Originally Posted by shy talk
(Post 6896940)
If he'd had a yoke, the others could have more quickly grasped what he was doing.
Surely, no-one can argue with that. The aviation accident record is littered with the smoking craters and floating wreckage of stalled yoke-equipped planes. Planes which crashed with PF pulling back into and through the stall. Surely in those cases, "the others" must have grapsed what PF was doing ? I would argue that yes they did, but it didn't help. They grasped "pulling back" (doing) but they did not grasp "stalling the a/c" (consequence). Or to put it another way, what would you say the Colgan PNF "grasped" about what PF was doing (pulling back) when she took action to pull the flaps up ? Stall ? or "climb" maybe ? [Yes, he might have been thinking "tail stall", if you believe that theory, but only he had seen the tail stall video and the flaps was without his command, so can't be that] Now back to 447, where was it lost ? In the climb (I'm with Lyman on this). Once stalled, in poor conditions and without visual reference, their chances (I think) are already slim. So, did lack of visual control feedback prevent PNF grasping what PF was doing in the climb, thus resulting in the stall ? Nice theory, but no. PNF knew PF was climibing, he also knew PF shouldn't be climbing and told him to descend. More than once. Had PF followed that instruction they'd probably still be alive. The fatal problem is not that PNF didn't get what PF was doing at the critical time, it is that neither of them grasped the consequences of that action, despite all the warnings and instrument indications of stall. Why they failed to grasp that is a very very interesting question, but it has nothing to do with stick, because PNF knew PF was climbing - crystal clear from the transcript. [ I'm excusing the captain at this point - he comes back in when the a/c is already so far beyond tested and simulated flight envelope that systems are going wrong all over the place, and he's fed a history that is well on the misleading side of useless. ] |
I've seen PF's with their seats positioned way back and in reclined positions. Could this be a purely speculative factor as to why a slight aft input would be accidentally place on the side stick when the auto pilot disconnects?
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infrquentflyer789,
not being a pain in the ass, but can you point me to where, in a transcript, the PNF noticed ( & verbally requested a correction of) their unauthorised climb, from the PF. I haven't waded through absolutely everything relating to this accident, but don't remember this ,very specific, request, being identified. |
Originally Posted by captplaystation
(Post 6897220)
infrquentflyer789,
not being a pain in the ass, but can you point me to where, in a transcript, the PNF noticed ( & verbally requested a correction of) their unauthorised climb, from the PF. I haven't waded through absolutely everything relating to this accident, but don't remember this ,very specific, request, being identified. Watch your speed Watch your speed Okay, okay okay I’m going back down Stabilise Yeah Go back down According to the three you’re going up so go back down Okay You’re at Go back down |
Hi,
The fatal problem is not that PNF didn't get what PF was doing at the critical time, it is that neither of them grasped the consequences of that action, despite all the warnings and instrument indications of stall. Why they failed to grasp that is a very very interesting question, but it has nothing to do with stick, because PNF knew PF was climbing - crystal clear from the transcript. It's interesting to add the time of the events 2 h 10 min 06 The flight control law changes from normal to alternate. I have the controls 2 h 10 min 27 2 h 10 min 31 Watch your speed Watch your speed Okay, okay okay I’m going back down Stabilise Yeah Go back down 21 seconds before the first PNF call ... (PNF knew after 21 seconds that they are climbing) They are in the climb from all those 21 seconds ... In this kind of event 21 seconds is a big lap of time ... |
Amen ! but for the DGAC/Airbus to accept the blatantly obvious, it is also (prohibitively) expensive. . . . . so you & I (and anyone who cares to agree with us) are wrong. . . . OK ? |
Am I the only one to find it... well, extraordinary is the only word that comes to mind that a commercial pilot could get into the right hand seat of a international widebody and not have seen St Elmo's fire?
I suppose it speaks volumes on the experience level of some (too many?) of the occupants of the right hand seats of too many commercial jets today. |
When the Captain, with his lack of knowledge of what had gone on before his arrival, arrived on the FD |
Personally I think at that point (return of the captain) they were already going to crash barring some sort of miracle 2 h 11 min 43 The thrust levers are moved from TOGA to MCT. The N1 are stable at around 102 %. Sound of cockpit door opening Er what are you (doing)? What’s happening? I don’t know I don’t know what’s happening Red = altitude 2 h 11 min 45 35,372 The 3 angles of attack are invalid (NCD status). The last valid value of angle of attack 3 is reached at 2 h 11 min 44 and is 41.5°. The stall warning stops. The pitch attitude is 15°. The roll angle is 32° right increasing. The vertical speed is no longer calculated by the IR (Inertial reference) but by the ADR. It is about -10,000 ft/min. End of “Stall, stall” warning + cricket Altitude = 35000 when captain reach FD Miracle needed ? |
I don't fly FBW, but I do like to know where and in which direction the yoke is moving.
If it is creeping slowly backwards, it tells me what the airplane might soon do. If it is held right back for any length of time, I know what the airplane has already done, and will continue to do! I'll leave the argument about the relationship between stick position and stall to another thread. |
I stand corrected, I thought they were lower than that when the Capt. showed up.
That said, you can't expect him to draw the correct conclusion within seconds of arriving on the flight deck, possibly sleepy and finding unexpected mayhem in the cockpit. Still I would say 30 seconds should have been enough for anyone to see what's going on and even at 10K fpm descent that leaves some altitude. |
Originally Posted by jcjeant #773
21 seconds before the first PNF call ... (PNF knew after 21 seconds that they are climbing)
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The miracle lies in expecting the pilot to rotate the airplane from 15 degrees NU to 25 degrees ND, to unstall it from AoA=41.5 degrees.
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The miracle lies in expecting the pilot to rotate the airplane from 15 degrees NU to 25 degrees ND, to unstall it from AoA=41.5 degrees. This is fundamental to stall recovery and should be basic knowledge to any professional pilot. An a/c can stall at any speed or attitude - you could be diving vertically towards the ground but still be stalled. |
That said, you can't expect him to draw the correct conclusion within seconds of arriving on the flight deck, possibly sleepy 10 minutes is the gap time between captain live and come back in the cockpit ... I ask myself the same question of whether he was lying during those 10 minutes .. Sleepy ? |
move the control column/side stick forward until the stall identification ceases. Why would pushing be so difficult? |
That's at AoA=6 degrees. OK, I exaggerated a bit, should have said 20 degrees down. Are you confusing a change of angle of attack with a change in attitude? |
The FPA wo'nt change much until the A/C is unstalled and able to develop g's. Therefore the change in AoA is of the same order as the change in pitch.
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shy talk:
PEI. No. Sure, the problem was with the flight path. But there would have been no problem understanding why the flight path was upwards had the PF been seen to be holding full aft yoke, like his life depended on it. Have you ever made a full nose up input in the cruise? The sidestick disguised what PF was doing from PNF (and anyone else on the FD). It's clearly a big factor in what happened that night. The problem (that a yoke might have made it easier to deal with) is that when the Captain, with his lack of knowledge of what had gone on before his arrival, arrived on the FD, he had less chance of instinively grasping the situation because PFs inputs were far from obvious. A problem is that the Captain had fewer tools to hand as he arrived to sort out what had gone amiss. He had to do this because of THE problem (1) Two pilots in the cockpit didn't sort out that they were bleeding off airspeed, nose up, into a stall. THE problem (2) The aircraft was stalled unintentionally without either pilot in the cockpit seeming to realize that the stall was entered, and then in progress. This takes us back to the much discussed (a few threads back) stall warning issue. My surmise is that both of them had the following idea/thought: "A/S is unreliable, why listen to stall alert?" As I see it, this cognitive matter (if true) is a critical causal factor. Figuring out if that's true, and what to do about it ... nothing to do with yoke nor sidestick. He almost certainly could not see the F/Os' sidestick in that dark cockpit. Some may argue that had he seen what the F/O was doing, he'd be happy for him to continue holding full aft input as they fell. I think not, though. In fact, is there any evidence that the Commander even knew who was flying, never mind what they were doing? Nevertheless the combo of using sidesticks and not having them linked together or even in plain view was a contributory factor in this accident. To argue otherwise is inane. I am sure you are aware that there is a great deal more to knowing your aircraft's performance than control stick/yoke position. Hazelnuts. Getting the nose up there didn't seem to cause him any trouble. Why would pushing be so difficult? |
You can also see that when (during the rapid descent) the pilot changes the position of the SS forwards .. and due to the famous limit of 60 knots .. the stall alarm sounded and immediately he starts again to pull on the SS
Yet when a stall alarm sounded the reflex must be to push the stick forward And everyone who read this forum now know that famous limitation of 60 knots who inhibit the stall alarm It seems that the pilots did not know this limitation Yet it is explained in the documentation Airbus So what read these pilots ? the comic strip Garfield ? Or do they are pilots who think that after a trip from point A to point B .. their work stop there? Not interested to have more knowledge .. to improve professionally ? |
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