be used in reversals (for very important reasons). Therefore, it is impossible for such inputs to be very reasonable. I'm beginning to think you might have a reasoning disability....

[Evan]

It absolutely has something to do with it. The more sensitive controls exacerbate the situation, but it is not the causative factor to focus on. Again, if the pedal required only the slightest touch and was applied in one direction and then removed, there would be no structural failure. Better yet if the rudder was not touched at all. I also believe this pilot would have broken the A330 or the 747. It just might have required more work.

Anyway, I’m not out to win, I’m just pointing out the vital lesson the investigation teaches about the role and proper use of rudder on large transport category airplanes. It isn’t useful to propose that this lesson is less relevant to another type because the controls are more forgiving. It’s unforgivable either way....

[Evan]

I thought you were referring to the yaw damper logic. On the A300:



I'm not sure if this is true on the A330....

[Evan]

He was downwind and below the 74. The wake travelled laterally with the ambient wind and descended into the path of AA587. Which was by no means little and would have rode it out bravely with a competent pilot at the helm....

[Evan]

I'm really exhausted on this subject. I'll let the investigation speak for me:

Of the 6 pilots who flew the AA A300 simulation, which was recovery from a high-bank upset event (90-114deg roll, which did not occur on the A300, nor would they), 5 found that the best strategy to recover was either large wheel inputs and no rudder or large wheel inputs and a small rudder input.

Again and again, the exhaustive report points out that the use of rudder to control yaw creates sideslip forces that can lead to loss of control and structural failure.

See the FCOM attachment, (Appendix N of the factual report) which pre-dates the accident ----->

...

[Evan]

Understood, but again, the fatal factor here was not in deflecting the rudder to max deflection and centering it from there. No matter the force applied by the pilot, this would not have overstressed the airframe. Rudder travel is limited in either application. The fatal factor was moving the rudder from left max overswing to right max overswing. What reason would any pilot ever have to do this on a large aircraft? This pilot was trying to use the rudder improperly as a flight control to address roll instability, which induces roll responses with a delayed effect that is a perfect recipe for PIO, large rudder inputs to both sides and structural failure. It's not a primary flight control. It's a compensatory flight control.

Input rudder as needed. Remove rudder as needed....

[Evan]

What makes you say that?...

[Evan]

Not an idiot, perhaps, but a pilot trained for wake turbulence upset recovery on a very different DC-9. Different because the smaller wingspan of a DC-9 allows for the possibility of severe wake upset attitudes where both ailerons can be inside the vortex and the only means of addressing roll at such extreme attitudes may be rudder. Even so, not with rapid reversals. When pilots who had previously flown with this pilot observed his very active use of rudder, they later remarked to investigators that it was disturbing to watch. Like you, this pilot failed to understand the role of rudder on large transport category airplanes and this got a lot of people killed. The sensitivity of the rudder pedals is not the fatal factor, it's the rudder reversal behavior that caused the fin to depart. When you use rudder to induce roll, there is a delayed effect. Therefore it becomes very easy to overcontrol and get into an escalating PIO situation. It's a terrible substitute for ailerons. At least one,...

[Evan]

My proclivity is that they shouldn’t mix commercial aviation with general aviation at the same airport. There is an inequity of safety culture and training requirements, not to mention speeds and equipment, that can—and has—led to disaster.

[Evan]

(and some epic crosswinds)

That is the past my friend, before the industry woke up to the wisdom of stabilization criteria....