infrequentflyer789

Not in one sense, but I would argue that it isn't understanding what he was doing (pulling back) that is important, but understanding the consequences of that action on the a/c.

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. ]

clark y

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?

captplaystation

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.

infrequentflyer789

Transcript is on page 90 third interim report, english translation. For the first call, I am sort of presuming the first "speed" is VS since airspeed is known unavailable and the response is "going back down"... PNF in blue.

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

jcjeant

Hi,

Critical time ?
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 ...

Gretchenfrage

Unfortunately that is about the only sure consequence of all investigations about AF447.

Andu

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.

JCviggen

Personally I think at that point (return of the captain) they were already going to crash barring some sort of miracle. The damage had been done. I do believe had he been on the flight deck all along we probably wouldn't be having this topic right now.

jcjeant

Blue = captain voice
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 ?

clivewatson

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.

JCviggen

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.

BOAC

- even more concerning to me is that for the WHOLE of the time, as far as the transcript we have is concerned, NOTHING was said about the change in altitude to a level above the max performance level and above the level they had just agreed they could not climb to. It was the stupefying lack of apparent positive action by PNF that in my book carries a large part of blame for the human side of the crash. You only have to sit and count 21 seconds and think of the nose-high, VS high in front of him....................not a word.

HazelNuts39

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.

fireflybob

Not really. Once you have identified the stall move the control column/side stick forward until the stall identification ceases. This might mean you end up on the forward stop waiting for the a/c to recover.

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.

jcjeant

Again .. checking the time of events is interesting ....
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 ?

HazelNuts39

That's at AoA=6 degrees. OK, I exaggerated a bit, should have said 20 degrees down.

When you're going down at a 'crazy speed'?

fireflybob

But why would the pitch have to reach 20 degrees down?

Are you confusing a change of angle of attack with a change in attitude?

HazelNuts39

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.

Lonewolf_50

shy talk:
Respectfully disagree, and find Infrequentflyer789's comments more apt.
Respectfully disagree.

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.
Agree. But could he see the flight instruments, attitude, altitude, VSI, etcetera? That is where his clues of aircraft performance would be, in a Night / IMC flight.
No, probably not.
Yes, he was giving directions at one point to the flying pilot regarding rudder input, among other things, apparently to help him with his roll control.
I can see it as a possible factor, but in terms of rank ordering, it is well behind the problem of two pilots misunderstanding their aircraft's condition for an extended period of time.
Respectfully, no.

I am sure you are aware that there is a great deal more to knowing your aircraft's performance than control stick/yoke position.
Concur. All that is needed is first realizing "We are stalled," after which control inputs would most likely follow.

jcjeant

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 ?