Posts about: "Preliminary Report" [Posts: 277 Pages: 14]

Reuters, July 14 2025
Amid Air India probe, US FAA, Boeing notify fuel switch locks are safe, document, sources say

WASHINGTON/NEW DELHI/MONTREAL, July 13 (Reuters) - The U.S. Federal Aviation Administration and Boeing (BA.N), have privately issued notifications that the fuel switch locks on Boeing planes are safe, a document seen by Reuters showed and four sources with knowledge of the matter said.

The FAA's Continued Airworthiness Notification on July 11 came after a preliminary report into Air India's Boeing 787-8 crash, which killed 260 people last month, raised questions over engine fuel cutoff switches.

The FAA's notification to Civil Aviation Authorities, seen by Reuters, said: "although the fuel control switch design, including the locking feature, is similar on various Boeing airplane models, the FAA does not consider this issue to be an unsafe condition that would warrant an Airworthiness Directive on any Boeing airplane models, including the Model 787."

When asked for comment, the FAA said it did not have anything to add beyond the notification.

Boeing also referred to the FAA notification in a Multi-Operator-Message sent to the airlines in the past few days, which said the planemaker is not recommending any action, two of the sources with direct knowledge said.

When asked for comment, Boeing referred Reuters' questions to the FAA.

The preliminary investigation report into the crash by India's Aircraft Accident Investigation Bureau (AAIB), referred to a 2018 FAA advisory, which recommended, but did not mandate, operators of several Boeing models, including the 787, to inspect the locking feature of the fuel cutoff switches to ensure it could not be moved accidentally.

The report said Air India had said it had not carried out the FAA's suggested inspections as the FAA 2018 advisory was not a mandate. But it also said maintenance records showed that the throttle control module, which includes the fuel switches, was replaced in 2019 and 2023 on the plane involved in the crash.

The report noted "all applicable airworthiness directives and alert service bulletins were complied on the aircraft as well as engines."

ALPA India, which represents Indian pilots at the Montreal-based International Federation of Air Line Pilots\x92 Associations, in a statement on Saturday rejected the presumption of pilot error and called for a "fair, fact-based inquiry."

"The pilots body must now be made part of the probe, at least as observers," ALPA India President Sam Thomas told Reuters on Sunday.

ALPA India, in a letter posted on X, said the preliminary investigation report referred to the 2018 FAA advisory "concerning the fuel control switch gates, which indicates a potential equipment malfunction."

In the flights final moments, one pilot was heard on the cockpit voice recorder asking the other why he cut off the fuel. "The other pilot responded that he did not do so," the report said.

It said fuel switches had almost simultaneously flipped from run to cutoff just after takeoff. The report did not say how the switches could have flipped during the flight.

Two U.S. safety experts said on Saturday they backed ALPA India's request to be observers in the probe, but said the investigation report did not suggest a bias toward pilot error.

John Cox, a pilot and former ALPA U.S. representative, said AAIB's report seemed objective and fair.

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.

There is no way any pilot would be touching the stab trim switches right after rotation. It would go against every aspect of training. If the aircraft is flying ok you would never touch anything trim related until after cleanup and working the appropriate QRH or EICAS. I know some will bring up the Delta flight at LAX however that occurred above a 1000 feet and was in compliance with company policy and Boeing at the time where you got one free punch to reset the EEC.
It would also have been a data point on the FDR and in the preliminary report.

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.

This energy-based model illustrates Air India 171's flight profile from liftoff to impact. It uses the initial data point from FlightRadar24 of 184 kts G/S, 21 ft height, Google Earth for the crash location, and CCTV footage (originally posted on X) for timing.



A key observation is the calculated average ground speed of 150 knots from the initial point, just after takeoff, to the crash site, derived using the CCTV elapsed time. The model incorporates "best-guess" mid-points inferred from the CCTV footage, which help depict approximate indicated airspeeds consistent with the aircraft's energy state throughout the flight.



The analysis assumes zero thrust during the flight and an average Lift-to-Drag ratio of approximately 12. For this model, a takeoff mass of 210 tonnes and an estimated V2 of 160 knots were used.



Note: This analysis was conducted prior to the release of the AAIB preliminary report, and therefore does not account for the correct take off mass and the actual V2 of 162. The differences are small and as this is a rough best guess, it\x92s just a basic energy model to show the possible trade between speed and height. No account was made of an engine spooling up at the end of the flight. Visual review of the video suggests the thrust from any restarting engine must have been very low, as no significant yaw is discernible.

The captain reportedly took bereavement leave in 2022 after the death of his mother. The only other source for any claims about his medical history were made by a person named Mohan Ranganathan, a former Pilot who had until then publicly refuted claims of Pilot Suicide. He had supposedly "heard [that] from several Air India pilots". I have no reason to believe that random Air India Pilots would be privy to the reasons for any type of leave another pilot was taking. I have good reason to believe that a man like Captain Sabharwal would have been a great topic for baseless gossip.

So everything beyond the bereavement leave is based on statements by one of the many "experts" opining publicly for clout or money based on rumors from people who have no way of knowing what they are talking about. The list of baseless false statements by those experts is getting a bit long. If there was reason to believe Pilot Suicide we would expect Law Enforcement to be involved and the homes of both pilots to have been searched. Either this was done completely evading public notice, which I find hard to believe in such a high profile case, or it was not done at all. I find the latter option the more believable of the two.

There is no need to put any kind of emphasis on the "apparently" part. Obviously we are only looking in from the outside. But there is zero evidence for mental health issues and several indicators for this to not be the case. Taking time off to grief for a parent is a healthy and normal way to deal with a tragic life event like this. It shows that the Captain was both emotionally and financially stable enough to assess and prioritize his personal needs.

Again: Human Error is quite obviously a leading theory right now based on the preliminary report. Ascribing any kind of intent not based on factual information is not a good idea.

Quote:

Originally Posted by YYZjim

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?

I agree that the Preliminary Report will have been a very carefully chosen synopsis, but I don't think it precludes a system behaviour that might or might not even be categorised as either an electrical or mechanical malfunction, as such.

Consider that the Preliminary Report only references the CVR contents to indicate one crew querying why he (the other) cutoff, and the other denying it. Clearly very pertinent data to this investigation, so I'm not ruling out both of the crew being sincere, until I understand the aircraft system better.

If the cutoffs weren't triggered by the crew moving the switches, then the most likely thing was that both FADECs encountered a situation that invoked cutoff, practically at the same moment. That might suggest that the data from independent Run/Cutoff switches via independent poles that possibly route via a PIP or PIPs to various RDCs and in turn the CCS (which means these paths have a common mode) resulted in data to both FADECs "failing" in a critical manner simultaneously.

The only CCS vulnerability I'm aware of is what happens if the CCS is kept powered for 51 days, shortly after which, the Time Manager data integrity for ARINC 664 messages is compromised, possibly only considered critical n conjunction with a CDN Switch failure. AD 2020-06-14 therefore requires a maintenance action of cycling the CCS power at least once every 25 days.

Two such omitted, or incorrectly executed maintenance actions in a row would have to happen for that known issue to be relevant. Perhaps there is some other input in the CCS system that influences both lanes of data to the FADECs for the Cutoff to be triggered, but I'm not aware of such.

If the data to both FADECs became good again around the same time (perhaps no longer Stale Data, or an alternative source selected, or other mechanism), and given the unavailability of APU power at this point, might Engine 1 restart be initiated first, and might Engine 2 restart be triggered 4 seconds later by the FADECs? Is that possible without the crew cycling the switches?

Regarding AD 2020-06-14, which was approved quickly, Boeing subsequently offered revised wording, which changed "may" to "will", see FAA Docket 2020-0205-0004, but as it did not alter the maintenance action, it was not adopted. A fuller description of possible consequences was in FAA Docket 2020-0205-0001_content, but it was quite wide ranging, and didn't attempt to characterise specific aircraft systems behaviour.

For anyone wanting more information on the CCS, in the context of that Airworthiness Directive, I recommend reading A Reverse Engineer’s Perspective on the Boeing 787 ‘51 days’ Airworthiness Directive at IOActive.

As a non-professional pilot, please accept that my knowledge of much beyond the CCS is patchy, but I welcome this scenario being critiqued.

Thank you for your time, and I'm just donning my hard hat and flack jacket.

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.

To quote the preliminary report for completions sake:
The reverser levers are made from Aluminium as far as I know? So anything capable of bending them would certainly be capable of displacing the Thrust Levers.

One of the initially discussed variants was inadvertent operation of the Fuel Cutoff Switches instead of putting up the landing gear. There was some pushback against that idea based on the position of the landing gear. As far as I recall the observed position of the landing gear was ultimately deemed to be caused by loss of hydraulics, and not as caused by interruption of the raising operation, making it fully compatible with the preliminary report. It's curious that the report does not mention the positive rate and gear up call out, either for its absence or it being made. It does note that the landing gear lever was in the down position, which isn't unusual for a severe event just after V2 but also in line with the theory.

With what we know now from the preliminary report that option seems to be a good candidate as the source of initiation for an action slip. Both the PF instead of calling Gear Up Action Slipping and operating the Cutoff Switches, or the PM instead of calling Positive Rate doing so would fit that scenario and timeline.

The authors of the preliminary report would surely have known that the report as drafted would raise strong suspicions of an intentional act by one of the pilots to shut off the fuel switches. If the investigators had evidence that would indicate that it was not (or may not have been) a deliberate act (from for example the rest of the verbal exchanges between the pilots) then surely they would have included such information in the report in order to avoid such a conclusion from being drawn by the reading public. This suggests that there is no such evidence.

I first didn't understand his answer as well (it was my question). In the meantime I know more about the logic: The fuel shutoff valves are not operated by the FADEC. The switches are wired directly to latching relays that drive the (latching) fuel valves. Using an additional pole of that switch the FADEC just gets the information that the switch was operated (and of course the current position). The FADEC can then e.g. execute the engine restart sequence if required.

Or simply not have paraphrased that particular exchange in the preliminary report.

More likely as with investigation reporting, they\x92re simply calling balls and strikes and really aren\x92t concerned about the conclusions readers make.

Absolutely true. I can imagine that this report is a compromise among the investigators and was issued after representatives of Boeing and the USA, were happy that they would be able to say that there were no technical issues that caused the crash and the Indian side of the investigation team that is not ready (if they will ever be...) to acknowledge that the switching off was an intentional, deliberate action.

If crew action is the root cause of this, then the above may be the "best" we, as a pilot community, can hope for.

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.

After all the analysis on PPRuNE, fuel switch failure (well, dual switch failure, at practically the same time) seems so unlikely it's no longer worthy of consideration. However, I'm still open to the idea of a failure elsewhere that may have signalled the fuel switches had transistioned from Run to Cutoff wthout physical movement of either switch. Why? Firstly, because of this (taken from the preliminary report)



The STAB cutout switches are located next to the Fuel cutoff switches. What did Air India’s on duty AME do as part of their troubleshooting? Were panels removed to gain access to the rear of the switches and wiring? What about wiring and data connections elsewhere? What may have been disconnected/disturbed as part of this process? Do the STAB cutout switches and Fuel cutoff switches share any connectors that could have been inadvertantly cross-connected? Etc. It would not be the first time that an engineer had innocently done something that later caused an accident. And I haven't read anything about possible nefarious action by a (disgruntled?) engineer - but I've seen lots of accusations directed at the pilot(s)...

Secondly, the preliminary report's version of (part of) the conversation in the cockpit -
Until proven beyond reasonable doubt I'm chosing to take the cockpit conversation at face value, because I really don't want to believe any of the following scenarios:
A) one of the pilots lied
B) one of the pilots attempted to deflect blame onto the other pilot for the benefit of the CVR
C) One of the pilots unknowingly operated the fuel cutoff switches.
D) One of the pilots deliberately operated the fuel cutoff switches.

It is all too easy to blame one of the pilots when in reality no one outside of the official investigation may yet know what most likely happened.

Since the preliminary report neglected including when the RAT deployment occurred, I've tried to estimate it based on the picture they did include:




Baro altitude should be around 150ft; using the public cctv video, I estimate this picture was taken between 4-7 seconds after rotation. A wide range, but that was the best estimate I could come up with. Maybe someone else could narrow it down further.