Posts about: "Action slip" [Posts: 110 Pages: 6]

Originally Posted by remi

I think, for now, "brain fart" or "extremely inappropriate reaction to perceived anomaly" makes more sense for now.

Originally Posted by Musician

What is an action slip?

There's a possible scenario we're discussing here that fits all of the available evidence. It proposes that one of the pilots operated the switches in an unconscious action called an "action slip". This is a rote action that we do without conscious thought when we're distracted: we mean to do something, and then we get our signals crossed and do something else. To learn more, search for "action slip" or "cerebellum" on this thread; I hope paulross adds the keyword to the next build of his excellent index at https://paulross.github.io/pprune-th...171/index.html .

How would this scenario play out?

We don't have enough evidence to pin down the exact sequence, so there are some assumptions here that I hope you find plausible. (And obviously it's not the only scenario that fits the evidence.) We especially do not know who did what and why, so that is all guesswork on my part. The times are taken from the preliminary report. The report places the verbal exchange among the pilots where I put it.

\x97\x97\x97

8:08:39 The 787 becomes airborne. The F/O is pilot flying (PF), with both hands on the yoke. The Captain is PNF (not flying).

8:08:42 The PNF unconsciously flicks both fuel switches to CUT OFF, one after the other. This is a rote action performed after each flight, or as training captain in the simulator.
The action cuts power to the engines; they stop delivering thrust almost immediately, and the turbines start slowing down.
The 787 systems disconnect the electrical generators in advance of them failing. The right side (Captain's side) of the cockpit loses power to most instruments. With all 4 generators offline, the RAT deploys to provide emergency power.

The PF feels the cessation of thrust. He looks at the display to see an ENGINES SHUT OFF message. He assumes the PNF shut them off, and asks him why he shut them off. This is the lowest "probe" level on the PACE assertiveness scale; see e.g. https://psychsafety.com/pace-graded-assertiveness/ or search for "probe alert" on pprune if you wish to know more. The highest level of assertiveness, E for "emergency", would have the F/O put the switches back himself immediately, but that would have required a high degree of confidence in the face of the older Captain that may have been difficult to achieve.

Since the action was unconscious, the PNF replies that he did not do that.

8:08:47 The RAT starts delivering hydraulic power, the engines decelerate past idle.

The PNF realizes that engine power is in fact cut. Eventually he checks the switches he thinks he did not touch, sees the engine 1 switch first and flips it back to RUN at 8:08:52. He then thinks to check the second switch and flips it up at 8:08:56.

The accident sequence ensues.

There's really not much the PNF can do at this point. At 8:09:05, he transmits a MAYDAY.

\x97\x97\x97

Obviously there are variations to this, for example it could have been the PF who put the fuel switches back. (In the above scenario, the PF is focused on flying\x97aviate!\x97and never turns his head to see the switches.) My goal was simply to set out a possible sequence, to see whether it feels plausible. Remember, as you see other scenarios put forth, that any issues a person could wrestle with would also be distracting. While both pilots would be very focused during the takeoff run, the moment the aircraft lifted off, the PNF could well have mentally relaxed a little, opening an opportunity for the action slip.

Thoughts?

Originally Posted by Musician

What is an action slip?

There's a possible scenario we're discussing here that fits all of the available evidence. It proposes that one of the pilots operated the switches in an unconscious action called an "action slip". This is a rote action that we do without conscious thought when we're distracted: we mean to do something, and then we get our signals crossed and do something else. To learn more, search for "action slip" or "cerebellum" on this thread; I hope paulross adds the keyword to the next build of his excellent index at https://paulross.github.io/pprune-th...171/index.html .

How would this scenario play out?

We don't have enough evidence to pin down the exact sequence, so there are some assumptions here that I hope you find plausible. (And obviously it's not the only scenario that fits the evidence.) We especially do not know who did what and why, so that is all guesswork on my part. The times are taken from the preliminary report. The report places the verbal exchange among the pilots where I put it.

———

8:08:39 The 787 becomes airborne. The F/O is pilot flying (PF), with both hands on the yoke. The Captain is PNF (not flying).

8:08:42 The PNF unconsciously flicks both fuel switches to CUT OFF, one after the other. This is a rote action performed after each flight, or as training captain in the simulator.
The action cuts power to the engines; they stop delivering thrust almost immediately, and the turbines start slowing down.
The 787 systems disconnect the electrical generators in advance of them failing. The right side (Captain's side) of the cockpit loses power to most instruments. With all 4 generators offline, the RAT deploys to provide emergency power.

The PF feels the cessation of thrust. He looks at the display to see an ENGINES SHUT OFF message. He assumes the PNF shut them off, and asks him why he shut them off. This is the lowest "probe" level on the PACE assertiveness scale; see e.g. https://psychsafety.com/pace-graded-assertiveness/ or search for "probe alert" on pprune if you wish to know more. The highest level of assertiveness, E for "emergency", would have the F/O put the switches back himself immediately, but that would have required a high degree of confidence in the face of the older Captain that may have been difficult to achieve.

Since the action was unconscious, the PNF replies that he did not do that.

8:08:47 The RAT starts delivering hydraulic power, the engines decelerate past idle.

The PNF realizes that engine power is in fact cut. Eventually he checks the switches he thinks he did not touch, sees the engine 1 switch first and flips it back to RUN at 8:08:52. He then thinks to check the second switch and flips it up at 8:08:56.

The accident sequence ensues.

There's really not much the PNF can do at this point. At 8:09:05, he transmits a MAYDAY.

———

Obviously there are variations to this, for example it could have been the PF who put the fuel switches back. (In the above scenario, the PF is focused on flying—aviate!—and never turns his head to see the switches.) My goal was simply to set out a possible sequence, to see whether it feels plausible. Remember, as you see other scenarios put forth, that any issues a person could wrestle with would also be distracting. While both pilots would be very focused during the takeoff run, the moment the aircraft lifted off, the PNF could well have mentally relaxed a little, opening an opportunity for the action slip.

Thoughts?

Originally Posted by ManaAdaSystem

A lot of \xabflipping\xbb and \xabflicking\xbb of fuel switches going on. You don’t flick or flip these switches. They require a deliberate movement.

Originally Posted by CharlieMike

A statement that completely underestimates the human subconscious system. You need a deliberate movement to raise the gear or drop the flaps too\x85I\x92d say nearly every operator has instances of pilots accidentally doing one instead of the other. There will be people saying that there is no way you can have such an extreme action slip but I don\x92t think we should ever underestimate the power of the human to do the most random things, even if it is one-in-a-million event.

Originally Posted by enderman

Action slip seems highly unlikely to me. Even if one cutoff switch was moved in response to a gear up request I can\x92t believe anyone would then move a second switch, one second later.

Originally Posted by CharlieMike

I\x92d counter that order of likelihood by suggesting

(1) It\x92s still a likely response to ask that question if your colleague had just switched them off by action-slip.
(2) See my post above. Routine use of these switches is in one \x93event\x94\x85below OAT 40C you start both simultaneously and at shutdown you operate one straight after another.
(3) The interim report seems to leave out all information on verbal exchanges not specifically involved with a response to the abnormal situation.

Not saying you aren\x92t correct, but it doesn\x92t change the order of likelihood in my mind.

Originally Posted by adfad

(1) is true I give you that, but there is no followup "I didn't.. oh crap", denial is a reasonable response if you truly haven't registered doing something, but it is also a reasonable response if you want to confuse to delay

By precedent in routine operations I mean: is there a single example of these switches being cut off at takeoff like this? There is precedent for the wrong engine being shut down in a fire sure, and there is perhaps precedent for mishaps with the fuel switches in other cockpit layouts - but in the case of this layout, with this model of switch or even this 'style' of switch and placement, I cannot find a single example that would come close to the level of catastrophic action slip of pulling out and setting to cutoff both switches one by one.

I think the preliminary report is supposed to present all factual information - they could have left out "why did you cutoff / I did not" - I could understand if they left out sounds that could be ambiguous, perhaps indicating a struggle but not clear enough to present as fact. However, "positive rate / gear up" followed by 2 switches instead of gear handle is completely factual and relevant information, to exclude it makes no sense.

Originally Posted by B2N2

Everything is recoverable given the right set of circumstances.
Given a different set of circumstances at some point the situation is unrecoverable and you become “dead man walking”.
Stalls, spins, unusual attitude recovery, MCAS events, they all become unrecoverable below a certain altitude.
If I had to take a guess I would say 2500-3000’ AGL and this could have been recoverable.

Originally Posted by AirScotia

Sorry to reply twice, but's worth noting that Samaritans responders (Befrienders in the US?) are trained to ask if the caller has considered a means of killing themselves. If they have, they move right up to a red alert. Sometimes the question is the first time the person recognises that they do in fact have a plan ready to go.

Originally Posted by Semreh

Non-pilot here.

For those interested in reading more about 'action slips', including performing one routine function in place of another, the following free-access article goes into more detail:

Wiley Online Library: Oops! I Did it Again: The Psychology of Everyday Action Slips



As other people have perspicaciously pointed out, assuming that it was the Pilot Monitoring that transitioned the Fuel Cut-Off Switches from RUN to CUTOFF, what action would they likely have been attempting to perform at that stage of the flight for an action slip to be a likely possibility?

Alternatively, given that the PM was used to operating simulators, what conditions could have prompted him to do a sequence that was familiar to him of resetting the simulator (including operating the FCS switches), doing things that are inadvisable in a real aircraft?

If these are stupid questions, I apologise for taking up a mod's time processing the comment deletion.

Originally Posted by andihce

Meaning no disrespect to pilots (indeed, quite the opposite), and admittedly I'm no psychologist, but it strikes me that to postulate that a pilot might cause the crash of a large aircraft because of suicidal thoughts is to seriously understate the action taken , because such action also means the likely death of all passengers and aircrew, presumably all or most of whom are perceived as innocent bystanders by the actor. Whatever term you want to apply to that action, it is far more and far worse than individual suicide, and I would think it needs a pretty substantial and convincing body of evidence, including psychological evidence, to explain.

I know such cases have happened (or may have happened, as in MH370), and perhaps cannot be excluded here with what we know at present, but I for one would be far more inclined to suspect something along the lines of the various "brain fart" possibilities that have been mentioned, absent further data.

Originally Posted by AirScotia

Sadly, the evidence is that suicides have usually reached a point where others don't exist.
.....
In the moment, you just want out.