Air France B777 control issues landing CDG
From the examples above:-
Weak auto thrust design, the system could go to sleep; the designer was surprised.
Weak FD switching logic, mandated use of FD for takeoff; the operator was surprised.
Multiple probe icing beyond the conditions assumed by regulation; the regulator was surprised
Weak auto thrust design, the system could go to sleep; the designer was surprised.
Weak FD switching logic, mandated use of FD for takeoff; the operator was surprised.
Multiple probe icing beyond the conditions assumed by regulation; the regulator was surprised
- No attempt to monitor the airspeed during the approach into SFO
- Blindly following the FD during take-off without looking out of the window (or again, monitoring their airspeed!)
- Continuing to maintain a pitch-up input despite the obvious clues!
The adverse human view continues, ‘aircrew’, … ‘error’ - a definition after the fact.
Similarly human activities, ‘monitor’, ‘blindly following’, ‘continuing to maintain’, describe what is assumed to have occurred, but for which we have insufficient knowledge about the crews were thinking, nor their reasoning of the choice of activity / inactivity.
The important question is if it is reasonable to expect crews to manage these situations, considering the nature or rarity of the anomaly, the operational pressures, and crew’s training and experience.
40 yrs ago safety was defined by outcome, body count. Nowadays, still based on outcome, much safer, but we fret over mistaken button pushes, the finesse of flight control and judgement calls, in very safe but vastly more complicated aircraft flown in complex situations.
This incident had a safe outcome; how was that accomplished, compare that activity with the vast number of normal operations. Then and only then consider the specific activities which we judge adverse, what is assumed, taken for granted.
The investigation into this event could help with these questions, but even so, our biased selves with hindsight will conclude what ever we wish; what we choose to learn.
Similarly human activities, ‘monitor’, ‘blindly following’, ‘continuing to maintain’, describe what is assumed to have occurred, but for which we have insufficient knowledge about the crews were thinking, nor their reasoning of the choice of activity / inactivity.
The important question is if it is reasonable to expect crews to manage these situations, considering the nature or rarity of the anomaly, the operational pressures, and crew’s training and experience.
40 yrs ago safety was defined by outcome, body count. Nowadays, still based on outcome, much safer, but we fret over mistaken button pushes, the finesse of flight control and judgement calls, in very safe but vastly more complicated aircraft flown in complex situations.
This incident had a safe outcome; how was that accomplished, compare that activity with the vast number of normal operations. Then and only then consider the specific activities which we judge adverse, what is assumed, taken for granted.
The investigation into this event could help with these questions, but even so, our biased selves with hindsight will conclude what ever we wish; what we choose to learn.
So if I am reading this right, the copilot was surprised by his actions having the exact consequences you'd expect, given this collection of input/output data? Eg. mostly left roll input, airplane banks left.
Or did he maybe expect higher roll rate from the aircraft for his inputs? I know this is just a preliminary report/investigation update, but seems like there was not much wrong with the aircraft.
About the fact that they did not notice their conflicting inputs... I do not fly the type, so excuse my lack of knowledge on the exact flight control config on the 777. But is it not supposed to be one of the upsides of Boeings FBW philosophy, to keep the yokes still moving in sync and provide feedback?
Or did he maybe expect higher roll rate from the aircraft for his inputs? I know this is just a preliminary report/investigation update, but seems like there was not much wrong with the aircraft.
About the fact that they did not notice their conflicting inputs... I do not fly the type, so excuse my lack of knowledge on the exact flight control config on the 777. But is it not supposed to be one of the upsides of Boeings FBW philosophy, to keep the yokes still moving in sync and provide feedback?
Join Date: Aug 1998
Location: the ridge where the west commences
Posts: 770
Likes: 0
Received 0 Likes
on
0 Posts
So....nothing wrong with the airplane other than that the two people sitting farthest forward were not competent and disciplined pilots.
Quelle surprise.
Quelle surprise.
About the fact that they did not notice their conflicting inputs... I do not fly the type, so excuse my lack of knowledge on the exact flight control config on the 777. But is it not supposed to be one of the upsides of Boeings FBW philosophy, to keep the yokes still moving in sync and provide feedback?
There is a 'breakout' feature that can disconnect the two should one get jammed, but it takes considerable force to trigger that 'breakout' and it certainly doesn't look like it came into play in this incident.
Join Date: Mar 1999
Location: N/A
Posts: 64
Likes: 0
Received 0 Likes
on
0 Posts
It seems like both pilots made control inputs simultaneously but there doesn’t sound like a break out of the control columns happened; that requires a lot of force.
Why was the FO confused about the bank? He was hand flying in cloud. Did he become disorientated and/or have “the leans”?
Why was the FO confused about the bank? He was hand flying in cloud. Did he become disorientated and/or have “the leans”?
Only half a speed-brake
The BEA press release clearly spells the flight column channels had been temporarily de-synchronized due to opposing forces on the yoke. 
Also, note "8" explains what that means and the 50 lbs force required. Parlez vous Twitter?
How that works or manifests IRL would be great to hear if someone has the knowledge or experience to share.
Also, note "8" explains what that means and the 50 lbs force required. Parlez vous Twitter?How that works or manifests IRL would be great to hear if someone has the knowledge or experience to share.
Yes, the control wheels are physically interconnected so that whatever one wheel does, the other does.
There is a 'breakout' feature that can disconnect the two should one get jammed, but it takes considerable force to trigger that 'breakout' and it certainly doesn't look like it came into play in this incident.
There is a 'breakout' feature that can disconnect the two should one get jammed, but it takes considerable force to trigger that 'breakout' and it certainly doesn't look like it came into play in this incident.
I think this investigation and its results will be pretty interesting reading, though possibly not very flattering for the pilots...
Join Date: Mar 2016
Location: UK
Posts: 68
Likes: 0
Received 0 Likes
on
0 Posts
Ignoring the initial confusion and left roll by the PF. Seems like the pilots conception of the aircraft not responding to commands as expected could be due to them fighting each other without realising it and believing they are fighting the aircraft? They then apply this mental model retroactively to the initial event?
If they activated the breakout (surprising - the normal loads on the 777 control wheels are pretty light as long as you're not doing something stupid like pulling into a stall - to have to apply greater than 50 lbs. on the wheel should have been a dead giveaway that the pilots were working against each other), I'm reasonably sure it takes a maintenance action to reconnect them (I'm thinking it's a frangible link but I'm not sure about that). So that would explain the aircraft being grounded for a few days after the event.
The force required to override either breakout mechanism is 50 lb.
Last edited by BuzzBox; 28th Apr 2022 at 12:14. Reason: Updated with details of the control column and control wheel breakout mechanisms.
Pegase Driver
Join Date: May 1997
Location: Europe
Age: 74
Posts: 3,686
Likes: 0
Received 0 Likes
on
0 Posts
, Indeed not a good day for them again. The BEA does not make any remark on the rest / fatigue status of the pilots which is one of the main rumors around CDG . But that might come with the full report, although, based on their previous publications, I am not sure the BEA will go too deeply into it..
Good one , Indeed not a good day for them again. The BEA does not make any remark on the rest / fatigue status of the pilots which is one of the main rumors around CDG . But that might come with the full report, although, based on their previous publications, I am not sure the BEA will go too deeply into it..
, Indeed not a good day for them again. The BEA does not make any remark on the rest / fatigue status of the pilots which is one of the main rumors around CDG . But that might come with the full report, although, based on their previous publications, I am not sure the BEA will go too deeply into it..Only half a speed-brake
The idea that on a Boeing you can't feel with your steering what the other person is doing or overpower him is a novelty in many circles, mine included.
Join Date: Jan 2015
Location: Centre of Universe
Posts: 371
Likes: 0
Received 0 Likes
on
0 Posts
So recency is an issue and ATC watcher is saying fatigue played a hand. If its recency then its sleepiness (the need for sleep) rather than fatigue. There is a subtle difference ATC Watcher