Posts about: "Fuel Cutoff" [Posts: 302 Pages: 16]

Not 'my' XXX ft (my bold in quote)
I read elsewhere in this thread that 'below 400ft (or whereabouts) no actions from the crew' as an SOP. What I read as SLF engineer --> between V1 and 400ft certification flies the AC unless there is failure outside certification bounds in which case we need the professional to attempt to save the day. So... what was the emergency IF hands were at switches area during that phase of the flight?

Read the part that both switches were set to 'off' in the report. Even if they were not and this is aliens, it is documented now.
I wrote that I'm SLF. For me the pilots or whoever is upfront is also a potential failure mode on the system.
I also wrote 'ban jump seating', you missed that.

How do you tell there is an engine fire from the cockpit? Same thing that tells you on the AC side can un-inhibit them. Or add a switch
If there is engine fire alarm at Vr what do SOP say?

FBW control law of AC has several modes that doesn't let pilots do stuff. How do you switch from the one to the other as a pilot? Same can go with engines control.

To avoid misunderstandings: I'm the type that wants human pilots at the front.

That's not an overly detailed description. In fact, and this is the only fact, it doesn't say one word about the locking mechanism of the switches.
I don't know why most of the forum contributors cannot see this.

Winemaker, of course. Or maybe they were already a few days there. Maybe the locking mechanism was loose and started turning, so it wouldn't lock anymore. What the heck. I don't know. Does it really need that much of fantasy to imagine? We all have seen things getting loose with time. It is physically plausible. At least as much as laps or a depressed pilot.

Boeing's whole differentiation from Airbus in design is they want the pilots to have more control. Also this would never pass certification muster. Adding more automation doesnt always make things safer, lots of unintended consequences. At some point you just have to accept when you fly your life is in the pilots hands for good or bad.

Can someone please confirm whether or not the respective fuel cut-off switch is directly connected to the open/closing coils of the fuel valve actuator? Or is there some intermediate control system between the switch and valve actuator?

Something else that has been repeatedly discussed in the three threads...
While there are interposing relays, the signals to the Fuel Metering Unit shutoff valve and the Spar Valve are hardwired from the switches to the valves in question. They don't go through some computer interface that could corrupt the signals.

The recorded switch position data, the recorded engine performance data, the aircraft performance and trajectory after take off, the RAT deployment and open/ing APU inlet, the cockpit voice recording that has been selectively and carefully paraphrased in the preliminary report and the physical and electrical design and separation of the switches and the wiring for each system prove, to whatever standard of proof anyone wants to nominate, that BOTH fuel cut off switches were physically switched OFF 'shortly' after take off, then BOTH switches were physically switched back ON 'shortly' thereafter.

Give the FSC switch/wiring defect theory away, hamsters.

tdracer excellently summarised. But I'll confirm.
The switch is directly connected to the coils of a latching relay. That latching relay is directly connected to the coils of the spar valve. There is no digital logic device in the way,
The position of the switch is monitored (through a different set of contacts) by the EAFR (twice). The position of the spar valve is monitored by the EAFR.
Thus the recorder sees (twice) that the switch is moved, and that the valve moved in response.

I'm sensing that the Journal, while not immune whatsoever to commercial pressures, is well-sourced.

From the article: "The preliminary details have fueled the belief among some U.S. officials that criminal authorities should review the matter, as would likely be the case if the crash had occurred on American soil, people familiar with the matter said." This assertion, stated without attribution, is fairly viewed as having unknown credibility.

But it also might be understood differently when read in a context of the entire reporting which includes these two quite specifically attributed statements:
From the article: "An NTSB spokesman said that [NTSB Chair Jennifer] Homendy has been fully briefed on all aspects of the Air India investigation, including the cockpit voice recording and details from the flight data recorder. Homendy said her goal in working with Indian authorities was 'to quickly determine whether the crash presented any immediate safety concerns to the traveling public.'\x94 (internal quotation as in article)
........
From the article: "The Indian authorities\x92 preliminary report finding that the fuel control switches were flipped in succession, one second apart, suggested a deliberate act, according to Ben Berman, a former senior NTSB official who helped oversee the U.S.-led investigation into the crash of EgyptAir Flight 990 in 1999.

Berman said that, prior to the engines\x92 fuel being cut, the report didn\x92t suggest anything out of the ordinary for what should have been a routine takeoff and climb-out. 'There was nothing to prompt the crew to perform emergency procedures, become stressed, or do anything except rotate the nose up and retract the landing gear, like they had done so many times before,' Berman said." (internal quotation as in article)

The Air Current's reporting just prior to release of the preliminary report - based on unnamed sources possibly with close access to the AAIB - turned out to have been correct. Would NTSB have offered the comments it did, if it believed the Journal was about to publish stuff it was just making up?

Edit: the WSJ also, on Wednesday, published a column by one of its regular staff columnists who thinks pilotless airliners are inevitable and would be a much better system architecture. Perhaps in publishing this reporting about the Air India accident the Journal is hoping to preserve credibility among the industry and regulators, despite the nonsense (imho) of that part of the column (most of it concerns the apparent cause of the accident, which - as some post many many pages ago predicted would occur - becomes supposed justification for Captain HAL).

For reference, here's the datasheet for the family of switches that includes the 787 fuel cutoff switch (4TL837-3D):
https://prod-edam.honeywell.com/cont...iid-148208.pdf
I apologize if this has already been posted.

Extract from a Telegraph article this morning, is this relevant ?.

Indian media, however, reported that investigators were examining potential electrical and digital faults that could have triggered “uncommanded” actions.

“The probe will ascertain the possibility of an ‘uncommanded transition’ of the fuel control switches to the cut-off mode seconds after the lift-off,” an official aware of the investigation was reported to have said.

Just hours before take-off, a pilot flying the same aircraft from Delhi to Ahmedabad noted in the technical log a “stabiliser position transducer defect”, the newspaper said.

The stabiliser position transducer is a sensor that controls the up and down movement of the aircraft’s nose, and transmits the data to flight control systems. The official said the malfunction was checked and the engineer did the troubleshooting.

“The malfunction is a critical issue as it can trigger incorrect responses in flight control, including unintended fuel cut-off signal,” the official was quoted as saying.

It is relevant to understand Indian media are highly unreliable and biased. https://feitoffake.wordpress.com/202...trol-switches/
The same applies to former pilots https://feitoffake.wordpress.com/202...room-in-india/

Very useful, I now know that the required lift of the spring-loaded toggle to change position is only 2.28mm or 0.09in. That's not as much as I thought it would be.

Saying so doesn't make it so. There is nothing "simple" about pilot suicide, major depression is a complex condition to begin with and the aviation context adds multiple complicating layers of conflicting motivation. I have stated before that depression and suicide are being displayed irrationally here by a number of people. It's simply not a magic explanation you can just wave at any behavior you don't understand. That's not how that works.

All known cases of pilot suicide have indicators that are not present here. In some cases (like the often mentioned Germanwings incident) those indicators were such strong evidence that the criminal case was open and shut in days or weeks. Those weren't "simple" cases either, but they had the evidence one would expect from a pilot suffering such a complex condition. Nothing of the sort is known about either the Captain or the FO.

Suicide is almost always the last step in a long history of suffering from (mental) illness. Suicidal ideation is what the medical field calls thoughts (ideas about) suicide. It's a comparably common symptom shown in around 5-20% of adults worldwide with strong variation correlating with external factors, such as economic well being, occupation, stress, etc. Assessed globally Pilots, as far as relevant studies are available, seem to fall into the lower bracket of prevalence of suicidal ideation with a lower than expected prevalence when compared to the general population from their respective country of origin down to the rate observed in the general population of economically stable and strong countries.

Cases where pilot suicide is suspected (any case where at least some level of evidence is present but either no or only an officially disputed final assessment exists) also generally follow the same patterns. Attempts at concealment are known to happen, but make up only 10%-30% of completed suicides in the general population. This does include the gray area of potentially successful concealment which would lead to the assumption of an accidental death.

In almost all cases a recurring pattern is also the topic of certainty. In suicidal ideation it is a very common theme that any issues are projected into the future and the uncertainty of those issues generates anxiety. Many survivors of suicide attempts reveal that they considered the certainty of their own death to be preferable over the continuance of uncertainty and the associated anxiety. While we are far from being able to authoritatively call this a definitive mechanism in the psychological conditions related to suicide it is strongly implicated and subject of ongoing research. My personal way of explaining this to someone unfamiliar with depression is that your brain is quite literally poisoning you and generating so much trauma that the idea of ending it becomes preferable. Patients in this stage of major depression show a determination and rationality in their drive towards that goal that is often the primary source of perceived irrationality from the outside. They routinely ignore any and all information that is not relevant to their goal. The means are often chosen with preference of perceived certainty over any other motivation, including harm to others.

Summarizing:
1. Suicide is overwhelmingly the last step in a history of mental illness and almost exclusively presents without that in cases of immediate, significant and obvious trauma.
2. Attempts of concealment are of low probability in a suicide.
3. Methods of suicide are commonly chosen based on perceived certainty of success.

These indicators are all negative for the Air India accident. There is no indication of a prolonged history of mental illness, there is no immediate, significant or obvious trauma. Theorizing an attempt at suicide by either of the pilots requires the assumption of a major attempt at concealment. And most importantly: The method chosen is not following the pattern of maximizing certainty, the probable reason why all confirmed and even all suspected cases of pilot suicide happened in cruise flight.

The theory of suicide is thus, in this particular case, a bad fit.

If we are assuming an (intentionally) concealed medical condition there are much simpler and more likely candidates available. Any type of cardiac issue could lead to a clot and a stroke. A stroke fully explains what happened here. A clot triggered by the acceleration of the takeoff run could very reasonably present as a stroke in the timeframe given here. If the victim belatedly realizes what happened he may develop the wish to stop the situation, which in a stroking brain could absolutely lead to the shortcut of "turning off the engines is done at the end of flight". Or the stroke victim is trying to hold onto something and grabs the switches relatively close to the relaxed hand position after releasing the thrust levers at V1. Other conditions can rapidly present and impact judgement, motor function, or both. If we are willing to attribute the Captains recent decision to retire and be with his father as a potential change in character we might even fall into a number of neurological conditions that may be causal.

But there are even simpler explanations than a concealed medical condition. Maybe one of the pilots had previously finished recurring training for evacuations on the runway and had discussed this with his colleague ahead of the flight. The final memory item for those is turning off the fuel pumps. This kind of Action Slip is well documented. It's not very likely, thus I have no issue believing no one reported observing that type of a slip in a simulator, but it's not like accidents with this level of weirdness are common. There is however a good indicator here fitting the situation of at least one of the pilots: The Captain may have been preoccupied with his wish to retire soon and spending time with his father. While the latter makes absolutely no sense in a suicide it could be part of the causality for an action slip. Also note this post about inadvertent activation of switches despite majorly different modes of activation.

In the end here are three observations based on the preliminary report:
1. Any type of mechanical fault is unlikely and no immediately supporting evidence has been found.
2. A human factor is currently the most likely candidate for the cause of the accident.
3. The type of human factor is not being speculated upon in the preliminary report.

Note that the report specifically states:
No further reference is made to any medical conditions, which is expected as these would fall outside the guidelines for inclusion in a preliminary report.

Attribution of an unclear accident to suicide is contributing to a problematic pattern of stigmatization and increases the likeliness of concealment of (mental) health issues associated with that stigma. In addition it precludes proper analysis of a potential inadvertent mishandling of controls. Both Airbus and Boeing commonly utilize this position and type of guarded switch. Both are sufficiently protected against accidental movement but nothing else. In many smaller aircraft setting the Master Switch to Off would not lead to engine shutdown. There are even reports of what we could consider negative training, by flight instructors demonstrating this fact by turning the Master Switch off in flight. Other commercial aircraft utilize different schemes, Embraer was mentioned right at the beginning of this thread by moosepileit as requiring Throttle Levers at idle for Fuel Cutoff as well as positioning those switches on the overhead panel .

Having just done a full review of this entire thread with regard to human factors I find it a bit sad to note that from the start there were multiple people with backgrounds in accident investigation present that pointed out human error and gave proper reasoning or even corroborating evidence in the form of accident reports. There are also multiple people repeatedly injecting their theory of pilot suicide either without providing any evidence or referring to baseless rumors from media reports. Notably those same people often rejected any other possibility of human error. They also repeatedly make statements of fact that are contradicted or not covered by the preliminary report. Any discussion of mental health seems pointless at this moment in time since there is no actual interest in the topic beyond occasionally going "It's suicide, duh". If anyone is interested in the topic I can once again only recommend taking a look at the Pilot Mental Health Campaign Research Page and other resources presented there.

I think the other worthwhile takeaway from this thread has been stated rather early, with the very applicable nod to a better layout regarding critical functionality that has no reason to be present in close proximity to regularly used flight controls.

I'm sorry to say that OhForSure's suicide theory fits well because:

1) like many suicidal people, the captain may have planned his death in detail. He would have known that cutting the fuel at this altitude would guarantee that the engines could not produce thrust before the aircraft crashed. He would have known that if the other pilot seized control it would be impossible to land in an area empty of buildings. And he would have known that he would be instantly rendered unconscious upon impact, with certain death at the same moment or shortly afterwards.

2) he may have wanted the investigators not to reach a firm conclusion of suicide so that his family would receive an insurance payout, and his family, friends and colleagues would not be vilified or feel guilty about not noticing his mental condition. His mayday call may have been carefully calculated to deepen the mystery of the final moments. He may have chosen fuel starvation at low altitude rather than a vertical dive from cruising altitude because the latter would have looked more like suicide and he'd have had the additional hurdle of preventing the other pilot from saving the day.

Another collected set of 'maybe' and 'possible' with no actual foundation.

-He could not plan for his death in a situation where there is potential for survival.
-Any investigatory conclusion that the crash was the result of suicide or malfeasance would ensure no insurance payout would be made.
-He could not hope to disguise his actions from being recorded in both data and voice.
-The MayDay' call would cause more suspicion if he had NOT made it.
-A high altitude descent at speed would have been far more likely to end in death, and the cause be less possible to discern.

There's lots, psychologically speaking, wrong with this scenario too. I'd be much more convinced that this was an impulsive act or a psychotic one than that it was a planned suicide, meant to happen this way.

There seem to be two major camps at this stage. The crash was:

1) An intentional act of mass murder/suicide.

2) A mass casualty event caused by a mental health issue, another medical condition or an action slip/brain fart. At any rate, a non-desired outcome from the offending cockpit member's point of view.

Why some of my colleagues would so ferociously be advocating for option #1, I will never understand. Do you believe that the more condemning your language is the more credibility you will achieve with your peers if proven right in the end? I just don't get it. Maybe it's just a case of always being used to getting instant gratification in all aspects of life.
Give it some time. We have heard from very knowledgeable contributors to this thread how an investigation is conducted, maybe show some compassion with the deceased crew, passengers and people on the ground, and give it a rest for a minute?

The flight profile certainly does not indicate any sort of struggle in the flight deck post initial fuel switch "transition" as the wings level/center line tracking would suggest a maximum effort to keep the a/c in the air. That could easily be interpreted as a joint effort to rectify the issue or it could mean that the fuel cut-off switcher was severely incapacitated from that point on, leaving the other member to do his best to fly the Boeing solo.
Either way, a very strange way to commit a premeditated mass murder.

Again, I will not discount #1 but I am still very much "hoping" for #2.

Can you explain me Dave why the industry needs more like her?

She told utter nonsense.

This is the person who said the stuff quoted below. I hope you agree with me the ANA B787 uncommanded dual engine shutdown in 2019 *** after landing *** had nothing to do with a ' similar fuel cut-off malfunction during final approach".
There is also no Boeing software issue in the case of AI171. The ANA B787

ASN wrote: A Boeing 787-8 of All Nippon Airways operating ANA/NH985 from Tokyo/Haneda to Osaka/Itami stuck on runway 32L while landing at Itami due to sudden shut-down of both engines after Thrust Reverser actuation.

Ms Schiavo said:

"As fresh scrutiny surrounds Boeing after the Air India AI 171 crash, aviation expert Mary Schiavo reveals that a similar fuel cut-off malfunction plagued a Japanese Boeing 787 in 2019 \x97 with pilots never touching the controls. Investigators now face mounting questions on why warnings were missed and why Boeing\x92s software may still pose a global threat."

and
Mary Schiavo revealed that a near-identical incident occurred in 2019 on a Boeing 787 operated by ANA during its final approach to Osaka. \x93The investigation revealed the plane software made the 787 think it was on the ground, and the Thrust Control Malfunction Accommodation (TCMA) system cut the fuel to the engines,\x94 she said.
On that occasion, both engines shut down simultaneously, but the crew landed safely. The Japanese aviation authority and Boeing traced the incident to a software fault, not human error. ANA\x92s Dreamliner, carrying 118 people, had to be towed off the runway.

Nonsense. See the headline. Schiavo compares the situation with another B787 with the Air India case. Both are totally different.
Schiavo blames Boeing software.

\x91Pilots Didn\x92t Touch It\x92: Air India Crash Mirrors 2019 Dreamliner Fuel Cut-Off , Expert Says Boeing Software To Blame

I fear we could discuss comorbidities until we're blue in the face. But no, I wouldn't dismiss the possibility of it being suicide, no. I just consider it to require any kind of actual prove instead of prove by the inability to come up with better explanations. As for the topic of concealment: It's obviously a grey area but the previously quoted 10-30% prevalence is based on studies trying to figure out exactly that. I certainly wouldn't feel comfortable opining on that number.

Suicidal ideation does frequently present with both imagined as well as examined scenarios. Especially in more severe cases many victims have a history of attempts. The impulsive variants are typically in lesser severities of depression and are actually more common in people with lower levels of suicidal ideation. It would certainly be the most likely scenario for a suicide that I could come up with. It's especially prone to happen in cases with sudden traumatic events on top of an existing baseline condition but can occur in any other condition as far as I know. It would also fit somewhat with an unremarkable history as a person suffering from mild to moderate depression might consider being able to cope on his or her own. And then obviously be less prepared for a spontaneous urge. The troubling part here is that it would be indistinguishable from an action slip without additional evidence as to the pilots state of mind. The observable scenario would be something like this: Immediately upon reaching v2 the Captain moves both fuel cutoff switches to their off state in quick succession. When queried by the FO he denies having done so and remains passive until impact.

This is a plausible scenario, but also one that would be impossible to determine causally. Try for yourself, but you can use either rationalization for the behavior and even use the same rationalization for the opposite behavior. There is no way to predict how anyone would react in that situation and no way to determine either way what that behavior indicates. Not even moving those switches back into the on position by himself would give a reliable clue as to his state of mind. The report would probably default to Human Error in this case, as the intent could not be determined.
The resulting suggestions, ironically, would be basically the same as well. Ease access to mental healthcare, improve training for avoidance, and most importantly: Improve resilience of systems against this type of action.

Based on the numbers available to us right now I can almost guarantee that if you have taken more than 10 flights in your life one or both of your pilots or colleagues on the other seat suffered from symptoms of moderate to severe depression. And you will with almost absolute certainty never actually know. The true question people need to ask themselves is "Do I want my depressed pilot to have access to psychotherapy or not?"

The displayed EICAS messages are very different when an engine is shut down via the fuel cutoff switch vice other reasons. The EAFR records those messages. I am quite sure they have eliminated the TCMA as a problem in this accident.