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

Having read through most of the posts in this and the other threads, and the preliminary report a few times in parts, am mystified by this:

The Preliminary Report states: "The CCTV footage obtained from the airport showed Ram Air Turbine (RAT) getting deployed during the initial climb immediately after lift-off (fig. 15). No significant bird activity is observed in the vicinity of the flight path. The aircraft started to lose altitude before crossing the airport perimeter wall."

Does this mean the RAT deployed "immediately after" in the sense of within 1 second after lift-off?

We, as a group, certainly seem to be interpreting the "immediately thereafter" in a prior paragraph to mean that the E1 and E2 fuel cutoff switches went RUN -> CUTOFF within 1 second or so after max airspeed of 180kts at 08:08:42.

The prior paragraph for quick ref:
"The aircraft achieved the maximum recorded airspeed of 180 Knots IAS at about 08:08:42 UTC and immediately thereafter, the Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position one after another with a time gap of 01 sec. The Engine N1 and N2 began to decrease from their take-off values as the fuel supply to the engines was cut off."

Additionally, have to say, this PR has a few major weaknesses in it:
- no timestamp for RAT deployment, though RAT hydraulic power coming online has one; also is it for initial power or rated power?
- no timestamp for the pilot conversation about 'cutoff', though it is provided for the MAYDAY.
- no timestamps for E1/E2 Fuel Cutoff Switches going from RUN -> CUTOFF, though they're provided for CUTOFF -> RUN.

Absolutely. The attempted reading of tea leaves to interpret what the authors may have meant beyond what they said, or what they intended to convey by not saying something else, may be fun for some, but it really contributes nothing to understanding this crash.

We know with reasonable (although not perfect) certainty that the fuel control switches were placed in CUTOFF almost immediately after rotation and were later moved back to RUN. We do not know who did that or why it was done and we don't have nearly enough information to answer those questions with any confidence.

The authors of the report have access to the full cvr. They have chosen to only release a synopsis of one fragment. Who knows what the rest of the cvr discloses but the decision to release that one fragment must be to convey an understanding...they want it known.

SLF here, but I did read all 3 threads. To me, this doesn't seem likely. But it got me thinking, what about the fuel switches being partially cross-connected left to right and right to left? If each of the 8 channels (4 for each switch) has its own connector, it could be possible. From what I understood from earlier posts, from the 4 channels of each switch, there are 2 can shut down an engine. If that's the case, assuming some cross-connection, a single switch movement might be able to affect both engines.

But, even if this were possible, there are problems with this hypothesis too. The problem would most likely be discovered during engine startup, if the engines are started one by one, not at the same time, as they probably wouldn't start unless both switches are set to RUN. And not sure how this would fit the various delays recorded on the FDR. And you still need something/somebody to move at least one of the switches after rotation to trigger the issue. Both switches being moved by the pilots still seems much more likely to me than some technical issue.

"Software faults" do not usually come out of the blue, for no particular reason. Just because it's recorded by software it doesn't mean that it's not something hardware related that triggers it. In a previous reply, not sure if in this thread, it was mentioned that the message meant that there was implausible data coming from those STAB cutoff switches, if I remember correctly. Something like a channel showing both on and off at the same time, or the other way around, or some other inconsistency. That could have been an intermittent issue, that might indeed not be reproducible with a BITE test, and just be cleared. But if the STAB cutoff switches did indeed have a problem, or one was suspected due to recurring reports, is it really so unlikely that they might try to look for some hardware issues, such as a loose connector? For the Lion Air accident involving MCAS, after repeated issues during previous flights, they did exactly that: disconnected and reconnected some connectors to check for issues, among other things.

Software faults, or non correlated maintenance messages can be induced by other factors other than a hardware fault.
EG. GPS faults are common among aircraft that fly around Turkey and other troublesome areas of the world due to GPS 'spoofing' or jamming. The problem is known and a procedure to reset the fault and verify that there is no 'hard' fault hidden in the hardware is used every day.

As I posted earlier in this thread, the Stab Trim (Posn) XDCR status message can be deferred under the MEL with a maintenance procedure that does not involve touching those switches.

Simply calls for both fuel switches to be moved to CUTOFF then back to RUN.

Literally what the Preliminary Report says happened. Even the Pilots' exchange fits within this context.

In my opinion, not enough attention is being paid to why the Pilot Monitoring might have *had to* execute the memory items for dual-engine failure.

Likely because the FDR readout showed the engines at the appropriate takeoff thrust, then the switches move, takeoff thrust goes away. Switches move back to RUN and the quick restart begins.

Generally don't think it's a good idea to reply to own posts, but in this case wanted to keep things in context. A few interesting items of note:

1. ADSB readouts - according to FlightRadar24, the last ADSB transmission was at 71ft AGL. Is that significant given the RAT is seen already deployed at 150ft AGL per the estimate above? At 71ft AGL, the wheels are about 40-50ft off the ground, assuming aircraft attitude is unchanged between there and this image. Is that 1 or 2 seconds after rotation? Does this imply electrical issues?
1a. The timings for ADSB transmissions outlined by MrShed are not in sync with the estimates above - people have talked about a time shift in this thread. I do believe ADSB timestamps are by the receiving station.
2. The preliminary report timings from the EAFR for E2 fuel cutoff switch RUN -> CUTOFF to the RAT supplying hydraulic power disagree with the lower end of the 4-7s estimate above, and are only consistent if this picture was taken 6-7 seconds after rotation, in my opinion, because of the time (4-5s) it would take to cut off the fuel to E2, spool down to where the VFSGs stop providing AC power, and RAT deployment.
3. The Preliminary Report mentions that the RAT deployed "immediately after" lift-off. Again, I have to wonder, why didn't they provide the RAT deployment timestamp, even relative to rotation? If this is in fact the case, does this imply electrical issues, in line with the last ADSB altitude reading?

FR24 article https://www.flightradar24.com/blog/f...rom-ahmedabad/

Hi appruser ! I have quoted Pip_Pip 's post above because the position provides a better means to link ADS-B data to the sequence of events, since it's coming directly from the aircraft. The time stamp comes from the volunteer-run receiver, which might experience clock drift. Based on the public CCTV video, we also have a rough triangulation for the rotation, which occurs next to the high-speed turnoff for the third taxiway.

Note that the good folks at FR24 did not apply temperature correction to the barometric altitude (they corrected for air pressure and runway elevation); pilots on pprune have done the corrections themselves and arrived at slightly different values, so take those altitude numbers with a grain of salt. Note also that the 787 sends altitude in 25 ft. increments, and I don't know how these are rounded (up, down, nearest).

We do not know how long the RAT has been deployed in this photo, we only know it can't have been deployed later. I have learned on this thread that the CUTOFF switch will also cause the VFSGs to disconnect, i.e. the B787 systems will electrically isolate the engine from the power buses before it has spooled down. With a dual failure, this would leave the main buses unpowered in short order, so if all of this is correct, the RAT would have clonked into place very soon after the second engine was cut off. This would not depend on the turbine speed.

I personally do not know what items are logged on the flight recorder, but I imagine RAT deployment was not among them. If so, the conditions for its deployment would be logged, but it requires an analytical step to conclude it did, and a preliminary report typically has no analysis at all. Hydraulic pressure to the flight controls is likely logged, so the RAT delivering hydraulic power would be a matter of record.

Where is the RadAlt antenna on a 787? Is it in the nose, or further back between the main gears?

Thirsty , any notion of an electrical fault must contend with fact that it affected several poles on two switches at nearly the same time in such a way that the signal remained valid; i.e. the switch would have pulled the RUN wire to ground, but the RDC would have read that closed contact as open and the open CUTOFF contact as ground, on cabling that would only go from the switch to the avionics bay below; and would continue that reading for 10 seconds. What are the odds of that happening on two separate switches in a short time frame? with no other electronics reported affected? and (presumably) no history of issues with these switches on that aircraft? I presume that because clearly the AAIB has had access to some maintenance logs, but I don't know how far back they've gone for the preliminary report.

Personally, I'm convinced that there was no electrical fault that caused both switch signals to be read as changed while the switches did not move; and will remain convinced unless the final report reveals evidence to the contrary. I hope that on second thought, you will be, too.

If the vast majority of flights have been made without anyone performing this particular action slip previously, without dismissing it, but giving it due consideration as a risk with potentially deadly consequences on every flight, is there a case for reviewing the procedure at the end of the flight, to cutoff one, count to 5 or 10, and cutoff the other, or have each crew member take care of "their" engine at that point?

I'm assuming that isn't an original idea, so how is it already addressed by Boeing, or the airlines, or pilots?

If you read the report, you'll see that the throttle was set to full power throughout, and the engines relit when set to RUN.

The. question about enforcing idle throttles before CUTOFF has been discussed voluminously on this thread.

Attention, Wall of Text incoming. Take appropriate precautions and fasten your seatbelts!

It is a bit difficult to not appear to use statistics in this fashion when trying to refute people using made up numbers and stories as argument.

If you had read the articles you quoted you might have realized that the basis for these "media reports" is a single individual who "heard from some Air India pilots". The supposed source wouldn't even have any way to actually know about the claimed information. Unless you want to elevate the Company Rumor Mill to hard evidence standard. This stands against:

Can we please stick to the actual facts, like za9ra22, and not spread baseless rumors that are self contradictory to begin with?

I find this a particularly concerning statement coming from someone who claims to be a pilot. Things like "Action Slip" and "Mental Load" should have been covered extensively in any CRM related education. If you think you are exempt from that kind of failure you are rejecting some very costly lessons learned over the last 50 years of accident investigation.

There have been many accidents where unindicated or even counter indicated action was taken by one or more pilots involved. As discussed in the first and second thread extensively many pilots could report incidents where they observed someone retracting flaps instead of gear. There have been major fatal accidents with pilots shutting down healthy engines instead of surging or burning ones. There's good reason the 787 has extensive takeoff configuration warnings, because we have had accidents and incidents with unsafe configurations taken to takeoff, beyond and sometimes even into a crash. Humans make mistakes. It is the goal of Safety Culture to prevent those mistakes from causing harm.

It was certainly mentioned. I'd not say it was discussed in any big way. Someone mentioned that for Embraer this is indeed the default, I haven't really found anything beyond that, despite considering it a worthwhile train of thought and possible recommendation as a result of this investigation.

This is a topic of actual research: https://www.pmhc.org/research
Currently 12.6% of pilots meet the medical threshold for depression, with a slight but below average difference between males (12.8%) and females (11.4%), with 4.1% of all pilots experiencing recent suicidal thoughts. https://ehjournal.biomedcentral.com/...940-016-0200-6

It should be noted that the utilized test (PHQ-9) is considered insufficient to assess suicide risk. Depending on scoring these values could be about average, or significantly below average. Based on their wording I would expect the latter, because their methodology does not specify severity.*1 Results of 0-4 points suggest no intervention necessary, 5-9 (classified as mild) simply suggest retaking the test after a few weeks. Research shows that for the general public Major Depressive Episodes have a prevalence of ~5-10%, with the prevalence of minor depression being less studied but significantly higher than major depression. There is also significant symptomatic overlap of mild depression with stress related conditions such as "Burnout" (if you know, please don't, this conversation is already complex enough without bringing that in). Considering the prevalence of stress in the industry I am actually surprised the numbers here are not higher. The lesser delta between males and females could be indicative of just such an issue, meaning that based on the data available the number of pilots actually suffering from depression could be less than even the comparably low number reported here. The actual suicide risk is usually orders of magnitude below even that but not easily covered in this data context due to the test used.

Cognitive impact is highly variable depending on the individual, actual symptoms and severity. It would be wrong to assess that 12.6% of pilots are a risk factor from this data. Quite the opposite, in fact. After the Germanwings crash the topic was discussed and has reached the awareness threshold for many. Mild cases usually require little to no intervention beyond raising awareness and helping the brain fix its chemistry through positive reinforcement. This can be as simple as taking PTO, reducing work hours, or focusing on social or physical activities. In the past 10 years these kinds of low impact measures have been made more readily available, most notably during the Covid-19 pandemic and the resulting turmoil.

Further political activity has lead to some positive action as well. I already mentioned the recent success of the Pilot Mental Health Campaign getting legislation through Congress for improvements of the outdated FAA guidelines on mental health in an earlier post. Similar efforts are underway globally, be that internal review within regulatory bodies, or political movements.

Keeping what I wrote previously in mind I would still caution against extrapolating your personal experiences too far. Having family in the field and having volunteered myself I can certainly relate, albeit with far fewer and less impactful personal experiences. The research is obviously lagging and we haven't really understood the impact of the Covid-19 pandemic generally, let alone in all its intricacies. There is indeed an observable global trend. Some correlation has been shown to climate anxiety, but other factors like the deteriorating condition of international relations as well as a global rise in movements against individual rights are obvious sources for this trend as well.
This is certainly a challenge for healthcare everywhere, but I do not consider the data available to be majorly applicable in the context of aviation over the already very current research closer to the industry and GA. The positive impact of what has been done and is being done is highly likely to outperform whatever global mechanism is at work here. It's certainly a very important field of study, but based on the data I would still consider the industry and regulators as a global whole to be on a positive path.

We can certainly discuss this topic further, but I would not currently see it as likely to be causal in this particular case.

Overall I am still not convinced we are looking at an individuals mental health crisis in this case. I have already detailed the massive differences to all known or suspected cases of pilot suicide at least twice. There is no evidence of mental health issues for the Captain or the FO. There is certainly a strong indication for a human factors cause to this accident. And as mentioned above I find the idea of improving the safety of the Fuel Cutoff Switches a worthwhile topic to discuss. No single action, and I see these two switches as a single action just as much as operating both thrust levers, should be able to cause a major accident. I find it perfectly reasonable to require the Throttle Levers be at idle for the Cutoff Switches to work, and in case of an incorrect setting some sort of alert would be appropriate.

*EDIT*
*1: I missed this in my original readthrough, the cutoff is sensibly set to 10, starting with moderate depression. I'd have to look into the classification scheme but from memory both mild and moderate depression fall into the same category as relevant for the following statements.

Driving a car is totally different than flying an aircraft. Pilots are trained over and over again for certain scenario's. The hands of a pilot during the liftoff have no reason at all to be anything near the fuel control switches.
When the fuel needs to be cut because of an engine failure there is a strict procedure before the switch is set to CUTOFF. Both pilots need to confirm the location (left or right) of the engine. No pilot will without consent switch off the fuel. However this is what happened.

If you look closely to the photo you will notice this is of a Boeing 737!
The Boeing 737 has the word IDLE on top of the switches, where the B787 has to word RUN on top.
Again read this https://feitoffake.wordpress.com/202...787-explained/

The fact is the switches on a Boeing 787 has a different part number than those of the B737. There is no replacement part for the B787.
The FAA SAIB does not mention to operators that the switches on a B787 needs to be changed.
The problem was on the Boeing 737 * only*

So your point is not valid. It is *impossible* these two switches were moved because of a malfunction of the locking mechanism.

I'll offer a guess as to why...later.
Why do you assume that improper installation?
How many times have you moved those switches, and the engines started without the switch being in the RUN position? (Either in the sim or in the aircraft).
Has anyone demonstrated to you something like
"watch this, Dani: if I pull the switch up and get it to hang on the little lock/cam, the engine will still start" ... in the sim or in the aircraft.
I'd be interested to read of your experiences with that switch and that non-standard positioning of it that you describe.

Beyond that, did you bother to look at the position of the fuel control switches that were in the preliminary report?
They were found in the RUN position. See page ten of the preliminary report.
Neither of them was cocked off, as in the picture of a misaligned switch from a 737 that you referred to.
On a 737.
The bulletin was Issued seven years ago. Why do you assume that people in the business sat on their hands for seven years?
Right. The facts are that the two fuel control switches were both found in the RUN position, not cocked to the side as your example from a 737 illustrates. Your entire line is unfortunately sunk by your attempt to challenge that fact.
You have established no basis for why you believe that the switches on this 787 were incorrectly installed, given that

1. the aircraft's crew (on the previous flight) successfully turned the fuel on and off on the flight from Delhi
2. the aircraft's flight deck crew successfully turned the fuel on, to RUN, before starting engines on the flight from Ahmedabad.

Your case is unsupported by the facts at hand.
As to post deletions: as with some of mine being deleted, we both seem to get involved in the running rodent machine despite any intentions to avoid it.

For DaveReidUK
Your post is, at best, disingenuous. (But thank you for posting an excerpt from the bulletin ).
The error was found on a 737, and the competent authority issued that alert having recognized that similar switches might have similar problems - they used the word potentia l - not because switches on all of those other models had been found to have that problem.
From your subsequent post:
I will also ask you whether or not you believe that airline companies the world over have sat on their hands for the last seven years, as regards fuel cutoff switches.
Given that this is the year 2025, (and the maintenance actions mentioned in the preliminary report) 1spotter's point on the "red herring" is a bit stronger than you allow. Please go back and read page 6 of the prelim report, top half.

Something else to think upon: how many 737s does Air India operate?
Does that have a relevance to this accident?
For the moment I don't think that it does, however, it might. The investigators have a variety of other rocks to turn over and see what crawls out from under them.
They may find evidence of various maintenance issues that have an impact on this accident.
As of today, though, such information has not been released (but I will offer you a guess that all of that is in the process of being collected and analyzed, even now, as a part of their investigation).

Full disclosure: I don't fly Boeings, I do not work for Boeing, I have no shares in Boeing stock, and I am still slightly pissed at Boeing for the MCAS screw up on the 737-MAX.

I really don't get it why you oppose to the thought it could happen on any Boeing aircraft. Since they are all very similar switches. Maybe it's even possible to interchange some of them. There are so many errors a maintenance organization can make. Fake parts?
What really frightens me is that you and others resolutely block even to think about the possibility. Because, let's be honest, the probability is not zero (and I would say nearer to 1 than to 0).

I have never moved such a switch, since I fly Airbus.
Let me ask you your question differently: How many times have you moved a faulty switch?
I know, that you and many others would immediatly identify such a bad switch and would render the aircraft as not airworthy. This is not the question. The question is: Has the Air India crew on that day identified the fault. And if yes, have they continued the flight preparation.
You don't need a suicide theory to explain such a simple course of action.

Dani

Got it. Argument from ignorance is noted.

But I'll offer you a concern I have for the position that you are taking.
You have unwittingly made an presumption that in the last two years, see the maintenance actions referred to in the Prelim Report...
... none of the pilots at Air India wrote up a faulty fuel control switch.
This is a switch that actual 787 and 777 pilots, who have have participated in this thread, have confirmed requires dual confirmation during operation, and one that has been highlighted as 'of interest' based on the bulletin we have all discussed.

But in Dani's world, the switch not working can be pressumed and the pilots never wrote it up because of {reasons}.

What do you have against all of the flight deck crews of Air India, that you believe that they would neglect to write up a fuel control switch that isn't working properly?

As an aside:

Have I ever moved the wrong switch? Yep. I think that reaching for a wrong switch with one's mind not quite on what one is doing is more likely than your "the switch wasn't working correctly" assertion / assumption, particularly given the position that they were found in at the crash site: latched in the RUN position).

When I was still flying, if a switch in the cockpit, or a fastener for a cowling, wasn't working correctly I wrote it up.
Whether or not the maintenance team fixed it immediately, or deferred the maintenance (based on the maintenance pubs), I wanted that on record so that (1) it would get fixed, and (2) to alert the next crew. I was taught that approach over 40 years ago.

Everything in the preliminary report suggest one of the pilots moved both switches seconds after the liftoff to the CUTOFF position.
If there was a 0,0001 percent chance the switches were faulty and could have moved because of gravity of an object hitting is, there would be a safety bulletin released to all B787 operators

There has not been such a bulletin.

The reason why the report does not mention which of the pilots ask " why did you cutoff ? " is unknown. We also do not know why it was written the switches ' transitioned' instead of ' moved' .
My guess it was either for political reasons or because of a possible criminal investigation.

For a pilot there is no reason to set both switches to cutoff without any reason. There was no engine fire. There was no discussion in the cockpit about using the switches.
Nothing. A mistake is extremely unlikely. There is no reason why the hands of a pilot needs to be near the switches. I do not believe in a brain fart.