August 07, 2025, 09:06:00 GMT
permalink Post: 11934511
"...and here is my concern with our assumption of intent from evidence of action."
It is worth pointing out that action slips are actually incredibly common but rarely critical - or reported - events. Suicide attempts, by their very nature, have a significantly higher profile. Looking at the literature, action slips on the flight deck are actually pretty common but usually trivial - and that's the ones that get reported. Dangerous action slips are common enough that Airbus have openly available training material on them. Action slips that lead to situations that can't be recovered from are always going to be remarkably rare in an industry that goes out of its way to get the ergonomics right to avoid action slips as a result of designer error. A good example would be the similarity of location, action and shape of the flaps and undercarriage of the B17. The flight deck is one of the few places deliberately designed to make action slips harder to be dangerous and this shows how common they have been.
Action slips occur all the time - most of us have had a few - and used to be far more common in flight before aircraft were designed to avoid them. Suicide attempts remain remarkably rare, attempts with no clear buildup (that can at least be unearthed later) are rarer still and suicide attempts on takeoff are not something I can find online.
So if the investigation is left unable to infer intent from action, it's clear which intention is more likely and also which is more visible.
It is worth pointing out that action slips are actually incredibly common but rarely critical - or reported - events. Suicide attempts, by their very nature, have a significantly higher profile. Looking at the literature, action slips on the flight deck are actually pretty common but usually trivial - and that's the ones that get reported. Dangerous action slips are common enough that Airbus have openly available training material on them. Action slips that lead to situations that can't be recovered from are always going to be remarkably rare in an industry that goes out of its way to get the ergonomics right to avoid action slips as a result of designer error. A good example would be the similarity of location, action and shape of the flaps and undercarriage of the B17. The flight deck is one of the few places deliberately designed to make action slips harder to be dangerous and this shows how common they have been.
Action slips occur all the time - most of us have had a few - and used to be far more common in flight before aircraft were designed to avoid them. Suicide attempts remain remarkably rare, attempts with no clear buildup (that can at least be unearthed later) are rarer still and suicide attempts on takeoff are not something I can find online.
So if the investigation is left unable to infer intent from action, it's clear which intention is more likely and also which is more visible.
Last edited by Subsy; 7th August 2025 at 09:52 .
Subjects
Action slip
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August 07, 2025, 13:13:00 GMT
permalink Post: 11934640
Subsy: good points all.
What gets me, with the info I have available so far, is the reported delay in turning the fuel back on. This is a bit more striking given that the verbal challenge "why did you turn them off" got "I didn't" as a reply.
My experience with action slips is that "Ooh, sheet, moved the wrong thing, fix it!" is the more common reaction or behavior.
In the case of this flight, each bit of delay in getting the fuel flowing again made the chance of a quick enough relight to salvage the error (if error it was) more remote.
I think someone in a previous thread told us that they tried to salvage this scenario in the sim - fuel off about 3 seconds after takeoff - and found the results unsuccessful, but I can't remember who it was.
I have no interest in that TV show, given the avalanche of info and discussion here on PPRuNe since this tragic crash occurred.
What gets me, with the info I have available so far, is the reported delay in turning the fuel back on. This is a bit more striking given that the verbal challenge "why did you turn them off" got "I didn't" as a reply.
My experience with action slips is that "Ooh, sheet, moved the wrong thing, fix it!" is the more common reaction or behavior.
Spoiler
In the case of this flight, each bit of delay in getting the fuel flowing again made the chance of a quick enough relight to salvage the error (if error it was) more remote.
I think someone in a previous thread told us that they tried to salvage this scenario in the sim - fuel off about 3 seconds after takeoff - and found the results unsuccessful, but I can't remember who it was.
I have no interest in that TV show, given the avalanche of info and discussion here on PPRuNe since this tragic crash occurred.
Subjects
Action slip
Relight
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August 07, 2025, 22:40:00 GMT
permalink Post: 11934926
Having gone on countless flight tests during my career, I was always impressed by the competence and abilities of the Boeing Flight Test Pilots. Most of the flight tests I participated in involved at least one engine shutdown and windmill relight (part of our standard 'First of Model' FADEC software cert flight). The pilots would always use extreme care to make sure they got the correct engine - including putting their hand on the fuel switch and having the other pilot
confirm
it was the correct switch before setting it to CUTOFF.
But even Flight Test pilots can have a brain fart. Didn't happen to me, but it did happen to one of my best friends. They were doing in-flight start testing of the 757/RB211-535 (and the Rolls engine is a bit notorious for being a fickle in-flight starter). They were doing a corner point condition when the test engine went into a hot start. One of the observers said something like 'it's gone hot, shut it down'. The left seat pilot calmly reached down and shutdown the good engine
. Fortunately they were at about 30k, and they were able to recover and get both engines restarted before losing to much altitude.
I was told the Flight Test pilot in question was immediately demoted from "Experimental Flight Test" to "Production Flight Test" (where they do routine shakedown flights of new production aircraft prior to delivery).
But even Flight Test pilots can have a brain fart. Didn't happen to me, but it did happen to one of my best friends. They were doing in-flight start testing of the 757/RB211-535 (and the Rolls engine is a bit notorious for being a fickle in-flight starter). They were doing a corner point condition when the test engine went into a hot start. One of the observers said something like 'it's gone hot, shut it down'. The left seat pilot calmly reached down and shutdown the good engine
. Fortunately they were at about 30k, and they were able to recover and get both engines restarted before losing to much altitude.
I was told the Flight Test pilot in question was immediately demoted from "Experimental Flight Test" to "Production Flight Test" (where they do routine shakedown flights of new production aircraft prior to delivery).
BTW, I was flying in a GA aircraft out of Renton (complicated story that had to do with non-rev travel closing up out of SEA, so my brother flew us to PSC which had good availability) and we thought it odd that there was a bit of hoopla going on ... but then realized it was the first flight of 757-300.
Last edited by hulkster; 8th August 2025 at 01:10 .
Subjects
Action slip
Engine Failure (All)
Engine Shutdown
FADEC
Fuel (All)
Fuel Cutoff Switches
RUN/CUTOFF
Relight
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August 08, 2025, 09:24:00 GMT
permalink Post: 11935104
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Action slip
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August 08, 2025, 14:11:00 GMT
permalink Post: 11935237
....What gets me, with the info I have available so far, is the reported delay in turning the fuel back on. This is a bit more striking given that the verbal challenge "why did you turn them off" got "I didn't" as a reply.
My experience with action slips is that "Ooh, sheet, moved the wrong thing, fix it!" is the more common reaction or behavior.
My experience with action slips is that "Ooh, sheet, moved the wrong thing, fix it!" is the more common reaction or behavior.
If we take it as read - which I do but some clearly don't - that the preliminary report contains all the pertinent details as known at the time it was written, then that delay is rather inexplicable. The absence of any reported further confrontation or verbal exchanges on the flight deck rather suggests the pilots were not sure what had happened.
Even if it is taken as read that one pilot was acting intentionally, unless their hand covered the switches - in which case surely there would be some audible action or demand by the other - it would not likely take that long to act and correct the problem.
Subjects
Action slip
Preliminary Report
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October 02, 2025, 17:31:00 GMT
permalink Post: 11963239
I watched it last night - nothing new or that hasn't been discussed endlessly here. Reasonably even handed, although I didn't like all the attention to the 737 MAX fiasco (IMHO, a Red Herring with regard to this crash).
Go into some detail regarding the possibility of pilot suicide (although not much attention to the "brain fart" possibility) - with the obligatory rebuttal from another pilot.
Lots of interviews with grieving relatives.
Go into some detail regarding the possibility of pilot suicide (although not much attention to the "brain fart" possibility) - with the obligatory rebuttal from another pilot.
Lots of interviews with grieving relatives.
Subjects
Action slip
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October 02, 2025, 18:21:00 GMT
permalink Post: 11963266
I watched it last night - nothing new or that hasn't been discussed endlessly here. Reasonably even handed, although I didn't like all the attention to the 737 MAX fiasco (IMHO, a Red Herring with regard to this crash).
Go into some detail regarding the possibility of pilot suicide (although not much attention to the "brain fart" possibility) - with the obligatory rebuttal from another pilot.
Lots of interviews with grieving relatives.
Go into some detail regarding the possibility of pilot suicide (although not much attention to the "brain fart" possibility) - with the obligatory rebuttal from another pilot.
Lots of interviews with grieving relatives.
On a side note, I really would have hoped, that on this, a professional forum there would be a more appropriate means of describing a Cognitive lapse.
Subjects
Action slip
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October 02, 2025, 19:30:00 GMT
permalink Post: 11963302
On a side note, I really would have hoped, that on this, a professional forum there would be a more appropriate means of describing a
Cognitive lapse.
Last edited by T28B; 2nd October 2025 at 19:55 . Reason: brackets included this time
Subjects
Action slip
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October 02, 2025, 19:53:00 GMT
permalink Post: 11963312
For Abbas Ibn Firnas, and your objection to using the well worn and easily understood term "brain fart"
If you have read this whole thread, you'll find that some of our contributors use the term
action slip
.
(The above post is from much earlier in the thread, numerous others subsequently also used that term).
As pilots (and other professionals in the industry) are human, they also use less formal terms from time to time.
(The above post is from much earlier in the thread, numerous others subsequently also used that term).
As pilots (and other professionals in the industry) are human, they also use less formal terms from time to time.
Subjects
Action slip
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October 03, 2025, 05:56:00 GMT
permalink Post: 11963517
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Action slip
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October 03, 2025, 11:17:00 GMT
permalink Post: 11963663
I have rebuilt the site that organises this thread by subject here:
https://paulross.github.io/pprune-th...171/index.html
Changes:
- Build threads up to October 03, 2025, 05:44:00 GMT (built on October 03, 2025, 10:04:00 GMT).
- Added: "Brain Fart" and "Cognitive Lapse" to "Action Slip" subject.
- Subjects added: "Discovery Channel".
- "Likes" are available on the currently open thread.
- You can now respond in pprune to any post on my site under the appropriate subject by clicking the link under the post. This quotes the original post.
Project is here: https://github.com/paulross/pprune-threads
Raise issues here https://github.com/paulross/pprune-threads/issues or PM me.
Changes:
- Build threads up to October 03, 2025, 05:44:00 GMT (built on October 03, 2025, 10:04:00 GMT).
- Added: "Brain Fart" and "Cognitive Lapse" to "Action Slip" subject.
- Subjects added: "Discovery Channel".
- "Likes" are available on the currently open thread.
- You can now respond in pprune to any post on my site under the appropriate subject by clicking the link under the post. This quotes the original post.
Project is here: https://github.com/paulross/pprune-threads
Raise issues here https://github.com/paulross/pprune-threads/issues or PM me.
Subjects
Action slip
Discovery Channel
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October 03, 2025, 11:22:00 GMT
permalink Post: 11963667
I have gathered all the posts mentioning "Action Slip", "Brain Fart" and "Cognitive Lapse" on my site that organises this thread by subject , specifically here: https://paulross.github.io/pprune-th...ion_slip0.html
Subjects
Action slip
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October 03, 2025, 17:36:00 GMT
permalink Post: 11963896
Only adding to comments above… total waste of TV time. All Emotional interviews and rehashing of facts known long ago. I got so bored it never saw the end, as it was obviously just cast as a tear-jerker and not informative at all. No new facts or suppositions which is probably the truth in the circumstances.
With regard to my use of the term "brain fart" - I have never, ever referred to myself doing something stupid as an 'action slip' - I always say I had a 'brain fart' (or perhaps a 'senior moment').
I don't really consider it disrespectful to referrer to someone else doing something stupid with the exact same term I'd use to describe myself doing the same thing.
You are free to free differently.
Subjects
Action slip
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November 28, 2025, 19:32:00 GMT
permalink Post: 11997347
There are no known ways that a 'core' system fault could shutdown the engines.
I do wonder about the stab system faults - although apparently corrected, a good pilot would have reviewed the log and known there had been issues. It might have left him 'pre-loaded' to take action for a stab system problem - which turned into an 'action slip' of moving the fuel levers.
Subjects
Action slip
FDR
Fuel (All)
Fuel Cutoff Switches
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November 28, 2025, 21:11:00 GMT
permalink Post: 11997408
I do wonder about the stab system faults - although apparently corrected, a good pilot would have reviewed the log and known there had been issues. It might have left him 'pre-loaded' to take action for a stab system problem - which turned into an 'action slip' of moving the fuel levers.
Subjects
Action slip
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January 24, 2026, 20:21:00 GMT
permalink Post: 12026564
Non-paywalled version:
https://www.aol.com/articles/sabotag...060100148.html
There's the old "the RAT deployed early" (assuming it always takes a full 6 seconds to spool up), the water leak, the "can't move both switches in a second", and new "the aft FDR looks like it burned before the crash". And this, which is as yet unsubstantiated, and is likely not relevant at all:
There's the old "the RAT deployed early" (assuming it always takes a full 6 seconds to spool up), the water leak, the "can't move both switches in a second", and new "the aft FDR looks like it burned before the crash". And this, which is as yet unsubstantiated, and is likely not relevant at all:
whilst intentional action is the most obvious explanation one can’t ignore data and technical grounds if one is also going to dismiss counter theories on technical grounds
I still don’t believe we have got a clear answer on the recording interval of the engine cutoff switch channel, if it’s 1s then the ‘debunking’ by saying it can be done very quickly is moot as (near) instant would record as 1s I believe
I still don’t believe we have got a clear answer on the recording interval of the engine cutoff switch channel, if it’s 1s then the ‘debunking’ by saying it can be done very quickly is moot as (near) instant would record as 1s I believe
and the RAT element is obviously very relevant, if RAT deployment is not recorded then one has to infer when it deployed based on when it delivered hydraulic/electric capability. And this will come down to counting seconds, any indication that the RAT may have deployed before the fuel cutoffs were recorded as moved is obviously hugely consequential
The engines ran down after the switches were recorded moving. Even if the RAT deployed, that does not suggest that the crew switched the engines off because of an engine failure.
No crew is going to shut down the engines down simply because a RAT deploys unexpectedly.
it’s easy to dismiss these narratives as vested interests but let’s be honest everyone has a vested interest here and blaming the pilots has been the go to when in doubt for a very very long time- probably as long as aviation has existed
in the absence of explicit evidence (does the CVR have more to tell?) of deliberate action or pre-planning this is a horrifically complicated investigation as there will always be plausible deniability on all sides and different courts/judges will rule on it very differently based on their own biases and views
in the absence of explicit evidence (does the CVR have more to tell?) of deliberate action or pre-planning this is a horrifically complicated investigation as there will always be plausible deniability on all sides and different courts/judges will rule on it very differently based on their own biases and views
I don't think you can or will effectively prove whether it was intentional or some kind of an action slip, and by which pilot.
I think the accident report will be able to very clearly and with no reasonable doubt show that the switches were physically moved.
From the article:
The alternative is
too awful for them to contemplate
: that one of the pilots murdered hundreds of people as collateral damage in a suicide.
Because the aft flight recorder was destroyed, investigators cannot retrieve the one piece of information that it alone contained – the moment it stopped working, which might have provided a vital clue about a fire or electrical failure in the moments before the crash.
The aft EAFR was substantially damaged and could not be downloaded
through conventional means.
The CPM was opened to inspect the memory card. The damage was extensive.
Last edited by Someone Somewhere; 24th January 2026 at 20:32 .
Subjects
APU
Action slip
CVR
DFDR
EAFR
Electrical Failure
Engine Failure (All)
FDR
Fuel (All)
Fuel Cutoff Switches
NTSB
Preliminary Report
RAT (All)
RAT (Deployment)
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January 24, 2026, 22:22:00 GMT
permalink Post: 12026621
The alternative is
too awful for them to contemplate
: that one of the pilots murdered hundreds of people as collateral damage in a suicide.
paulross put up a site that allows one to go through the details. Suggest that you enlighten yourself. There is a link to it in this very thread.
I still don’t believe
They are not accepted as valid.
Nothing new under the sun.
It's the internet, Jake.
There is a more productive line of thought as regards action slips, but unfortunately for the accident investigation board both of the pilots are dead and thus a bunch of the human factors pieces can't be put into the jigsaw puzzle.
The picture will remain incomplete, even though they do have the CVR transcript to work from.
(And no, I have no indication that the AAIB has released that transcript, nor do I believe that they will).
Last edited by Lonewolf_50; 24th January 2026 at 22:42 .
Subjects
AAIB (All)
Action slip
CVR
Human Factors
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January 24, 2026, 22:54:00 GMT
permalink Post: 12026634
The alternative is
too awful for them to contemplate
: that one of the pilots murdered hundreds of people as collateral damage in a suicide.
Travel by air is incredibly safe today because we've had a century of accidents to study, understand, and put things in place to prevent a future occurrence - be it improved flight deck procedures, better aircraft design of systems and redundancy, or safety systems like TCAS and GPWS (or in many cases, some combination of those).
But collectively we don't have a clue what to do about something like Germanwings. Oh sure - various steps were taken such as never leaving one pilot alone in the flight deck - but that's basically just 'feel-good'. We did something so now everyone can feel safe again.
When the awful truth is that if one of the pilots decides he/she wants to crash the aircraft - there is
-all that we can do to stop them. It doesn't particularly matter the motive - suicide, religious nuttier, some political motive, etc. - if a pilot wants to crash bad enough, they'll find a way.
BTW, I still lean towards the 'action slip' explanation - but we're not much better at preventing than preventing a future intentional action crash.
Subjects
Action slip
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January 25, 2026, 02:06:00 GMT
permalink Post: 12026705
I still lean towards the 'action slip' explanation - but we're not much better at preventing than preventing a future intentional action crash.
From training I have done with other pilots, I have discouraged "fast fingers" so I'm nearly always content if there is a "Identify, confirm, (agree with the other pilot) then act" process before critical controls are operated. That couple of seconds to be sure and correct is nearly always worth the short wait. I think in terms of the second of two engine being shut down, it's worth waiting the extra couple of seconds to get it right!
Subjects
Action slip
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January 25, 2026, 06:41:00 GMT
permalink Post: 12026747
Selecting the fuel system controls (i.e. fuel pumps) off will not work
AFAIK
, as the engines will gravity/suction feed under most circumstances.
Fire handle will work as the backup shutdown. As the fire handle is not regularly used, I don't think action slips are inadvertently going to operate them.
Option A is to ignore the cutoff switch unless the thrust lever is at idle - Embraer already does this.
Option B is a landing-gear-lever style solenoid interlock on the cutoff switches. Unless the aircraft is on ground and slow, that engine has failed, or that engine has a fire warning, you have to push override.
I think Jeju have fairly conclusively shown that you need to not switch an engine off within ten seconds.
If you want a system to stop the pilot(s) deliberately and competently crashing the plane (as is posited for MH370), it gets much much harder. I posted some thoughts about that in the 'too much automation' (IIRC) thread, but it boiled down to needing a lot of redundancy and a self-flying aircraft. Enforcing 'must have M of N enabled' is the easy part.
Fire handle will work as the backup shutdown. As the fire handle is not regularly used, I don't think action slips are inadvertently going to operate them.
Option A is to ignore the cutoff switch unless the thrust lever is at idle - Embraer already does this.
Option B is a landing-gear-lever style solenoid interlock on the cutoff switches. Unless the aircraft is on ground and slow, that engine has failed, or that engine has a fire warning, you have to push override.
I think Jeju have fairly conclusively shown that you need to not switch an engine off within ten seconds.
If you want a system to stop the pilot(s) deliberately and competently crashing the plane (as is posited for MH370), it gets much much harder. I posted some thoughts about that in the 'too much automation' (IIRC) thread, but it boiled down to needing a lot of redundancy and a self-flying aircraft. Enforcing 'must have M of N enabled' is the easy part.
Subjects
Action slip
Fuel (All)
Fuel Cutoff Switches
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