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AA-191 encountered a strong wind shear on take off from ORD- gaining 70 knots. Because they didn’t push over enough the wing spar folded.
American Airlines flight 191 crashed on takeoff after an engine detached. 3WE will be pleased to know that, while the plane was still controllable and could have successfully returned, the crash was the result of a stall caused, in part, by following procedure (albeit the wrong procedure). The crew had no warning of the impending stall since stickshaker was deactivated as was the slat retraction asymmetry warning. They reacted only to what they did know: an engine had failed. Procedure was to reduce speed to v2, which put them below stall speed for the wing with slats retracted, and thus the wing stalled. Had they pulled up more it would only have stalled sooner. They could only have been saved by lowering pitch and accelerating. But of course, they had no situational awareness whatsoever and no reason to suspect they were anywhere near stall.
American Airlines flight 191 taught the industry some hard lessons. Stickshaker on the F/O side was no longer optional (an option AA was too cheap to pay for). Leading edge design no longer used hydraulic pressure alone to keep slats extended. The loss of a single engine could no longer cause the loss of stall warning or the uncommanded retraction of high-lift devices. And throwing the manual out because Curly and Moe improvised a time-saving routine involving a forklift to change the engine and the pylon as a single unit was forever-after frowned upon (deadly maintenance improvisations continued to occur, however) .
3WE will be pleased to know that, while the plane was still controllable and could have successfully returned, the crash was the result of a stall caused, in part, by following procedure (albeit the wrong procedure).
Evan will be pleased to know that the crew of AA-191 was praised for applying correct procedures at a very high proficiency.
Aero Engineers however, did some arithmetic and said that a basic fundamental of lowering the nose and increasing speed would give improved control authority, and that- as best as they could tell- the plane could have been controlled.
Also, scientific engineering was used to design the plane so that slats could retract independently in the event of a hydraulic line breach and also engineered the thing to have a single slat indication- and no warning for asymmetry.
All of this leads to very tough gray areas.
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
Evan will be pleased to know that the crew of AA-191 was praised for applying correct procedures at a very high proficiency.
I did not know that, because it is not in the final report.
What the final report tells us, essentially, is that the crash was the result of a lack of situational awareness--a scenario in which no pilot can be expected to perform correctly. The report also tells us that during re-enactments in the sim, pilots were able to recover from the stall (after the roll had begun) by lowering the nose to accelerate, and safely return to the runway. The aircraft needed as little as 4kts additional airspeed to recover. But, of course, the real pilots had no indication of stall (not even buffet) nor any logical reason to assume stall at that point. This is one crash in which it is a blessing that the CVR failed.
But what were you and Gabriel referring to? I assume you got the flight number wrong.
Now, regarding AA-191, the report describes how the pilot slowed down (by pulling up) to V2, speed that they had already exceeded, because the manuals said that in case of engine failure on take-off you have to fly at V2. "Cowboy improvisation airmanship" says that if the plane can keep a speed greater than V2 already achieved and it is climbing and ground or obstacle clearance is not of concern, then there is no reason to pull up and slow down to V2, and we all know that faster means greater control authority in general and especially for the ailerons that quickly lose effectiveness at high AoAs.
Pilots followed manuals instead of cowboy improvisation, and manuals were subsequently improved accordingly to reflect the cowboy improvisation technique.
It is worth mentioning that while the airplane would have been controllable had the pilot not slowed down, the other 2 hydro systems were also leaking slightly, nobody knows (and I personally doubt) if they could have kept control long enough to complete a successful QRF
--- Judge what is said by the merits of what is said, not by the credentials of who said it. ---
--- Defend what you say with arguments, not by imposing your credentials ---
Now, regarding AA-191, the report describes how the pilot slowed down (by pulling up) to V2, speed that they had already exceeded, because the manuals said that in case of engine failure on take-off you have to fly at V2. "Cowboy improvisation airmanship" says that if the plane can keep a speed greater than V2 already achieved and it is climbing and ground or obstacle clearance is not of concern, then there is no reason to pull up and slow down to V2, and we all know that faster means greater control authority in general and especially for the ailerons that quickly lose effectiveness at high AoAs.
Pilots followed manuals instead of cowboy improvisation, and manuals were subsequently improved accordingly to reflect the cowboy improvisation technique.
This is generally how procedures are established. Engineering + experience + modification. But the problem wasn't the procedure here, it was a lack of situational awareness and hence, the wrong procedure. In fact, there was no correct procedure. Cowboy airmanship would have saved them but this is a very rare instance of expired cheese lining up in a very rare way.
The DC-10 manual includes the advice:
The emergency procedures in this section are presented as the best way to handle these specific situations. They represent the safest, most practical manner of coping with emergencies, based on the judgment of the most experienced pilots and FE's, the FAA approved procedures, and the best available information.If an emergency arises for which these procedures do not apply, the crew's best judgment should prevail.
As far as the crew knew, they had only lost an engine and were nowhere near stall.
It is worth mentioning that while the airplane would have been controllable had the pilot not slowed down, the other 2 hydro systems were also leaking slightly, nobody knows (and I personally doubt) if they could have kept control long enough to complete a successful QRF
The report states that the other systems were operating until the end, which was very shortly after the lines were damaged. I wonder if that was considered in the sim re-creations.
The severing of the hydraulic lines in the leading edge of the left wing could have resulted in the eventual loss of No. 3 hydraulic system because of fluid depletion. However, even at the most rapid rate of leakuge possible, the system would have operated throughout the flight.
So “we” want them to use judgement and not proficient, immediate execution of the correct, specific memory procedures for the indications- ‘exactly’ as practiced in simulation?
Don’t mention to Gabriel how a measured nose down input would have affected net control authority of a couple of 737’s (Note: a different type)
Should “we” want pilots to (with judgement) to ‘first’ try measured nose down inputs for the sake of lift and or speed and or control and NOT give priority to nailing V-2, getting sone generally useful altitude and then assessing the situation?
Or does that then cause the other rare occasions when the other 191 to nosed over a bit much, or 727 guys do not do last ditch pull ups as the fence approaches?
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
So “we” want them to use judgement and not proficient, immediate execution of the correct, specific memory procedures for the indications- ‘exactly’ as practiced in simulation?
Don’t mention to Gabriel how a measured nose down input would have affected net control authority of a couple of 737’s (Note: a different type)
Should “we” want pilots to (with judgement) to ‘first’ try measured nose down inputs for the sake of lift and or speed and or control and NOT give priority to nailing V-2, getting sone generally useful altitude and then assessing the situation?
Or does that then cause the other rare occasions when the other 191 to nosed over a bit much, or 727 guys do not do last ditch pull ups as the fence approaches?
The crew of AA-191 were not doing stall avoidance. They had no stall warning and no reason to think stall was imminent. I don't think you're getting that (although I made this rather clear).
The language in the manual begins with "If an emergency arises for which these procedures do not apply..." There is no procedure for losing the engine along with the pylon, the electrical bus tie and the hydraulic redundancies for the right wing slats. So this is an emergency where "the crew's best judgment" is the only resource. However, again, they didn't know this had occurred and so they followed the procedure that existed for engine failure alone. If the emergency had been the emergency they thought it was, slowing down to v2 would have resulted in a safe return.
"The crew's best judgment" begins with assessing the situation, so it is always involved. If situational awareness is correct, the procedures are the best, first action to stabilize the upset. If the situational awareness is flawed, "the crew's best judgment" will be flawed as well. Do you get that?
Cowboy airmanship alone, on the other hand, is not always the best, first action because, unlike procedures that are proven and consistent, cowboy airmanship varies with the judgment and proficiency of the cowboy airman, which in turn varies with the stress and overload of the situation.
Case in point: AF-447: The PF was initially reacting to loss of autoflight, not loss of airspeeds. That was his first situational awareness when he pulled up. Had his first action been to follow the practiced, memorized procedure for loss of autoflight, he would have maintained attitude and switched off the FD's (which may have been telling him to climb). It's quite possible that he may have pulled up because he was following the FD's at that moment. I'm not saying that is what happened, but it illustrates the importance of memorized procedure as a first action following first situational awareness, to defend against things that beget spontaneous human error.
But I know you will never acknowledge that.
The fact is, the only way to prevent another accident like AA-191 is to prevent the sequence of events that led up to it and to provide better redundancies against it. There is no piloting solution.
My perception is that Evan’s answer is “not enough”.
AA-191 always bugged me as the pilots nailed the procedure but supposedly only needed nose over a tad.
The question of should they have or could they have is not simple.
You have not seen my hair- the gals at great clips generally do a good job.
Would you like to contribute your oft-cited great knowledge or can you only handle hair jokes.
I was just commenting on your total ignorance on what and how many "memory" items there are on each type of aircraft. (5 on the 747/400 and they are no longer memory items but immediate recall) And the Pope already sent me an email about how good your hair looks! LOL
Knowing only what they knew, what reason did they have to 'nose over a tad'? None!
None at all whatsoever?
I count about 90 reasons...(Gabriel might count 1.58 reasons).
It's called "The plane banking left when I've got the wheel turned right". That was a pretty significant cockpit indication.
I will tell you that this works during a secondary stall in a 172.
Gabriel tells me that it might have worked on a couple of 737's with rudder hard-overs.
You told this thread it might have worked on AA-191.
I know there is zero validity to compare procedures across types, but...
I do not pass judgement on the pilots for their actions that day. Numerous cockpit indications told them they were doing the right thing and there was not a whole hell of a lot of time to deal with stuff even if they had the lacking left wing stall warning AND the left wing slats up warning...
I did always find it sad that they so proficiently did the V-2 thing when You and Gabriel say they could have nosed over a tad (Just like the poorly trained Gabe and I did).
I also, (stupidly) keep hope that your rather black and white view of adherence to type-specific procedure (while bashing really basic stuff that works across aircraft (like 172's and 737's and DC-10s)) might give way more than it has.
In a perfect world- the DC-10 guy would have tried a little nose over as the 90-degrees of bank ticked away AND said to hell with V-2.
Would I have done that, Gabriel, Bobby, You...I have no idea- they were in a very shitty situation as you point out.
Bobby, thanks for the info on memory checklists- I do think safety engineers and training pilots work very hard to have very good training programs. Do you find any sadness that 'mathematically' AA-191 was said to be flyable?
Les règles de l'aviation de base découragent de longues périodes de dur tirer vers le haut.
I do not pass judgement on the pilots for their actions that day.
AA-191 was not pilot error. By the time the uncommanded roll occurred the stall was unrecoverable by very confused human pilots with no SA whatsoever. The SIM pilots knew what was happening. The real pilots only knew they had healthy airspeed and attitude but then sudden uncommanded roll due to... [crunch]
To help you understand the extreme set of circumstances that led to this crash, I knocked up a flowchart. It's in black and white AND red:
Note that in the crew warning and crew action rows, the first column (actual crew awareness & actions / non-fatal) and the fifth column (actual crew awareness & actions / fatal) are exactly the same but with very different outcomes.
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