Posts about: "RUN/CUTOFF" [Posts: 186 Pages: 10]

The preliminary report narrows things down a lot but not as much as it could have done. The report will have been approved by several people. What we see is their consensus. Why did they choose this version?

The report is written to point the finger directly at: (i) the fuel cutoff switches and (ii) either pilot error or pilot mal-intent using them. The report is not written to point the finger at an electrical or mechanical malfunction.

We have all role-played in our heads what would have been said in the cockpit in different scenarios. The investigating team already knows. They could have disclosed more of the cockpit conversation, which would be a lot of help to us PPRuNers, but didn't need to. They have let Boeing and the type off the hook and put the blame on the pilots. They have fulfilled the primary purpose of an investigation -- to find out what happened.

Interestingly, they did not disclose whether it was error and mal-intent. Perhaps that is because they couldn't answer the grisly question: which is least worst, from the point-of-view of the airline, the victims' families and future customers?

Two posters above have quoted AvHerald's report that "... India's media reports that the investigation is NOT focusing on a human action causing the fuel switches to appear in the CUTOFF position, but on a system failure." One interpretation of this is that the investigation knows all about the human action and that the system they refer to is the industry's approach to pilot mental heath and well-being.

YYZJim

I don't know that we can treat media reports as being authoritative in any way, since the investigation team won't be conferring with reporters, whose likely sources will be in political/agency leadership, and not really in the loop either. But to pose an answer your question as to why the report we have was written in the form it is, I would say that firstly, it will have been intended to cover what the investigation knew to be all available material facts at the time of publication, and secondly, (as I posted earlier), likely to try and ensure the investigation ongoing remains as much in their grasp as possible, rather than being taken over by others.

Perhaps that is the Indian media fooling themselves. Maybe they looked in the mirror and tried to avoid seeing what was there.

In the middle of all hamster wheel posts, this one stands out. However, I do take issue only with the last point reported in this no longer reliable AvH website. Concerning the MN4 processor (Ive been looking into this one extensively prior to the preliminary report), according to the AD cited, MN4 board replacement on the GEnx1B was mandated within 12 years of production, engine that is, not A/C. According to the preliminary report AI171 engine 1 was produced 20 May 2012, engine 2 on 20 January 2013. This means that both AI171 engines were with replaced MN4 boards at the time of event, certainly taking into account that both engines have been mounted onto the aircraft in May and March 2025 respectively.

I'm still not clear on something, no surprise there.

If you are the PF and you are just after rotation, and for whatever reason, the fuel control switches transition to "CUTOFF", when and how do you notice this?
Presumably your hands are on the yoke and you are looking very intently out the windshield. So, to me it seems unlikely that you saw whatever happened to the switches, however they moved.

Do you get a warning indication that the switches have moved? If so, then that would be what I needed to know. You got a warning and therefore you looked right at the switches.

If not, do you just notice that you have lost power? If that is the case, where do you look first? I presume it would be at the engine info gauges/displays.

What I'm getting at is what priority is given to looking at the fuel cutoff switches in this situation?
How long until you look at those switches as the possible cause of the engine problems?

Well this is probably why it took 10 seconds, whole right side of the flight deck would be blacked out. My guess is that the EICAS messages that you see during sim engine fires/relights training helped. Don't have the post but it exists earlier upthread but there is an fuel cutoff EICAS message that happens when fuel switches move. Obviously can never count out a side vision of the PM, especially if its not a traditional movement in that stage of flight.

Not a B787 pilot but many hours on its wide body predecessors.

It is conceivable that you could notice hand movement around the throttle quadrant in your peripheral vision (noone's hands are on the thrust levers between V1 and shortly after takeoff), however even if you didn't, you'd immediately notice the loss of performance. The instinctive reaction is big loss of performance -> quick glance across at instruments -> why are they winding back? Also if the fuel control switches were moved to cutoff you'd suddenly get EICAS messages saying the engines were shutdown. So there are immediate clues and it's only a minor head movement to see where the fuel control switches are because they're right down there behind the thrust levers. Then the immediate action for a dual engine failure, which would by then likely be obvious with both sets of instruments showing everything winding back, is "fuel control switches cutoff, then run". There is no significant pause in that action because it's only to reset the electronic engine controls, so the 10 second gap between setting them back to "run" is not explained by the dual engine failure procedure but perhaps by a startle factor. One way or another, your eyes are going to end up checking where those switches are.

I've been 'arm chair' flying this scenario and I imagine (for me) the sequence would go something like this.

I'm pilot flying, so my gaze and attention is firmly out the front rotating to the planned takeoff attitude.

Initially and in no particular order:
- I would feel the loss of thrust as a sudden loss of acceleration.
- There would be a significant nose down pitch trim change that I would feel through the yoke.
- There would be lots of audio cues: Changes in engine and air conditioning noises. Lots of click-clacking as electrical relays change state with the loss of electrical power.

My eyes would be drawn inside. I would notice blanking of some of the displays and then look to the EICAS display. My first thought would be probably that we have suffered a major electrical malfunction. There would be lots of messages. I'm not B787 endorsed, but presumably close to the top of the messages would be ENG SHUTDOWN. This message is shown when 'Both engines were shut down by the fuel control switches or the engine fire switches.'

I think I would then look at the fuel control switches and seeing them both in the cutoff position I would say 'why did you cutoff' or stronger words to that effect.

After that it all depends on the response of the other pilot. If they are uncooperative, I would be putting the fuel control switches back to run. All whilst frequently checking and adjusting my flight path.

With all the ‘experts’ swimming about on this thread, I’m very loathe to dip my toes in the water for fear of sharks but…

Having read the vast majority of postings here on this accident, plus the prelim report, I can’t see how anyone could dispute that ‘someone selected both FCS’s to cutoff Immediately after lift off and before gear retraction’. Which, as all have said, begs the question, was it intentional? A brain fart? Or a “I gotta do this now because of a perceived problem”? I can’t think of any other option.

Like all Boeing pilots (current or retired) we’ve all had a quick and dirty education on a system called MCAS - which is of course a 737 Max issue, but…one does wonder.

The accident aircraft had a stabilizer snag on the previous flight. The accident crew would’ve noted it in the log. Is there a chance that, just at lift off the EICAS stab warning/caution reappeared and the PM thought it would be pre-emptive to turn off the stab trim switches? BUT…muscle memory, startle factor, etc, he grabbed the wrong (but more familiar) nearby switch(es) and selected them. In the ensuing maelstrom, the gear was forgotten, the PM desperately tried to put the FCS’s back to RUN, the PF was struggling with a blank panel but it was too late airspeed and altitude were heading south and… they flew directly to the crash site.

Grasping at straws, I toss this hypothetical scenario into the pool - probably because I just can’t get my head around the ‘intentional’ option.

Now…where did I put the shark repellant.

This seems to quite clearly answer the question: (from the prelim report)

That's the Embraer option.

The other option I can imagine is a mechanical stop with an override button, like the landing gear lever. Can't switch the fuel levers off unless you're slow and on the ground, the engine is failed or on fire, or you push override.

bluemic

How\x92s the water in that shark infested sea?

When I read that on the previous sector the aircraft had a stab issue written up I wondered the same thing. It\x92s a fanciful theory but they all are. I\x92m leaning towards the action slip \x93brain fart\x94 although why might always be the subject of speculation. Assuming that the captain did place the fuel control switches to cutoff just after rotation then whatever the explanation will most likely defy logic.

Incidentally this tragic accident wasn\x92t discussed that much in my company even though it operates the 787. I think there\x92s a realisation that it would be pointless speculation until there is the final report. What was noticeable early on is that we\x92re no maintenance actions mandated by Boeing, GE, the FAA etc. Equally nothing from a flight ops perspective.

The problem with the switches with hinged covers is that they have a single, "safe" position when they're covered. But the fuel switch is safe at CUTOFF when parked, and safe at RUN when the aircraft is operating, so that won't work.

In the last 48 hours I have personally placed four (4) B787 fuel control switches from RUN to CUTOFF.
And as I did so, I had to think of this accident.
I struck me that in my personal way of operating in a cockpit environment, the switching of these fuel control switches is SO deliberate.

Even for me, a regular airline commander. It struck me that I simply can not fathom or believe the scenario wherein a collegue of mine can \x93accidentally\x94, as a slip of mind, place those switches in a position they don\x92t belong.
And I don\x92t buy the failure of one switch, or it\x92s wiring, on the most critical moment in flight.
Let Alone Both At The Same Time.

There are ways to have gates that can be closed in either position (and are perhaps spring-closed), but either they are going to be left open, are a PITA to operate a switch single-handedly, or operating the guard will become part of the muscle memory for operating the switch.

I would agree but what do you imply then?

They are usually such nice sharks.

What is known so far certainly does defy logic but I struggle with the brain fart idea. Firstly (noting that the initial report does not mention positive rate or gear up calls) I can’t see any action cue for the PM to do anything at all at the time the switches were moved to CUTOFF. If some sort of random disorientation action is postulated then you’d have to ask why did it occur at that critical moment and not 30 seconds earlier or 30 seconds later?

Secondly, I can’t be the only one who has operated a control and then perceived an unexpected set of visual, audible or physical responses from something unrelated and instantly thought WTF have I just done followed by an immediate re-check of that action? Although the initial report is notable for what it does not say I can’t see the flat denial of any action is what would be expected given the plethora of cues in that cockpit following the operation of the switches.

This has been discussed to death previously. I suggest looking for tdracer's excellent insights into FADEC design and implementation. From the beginning we've been discussing various very rare types of circumstances. Based on the preliminary report we can now lay most of those to rest.

Which actually brings me to this one because I would like to ask for a bit of clarification: By "fuel switch discrete" are you referring to the Fuel Control Switches discussed in the preliminary report?
I would assume from your statement, that if a mismatch in the NC/NO signal on the switch was detected the FADEC would not direct the Fuel Cutoff Valves to close (as far as the types you are familiar with are concerned), is that correct?

The report states:
So this would then mostly preclude the possibility of one or both switches being faulty electrically.

The report then states:
There is a 10 second gap between cutting fuel and re-enabling it and a 4 second gap between switches during re-enabling. Is there a mechanical reason why these switches would be slower to operate in either direction? There are obviously reasons such as startle factor and stress that might negatively affect the speedy operation of switches by anyone, but I am nonetheless curious if this might not be a pointer to some sort of mechanical issue after all, such as asymmetric wear or FOD.

For the action slip theory, while worth of considering, I have one question. That is that both switches are reported to be moved to CUTOFF at practically the same time, quote "within 0.1 seconds". You can not move those switches one after the other in 0.1 seonds (grip one, pull it, move it, let loose , grip the other one ...).

Question: is it an often encountered practice when arriving at the stand, to shut-down both engines simultaneously? The switch design seems to try to prevent simultaneous action. But we are humans, right?

Why this is relevant. Because if normally you do two actions, maybe with 2..5 seconds gap between them. It would be unlikely that you would shut down both engines instead of gear up. One, yes, on a bad strange day, but not both of them. Except ... you got a habit and always Cut-Off both engines in one single go.

The report says '01 seconds'. You mind has put in the decimal point.

Given sampling rates, it's been established here that this is anything up to 2 seconds.

The facts of the case are: that the FDR recorded that the switches were moved from RUN to CUTOFF, that the engines shut down, that one pilot accused another of having set the switches to CUTOFF, and that subsequently they were set back to RUN and that at least one engine had started to recover before impact.

Think what it would take for you to verbally accuse your colleague of having shut the engines down seconds after liftoff. I hope you agree that looking and seeing that the switches are set to CUTOFF is a bare minimum for you to say something like that.

Any theory where there is some sort of short-circuit or anything like that is a non-starter for this reason. It does not accord with what is on the CVR. The one and only thing that jibes with both the FDR and CVR is that the switches were physically moved from RUN to CUTOFF. The only remaining argument is whether this was done deliberately or as part of some monumental brain fart. I just don't see how it is possible to argue anything else. Even in some incredibly unlikely event where two switches malfunction at once, it is near impossible that one pilot would accuse another of cutting off fuel to the engines without visual evidence to back him up. Either the switches were in fact switched to CUTOFF or you are left explaining not one but two independent and virtually impossible events.