AF471 - Nov 16th 2011 - Final Report

[PEI_3721]

flyhardmo, thanks, some interesting points.
The THS operation in manual flight is understood, but how does the AP involve the THS; AP command of autotrim would be logical to relieve the control system effort as discussed above.

It is assumed that the THS movement was due to the AP’s response to the change in pitching moment – opposing the overriding control input and/or the thrust increase, with possible further input due to configuration change. However, with FBW why would a stick input be used to control the aircraft (to oppose the AP) when the AP is engaged, cf Airbus.
If the override stick input has no control with AP engaged, then the THS change was probably due to thrust / configuration change, which leaves the potential for a residual out-of-trim condition when the AP disengages (disparity between stick position and control surface position) until “the control system transitions the control surface commands from those of the autopilot to those of the flight crew”, i.e. a period of readjustment with the pilot not totally in control, which is probably not significant … … unless there is a large change in pitching moment – woops.

Re the disconnect force; the description suggests that there is a ‘hole’ in the logic. If the crew override the AP following a down grade from a high integrity approach mode (cat 3), in circumstances where the AP does not disengage, then the overpower-disconnect logic changes / is non-existent.
Alternatively, (via Chris) do opposing stick inputs invalidate the overpower-disconnect logic; or does the disconnect description only relate to a jammed (blocked) stick, which may not apply with AP engaged.
What control forces (and movement) are fed back to the stick with AP engaged?

[flyhardmo]

That sounds straight out of a sales brochure! My question was: does it have to trim forward during a normal go-around, and - if so - roughly how much? In other words, did the fact that it had trimmed 1.65 deg forward before the AP disconnected subsequently make the pilots' manual rotation to a go-around pitch more difficult, or would they have needed to trim forward anyway?

There is no trim wheel in the 777 so unless you are looking at the stab trim band you don't have an instantaneous idea how far or fast the trim is working. Like I said, in manual flight you just rotate to set a pitch attitude for GA and the only time you feel that you have to trim is when you increase the SPD. In the drivers seat I have no idea what the ST is doing but I assume it's counteracting the pitching moments with FWD trim. No sales pitch, just the way it works which is most likely why (just having an educated guess) it trimmed 1.65deg forward because the SPD was increasing. ( going down the GP with full thrust).

What control forces (and movement) are fed back to the stick with AP engaged?

The control yolk moves with the A/P engaged as it would in manual flight as do the thrust levers. With your hands on the throttles and yolk you know exactly what the A/P is doing.

I'm still not sure why everyone is making a big deal about the position of the stab trim. I don't think it's really a factor. Disconnecting the A/P by overriding the stick force is not a normal practice on the 777 operation and seemed like it was done in desperation. The PF was fighting an aircraft trying to maintain the GP on autopilot rather than press TOGA or use the A/P disconnect switch.

[Trackdiamond]

There seems to be a spectacle of noise o this thread on "who-done-what -it is".
How about examining the Human Factors that led to the cockup in Automation mismanagement in the firstplace?
This was a perfectly functional aircraft.
The crew had plenty of total experience and hours on type.

What were the crew rosters like till the material incident date?
Were there any phisiogical causal factors that might have undermined the Captain who was PF?
Were there any stressful events enroute (factoring in times of operation and circadian dysrythmia)..?The nominated PM did not appear particularly alert..hence the vocal takeover by the relief FO!At least some one was awake!
Why,however, didn't the relief co-pilot annunciate more succinctly as is the required standard for LVO operations?Why didn't the PM take over as a matter of SOP after observing such a dangerous excursion..and in any case the PMs would have been more heads down and on the instruments and in theory better awareness of flight tragectory whilst the PF(Capt) would have been busy checking external visual cues to make a decision..I.e. the monitored approach model.
Both PF and Pm apparently were not paying atention to the FMA!
I believe this incident centres overwhelmingly on Human Factors.Will check the actual report to see how focal that issue was treated in the final analysis.

[porterhouse]

Boeing AP disconnect alarms are softer in comparison

My God it is quite loud and very characteristic in tone. If someone misses this sound (or its accompanying flashing red light) it means their mind must be in a la-la land.

[jcjeant]

BEA Report page 1

Le CVR, préservé par l’équipage, a été effacé par erreur avant qu’il ait pu être exploité par le BEA.

CVR, preserved by the crew, was deleted by mistake before he could be analysed by the BEA

This is not the first time this has happened with Air France
So if you want to make something disappear ... give it to Air France .. they are like magicians

[Chris Scott]

Quote from flyhardmo:
"In the drivers seat I have no idea what the ST is doing but I assume it's counteracting the pitching moments with FWD trim."

Are you saying that the B777 has no EICAS or other indication of current stab-trim (horizontal stabiliser) position?

[ATC Watcher]

jcjeant : It is true thance since Habsheim the relations between AF and CVRs are quite complicated

On the other hand when one sees that every complete CVR in France is ending in " le Parisien" or "Le Figaro" suggesting totally innapropriate crew behaviour ( Quiberon/Proteus, Pau and more recently AF447, to name only 3 ) the temptation to make a " by mistake " might be high..

[flyhardmo]

Are you saying that the B777 has no EICAS or other indication of current stab-trim (horizontal stabiliser) position?

You can pull it up on the FCTL page but it's not something you normally look at in normal ops. The other indication is on either side of the centre pedestal.

From the FCOM
When pilot trim inputs are made, the PFCs automatically move the elevators to achieve the trim change, then move the stabilizer to streamline the elevator. Stabilizer motion may also automatically occur to streamline the stabilizer and elevator for thrust and configuration changes.

All this is very instantaneous and as a driver you don't feel the A/C trimming through the control wheel.

Porterhouse

My God it is quite loud and very characteristic in tone. If someone misses this sound (or its accompanying flashing red light) it means their mind must be in a la-la land.

Exactly it makes a hell of a sound and even the A/T disconnect gives an audible warning with a caution light and EICAS msg.
This was a classic case of mode (FMA) awareness. There is a big 'A/P' just above the PFD ( primary flight display). It's not very subtle

[Trackdiamond]

Pitch trim awareness

Airplanes that have no manual trim wheels or lack tactile feel to trim activity usually have trim indications in the normal field of vision of pilots or incorporated in the normal display page on EICAS/ECAM or centre miscellaneous advisory panel.Additionally some planes flash a pitch mistrim message on the FMA additional to a trim aural whooler if operated more than 1 second manually..and activation of normal pitch trim causes AP disconnect.
That said..Pilots are supposed to have well trained and observant eyes and display sensitivity and competency in instrument scan,interpretation,and flight control.The FMA is there to make life easier..not lazier for us..let's use it like our eyes and ears! And..when the FMA screams at us an alarm and we miss it through panic stricken motions...and we end up causing an upset both in the cabin and in the office..or after the final analysis give reasons for the crash detectives to promounce "pilot error"..and tabloids and hollywood to portray us for less than what we are supposed to be...

[wiggy]

You can pull it up on the FCTL page but it's not something you normally look at in normal ops. The other indication is on either side of the centre pedestal.

Agreed. The analogue (tape) trim indication sits on the centre console out of any normal scan. You'll also get an EICAS warning for any uncommanded trimming.

The 777 can certainly do some interesting things if you foul up a "high level" go around , but regardless of FMA scans, warnings and HST trimming all that matters at low alt is that if you hit TOGA the thing powers up and pitches up towards 15 degrees..... At least the "heavy" pilot was on the ball.

[totempole]

What I write is gonna get a whole load of barking from the PC crappies!

The777 is designed to be flown by 2 pilots. It should never need 3 pilots ( except during training with a trainee who is yet to be qualified as fleet/type functional, or of course a line check, audit check, etc ).
Introducing a third pilot ( no matter what the PC crappies aver, recommend or insist ) introduce an " unknown " in the form of " psychological pressure ", " snooping with later bar room trashing ", " nosey peeking " etc. Sometimes the third pilot input has a "STUN " effect or " STUMP " effect, or even an" IRRITANT " effect NO MATTER WHAT THE ANAL RETENTIVE CRM advocates aver!

This all affect the " psychological " state in a modern 2 man cockpit. You can all justify all you want, but the non-requisite 3rd man is a silent, stealth liability...the world of good it did in the OZ214, the best it could have done is to lull everybody into a false sense of security.

Had the AF471 skipper ignore the " stun " effect of the 3rd pilot's call and continued, it would have been a non event with a LAND 2 fail passive autoland. With runway sighted as noted, he could have even disconnected the AP and landed manually. The " STUN/STUMP " effect was largely responsible for the brain fart that cause him to activate the AT disconnect button instead of the TOGA switches. During a deeply mentally focussed Cat 3 approach, the PF's faculties are HARDWIRED to get input and callouts from the RIGHT SEAT PILOT, not a voice from the back! The Cat 3 training is such! Any voice from the back can and will cause a STUN/STUMP effect leading to all sorts of brain farts.

Now I am sure there will be dissenters and anal CRM crappies jumping onto this; believe me, YOU ARE ALL STUMPED! And you will remain brain stumped as long as you believe the crap of the so called " safety benefits of a third pilot " in a COCKPIT/TRAINING DESIGNED FOR 2 PILOTS!!!

[olasek]

I can't speak for Boeing...so let's hear it for those that have flown both

If you can't speak for Boeing why you were putting forth a proposition that Boeing's audible signal is perhaps too "soft".
Also it is not a competition who's alarm is louder . It must be sufficient, which it is. Plus you completely disregarded presence of the visual warning as well.
To date there was no accident report which would suggest that Boeing's AP disconnect alarm is insufficient.

[Kilda Ste Hilda]

Totempole has a point there...I always never get to my A game whenever we have someone nosing around in the jumpseat no matter how quiet, smart or competent she/he is. They are a distraction however well intended the policy of having a third guy in the cockpit. Somehow they don't fit into a 2 person cockpit concept.

I have briefly flown in a 3 person cockpit in a A300 B4; the 3 person crew concept in that aircraft was superb because the training and procedures were developed for a very effective 3 crew management. However in a cockpit designed for 2 pilot operation, the third person is a potential stealthy liability however well intentioned her/his presence. Check flights are a different kettle of fish...any argument bringing that in is just being argumentative.

[Hogg]

Yes very valid and exact point Totempole. Even on 767 "jumpers" can confuse things with a 2 man/woman! crew.
When I flew 3 man (B727) it was different but my FEs had great eyesight! twas fab having a 3rd set of eyes being a crewmember not one thats out to score points as it happens nowadays. Always the small ones! I keep em out like my colleagues do now.

[exeng]

I agree with Kilda here.

The three crew concept with a fully integrated Flight Engineer/Third Pilot was the best operation I was ever involved with - it just worked well in my opinion..

When another Pilot is on the jumpseat/observing, or whatever, they do not seem to 'add' to the operation as they are not 'part' of the operation.

The 'third crewmember (F/E or Pilot) were part of the operation and therefore took some responsibility for what happened. An observer as such adds nothing and may be quite destractive.

[wiggy]

Working for an outfit who are very keen that the relief pilot is "involved" I'd have to say that I am in some agreement with the above, however looking back at the OP's bullet point 3

Relief pilot calls out ''Alarm'' the PNF calls out ''go-around'', the PF responds by applying full power to initiate the go-around, which disconnected the Auto-Throttle.

I'd suggest the die was cast once the PNF had made their call...

[glofish]

I very much agree with totempole.

Flying for an outfit who displays its infinite wisdom by not providing any seat possibility for augmenting crew but the two jump seats, i could give ample testimony of "stunned" or "stumped" operations induced by moronic utterings from an overcrowded cockpit.

I am all for having more hands on deck if the skipper so feels the need. My former employer handled it correctly by stating that it is his call to have the supernumerary in or out of his cockpit, but this implies a proper seat for the supernumerary (which by the way is the only civilised and respectful way for airlines).

As has been mentioned, the training in a two man cockpit layout is exactly that: Two men/women. OZ heroic handling or not (I actually don't think it increased safety, only flight time .....)
with the ever increasing fatigue factor on such cockpits, we should stick to what we learned and trained. Every deviation is a disturbance factor when tired and stressed.

No excuse though for this AF crew, only an explanation for the hick-up.

[falconeasydriver]

The NO DH was removed about three years ago - why, I have no idea.

As was explained to me, in simple terms by someone involved in the decision…"to pass liability to the operator/PIC"

[pax2908]

glofish, please clarify, are you suggesting that the presence of the relief pilot in the observer seat, during the final phase of this particular flight, might have been a distraction rather than an increase in safety?

[misd-agin]

Which manufacturer's A/P disconnect alert is louder? Both are loud. So one is louder and the other is louder. No one can miss either alert.