Page Links: First Previous 45 46 47 48 49 50 51 52 53 54 55 56 Next Last Index Page
| Lonewolf_50
February 03, 2026, 01:26:00 GMT permalink Post: 12031379 |
Now there is a separate avherald-article for this incident:
https://avherald.com/h?article=5342238e&opt=0 The foundation stated when asked why the aircraft departed nonetheless: "The issue is, there is no guidance." ... unbelievable Or, as Lifer01 points out, replace the next higher assembly (the module). Last edited by Lonewolf_50; 3rd February 2026 at 15:24 . Subjects
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| nikplane
February 03, 2026, 05:03:00 GMT permalink Post: 12031405 |
B787 Remember the past check:India's DGCA - Jul 14th 2025.
-
B787 Remember the past check: India 's DGCA - Jul 14th 2025. On Jul 14th 2025: India's DGCA instructed airlines to check the fuel control switches (Run-Cutoff) on the B787 and B737 aircraft as used by Air India Group, Indigo and Spicejet for possible disengagement of the fuel control switch locking feature according to the SAIB released by the FAA on Dec 17th 2018 . The checks have to be completed by Jul 21 2025 . Last edited by nikplane; 3rd February 2026 at 05:48 . Subjects
DGCA
FAA
Fuel (All)
Fuel Cutoff Switches
Special Airworthiness Information Bulletin
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| DTA
February 03, 2026, 11:36:00 GMT permalink Post: 12031533 |
The BBC have this story now.
https://www.bbc.co.uk/news/articles/c8e5zwndddyo
Air India has grounded a Boeing 787-8 Dreamliner jet after one of its pilots reported a possible defect in the aircraft's fuel control switch.
The airline said in a statement on Monday that it had informed India's aviation regulator about the issue and that it was getting the pilot's concerns checked on a "priority basis". "We are in contact with Air India and are supporting their review of this matter," a Boeing spokesperson said in response to an email. On Tuesday, Reuters news agency reported, external that Air India had begun re-checking the fuel switches on its Boeing Dreamliner aircraft following the incident flagged by the pilot. Subjects
BBC
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Fursty Ferret
February 03, 2026, 13:38:00 GMT permalink Post: 12031598 |
This is - in my opinion, I must stress - an incredibly clumsy move by an Air India pilot. I think the impartiality of the investigation was always dubious, and now even more so.
I can quite believe a fuel control switch not latching in position, because I've seen it happen myself when going from run to cut-off where someone let it sit on top of the raised lip between positions instead of deliberately moving it to cut-off. I can just about conceive of a case where someone did this on engine start and the switch flicked to cut-off with the thumping of the nose wheel over a rough runway. Do I believe that it could happen simultaneously to both switches? No. On top of that, when did they discover this? Were they flipping the switch during engine start? Did they abort the start and experiment with the switch? Why didn't they get engineering assistance? This is just spectacularly dodgy decision making. Subjects
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| DTA
February 03, 2026, 13:55:00 GMT permalink Post: 12031609 |
This is - in my opinion, I must stress - an incredibly clumsy move by an Air India pilot. I think the impartiality of the investigation was always dubious, and now even more so.
I can just about conceive of a case where someone did this on engine start and the switch flicked to cut-off with the thumping of the nose wheel over a rough runway. Do I believe that it could happen simultaneously to both switches? No. Subjects
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Musician
February 03, 2026, 14:02:00 GMT permalink Post: 12031615 |
The document from the tweet, in full:
https://www.pib.gov.in/PressReleaseP...6®=3&lang=1
Ministry of Civil Aviation
Rejoinder on News Item relating to purported malfunction of Fuel Cut Off Switch on M/s Air India Boeing B787-8 aircraft VT-ANX
Posted On: 03 FEB 2026 5:27PM by PIB Delhi
.
On 01.02.2026, Air India B787-8 aircraft VT-ANX operated flight AI 132 (London- Bangalore). During engine start in London, on two occasions crew observed that the fuel control switch did not remain positively latched in the “RUN” position when light vertical pressure was applied. On the third attempt, the switch latched correctly in “RUN” and subsequently remained stable. Before continuing with the rest of procedure, a physical verification was performed by the crew to confirm that the switch was fully and positively latched in the “RUN” position. No abnormal engine parameters, cautions, warnings, or related system messages were observed during engine start or at any time thereafter. The operating crew member was briefed on the observation, unnecessary contact with the switch was avoided, and engine indications and alerting systems were closely monitored by the crew for the remainder of the flight. The flight was completed without incident.
After landing at Bangalore, crew reported the defect in the PDR. Air India referred the matter to M/s Boeing for further guidance. Based on the M/s Boeing recommended checks to establish the serviceability of fuel control switch, M/s Air India engineering observed that:
“Both left and right switches were checked and found satisfactory, with the locking tooth/pawl fully seated and not slipping from RUN to CUTOFF. When full force was applied parallel to the base plate, the switch remained secure. However, applying external force in an incorrect direction caused the switch to move easily from RUN to CUTOFF, due to the angular base plate allowing slip when pressed improperly with finger or thumb.”
In addition, based on Boeing’s communication, the pull-to-unlock force was checked on the fuel control switch using the recommended procedure on the involved fuel cut off switch, the fuel control unit to be installed and fuel cut off switch of another aircraft. In all cases the pull-to-unlock force was found within limits. These inspections were carried out in the presence of DGCA officers.
The video currently circulating on social media was analysed in light of Boeing recommended procedures, and it was observed that the procedure demonstrated in the video being circulated is incorrect.
The airline is being advised to circulate the Boeing recommended procedure for the operation of Fuel CUT OFF switch to its crew members.
Subjects
DGCA
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Parameters
RUN/CUTOFF
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Pilot DAR
February 03, 2026, 14:25:00 GMT permalink Post: 12031636 |
However, applying external force in an incorrect direction caused the switch to move easily from RUN to CUTOFF............
..........due to the angular base plate allowing slip when pressed improperly with finger or thumb.”
On the third attempt, the switch latched correctly in “RUN” and subsequently remained stable.
Though this discussion being about the RUN/CUTOFF switch(s) of a 787 being accused of improper operation, does this really relate to the Air India 171 crash? The reported information has already stated that both switches were selected from RUN to CUTOFF within a second, and then back to RUN, with a pilot remark about that action. It is a statistical infinity that on 171 both switches would fail into the cutoff position by themselves within a second, and there not be a pilot remark about that in the CVR, when there was a remark "Why did you do that?" associated with the switches. I have moved a lot of switches and other controls in my flying career. In each case, I made that action with the intent that doing so would cause the desired action of a system. Moving the control itself was a means to an end. So, in moving the control, I determined that the ultimate objective was achieved. If there was a "feel" or locking system associated with the motion of the switch/control, then I would assess that too - was it working as expected? Like a flap or landing gear selector, I don't just push it toward the other direction, and hope that it pops into the desired position, I actually move the control the whole way, and confirm by feel/sight/locking device, that it is where I intend it to be, and will stay. Let's not forget that very basic expectation of piloting! Yes, there is the phrase "throw the switch", but that is for Igor. We pilots will move the switch the whole way, and assure that it got where it was going and is going to stay! Both of these topics relate to the switch(es) in the 787, but I think that the similarity ends there. Subjects
CVR
Fuel (All)
Fuel Cutoff Switches
RUN/CUTOFF
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Ver5pen
February 03, 2026, 14:52:00 GMT permalink Post: 12031660 |
We already have several threads on AI171 issues (at least one of them in
Tech Log
), so moving this discussion to its own thread seems unproblematic.
The significance of this new finding is that it makes accidental movement more likely. We already know about the incident where a sun visor fell and moved the switch. We are learning now that the mechanism of "pull up, then move the switch" can be circumvented, and that the switch can be moved by a single application of force. It appears that the engineers were able to reproduce this behaviour, so it's no longer just that crew's word. So while on VT-ANB both switches moved at the same time, and that is unlikely to happen by itself, it now appears possible that an external force such as a loose object or an inadvertant pilot motion could have moved both switches. At least, this requires further study to narrow down the conditions for it, and to check whether these conditions were present on the accident flight. all of the noise about these switches being foolproof and above suspicion hence it could only have been deliberate action yet many airlines have suffered inadvertent engine shutdowns because of accidental manipulation of fuel cut off switches/engine masters in and these specific switches on the identical fleet in the same airline, it\x92s certainly a noteworthy revelation dismissing this as professional crews trying to cover up for their colleagues or some other highly absurd slanderous accusation I would\x92ve hoped was beneath PPRUNE, but of course only Indians/foreigners are to be doubted, everyone else are professionals who only ever act with integrity. We\x92ve never seen western/American OEMs or regulators falling short on this absolutely not. Subjects
AI171
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Flightmech
February 03, 2026, 17:39:00 GMT permalink Post: 12031737 |
This is nothing but a timed and very poor attempt at a diversion from reality. Oh look, we found a fuel cutoff switch problem on another one of our fleet (but flew on with it anyway).
Subjects
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Pilot DAR
February 03, 2026, 17:57:00 GMT permalink Post: 12031742 |
Oh look, we found a fuel cutoff switch problem on another one of our fleet
Preceding a "however" This was reported:
“Both left and right switches were checked and found satisfactory, with the locking tooth/pawl fully seated and not slipping from RUN to CUTOFF. When full force was applied parallel to the base plate, the switch remained secure.
Subjects
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
RUN/CUTOFF
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Musician
February 03, 2026, 18:53:00 GMT permalink Post: 12031774 |
I read a report of a problem. I'm not sure that I actually see a report that there truly
was
a problem.
Preceding a "however" This was reported: If a "however" is written after that statement, it is either meaningless and to be ignored, or it has the effect of negating the statement. There is no "partly airworthy" for these switches. It can't be both statements. Thus, my doubt about the credibility/applicability of this whole situation in the context of the 171 crash, subject to these two statements being reconciled with each other. I imagine one way for this to be true would be if the lever has some wiggle room, such that the teeth on it can move sideways past the teeth on the base, and then stick in that position where the lever is up and the flanks of the teeth are still touching. In that position, you could flip the switch back off without overcoming the detent. But if you operate the switch properly, with no sideways force, and seat the lever correctly in the ON position, then it'd be secure. That fits with the part of the press release about telling the pilots how to operate these switches properly. Obviously I have no idea if this is true. I just want to give an example of how that switch might be operated one way to be unsafe, and another way to be safe. I'd really want to see Boeing's take on this, and not a third-hand press release that went from Boeing to Air India engineering to ??? to the ministry. It may say something impossible that differs from the possible thing the engineers actually found. Subjects
Fuel (All)
Fuel Cutoff Switches
Fuel Cutoff Switches (detent)
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Abbas Ibn Firnas
February 03, 2026, 21:12:00 GMT permalink Post: 12031844 |
This should never be allowed to happen again. As things stand it's entirely possible it could. I would hope the final report will recommend a re-think as to how this critical system could be improved to prevent miss use or failure.
Any mention of modifications have received pushback because operators cite how long Boeing have been doing it this way without any serious issues. I feel that standpoint incredibly ill-advised given that the situation could be improved to negate single point failure or deliberate action, or at least determine which had occurred. Previous discussions on here relating to either relocating or guarding the switches has been dismissed by most as unnecessary, which I can understand, as it would probably add little in the way of increased safety. I'm no designer of aircraft systems, but reading this continued discussion about springs, detents latching wiggling and misplaced pressure, I'm astonished this whole incident exclusively involves only one mundane yet important component. My point really is 1 engine cut-off should not be possible at 100ft elevation. 2 A single switch malfunction should not shut down engine(s) Subjects
Fuel (All)
Fuel Cutoff Switches
Fuel Cutoff Switches (detent)
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| MechEngr
February 03, 2026, 21:24:00 GMT permalink Post: 12031849 |
I imagine one way for this to be true would be if the lever has some wiggle room, such that the teeth on it can move sideways past the teeth on the base, and then stick in that position where the lever is up and the flanks of the teeth are still touching. In that position, you could flip the switch back off without overcoming the detent. But if you operate the switch properly, with no sideways force, and seat the lever correctly in the ON position, then it'd be secure. That fits with the part of the press release about telling the pilots how to operate these switches properly.
Clearly the design of the latch requires that it move from one position to another position with some applied forces. Absent some clarification of what the pilot(s) did or observed, their statement matches the way the switch is supposed to function. " However, applying external force in an incorrect direction caused the switch to move easily from RUN to CUTOFF, due to the angular base plate allowing slip when pressed improperly with finger or thumb.\x94 The problematic part of the statement is that there is nothing that says what they think the incorrect direction is. But, if one wants it to move it must be pushed in a direction that is incorrect for it to remain locked in position. It is almost certain that if one pushes towards the opposite position from the current locked one and, at the same time uses the friction from that push, one can pull the plunger up and disengage the lock. Is that what they meant by "incorrect direction"? Who, besides them, know what they meant? Subjects
Fuel (All)
Fuel Cutoff Switches
Fuel Cutoff Switches (detent)
RUN/CUTOFF
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| ignorantAndroid
February 03, 2026, 22:12:00 GMT permalink Post: 12031878 |
For reference, Boeing does not provide a procedure to replace the cut-off switches. If there is an issue with a fuel cut-off switch, the whole thrust control module is to be replaced, ie. the throttle levers and cut-off switches are in one module.
I believe this has been the case since before the AI accident. Subjects
Fuel (All)
Fuel Cutoff
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Fursty Ferret
February 03, 2026, 23:14:00 GMT permalink Post: 12031908 |
2. This is taken into consideration at the design stage and isn't an issue. Subjects
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| TURIN
February 04, 2026, 00:52:00 GMT permalink Post: 12031928 |
Is there any evidence of the cut off switch failing AND shutting the engine down? Subjects
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Chernobyl
February 04, 2026, 07:06:00 GMT permalink Post: 12032008 |
Subjects
Engine Failure (All)
Engine Shutdown
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| FullWings
February 04, 2026, 07:41:00 GMT permalink Post: 12032024 |
It could possibly be an interesting failure mode of the FCSs but a) it still appears to require significant (deliberate) force to make it happen and b) on the accident flight both switches go to cutoff and are left there for some considerable time before being put back to run despite the crew being aware of their unusual position for the phase of flight (CVR). Chances of this happening without pilot input infinitesimal?
Subjects
CVR
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| DaveReidUK
February 04, 2026, 09:26:00 GMT permalink Post: 12032065 |
The problem with your stated concern is how do you prevent it? Simple, you say: interlock it with the thrust levers and/or radio alt and/or baro alt in some combination to ensure you can ONLY switch to cutoff if not below 400' ft or at takeoff thrust. But what happens if this new logic fails in a novel way in the future preventing an engine shutdown when it really IS needed? Any new complexity adds potential unintended consequences and hence risks. Is the cure worse than the disease? Right now, the switch design is entirely consistent with Boeing standard practice: flight crew actions are the final say.
We really don't need to read any more headlines that feature "Boeing" and "unintended consequences". Subjects
Engine Failure (All)
Engine Shutdown
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
| Musician
February 04, 2026, 11:16:00 GMT permalink Post: 12032148 |
The problem with your stated concern is how do you prevent it? Simple, you say: interlock it with the thrust levers and/or radio alt and/or baro alt in some combination to ensure you can ONLY switch to cutoff if not below 400' ft or at takeoff thrust. But what happens if this new logic fails in a novel way in the future preventing an engine shutdown when it really IS needed? Any new complexity adds potential unintended consequences and hence risks. Is the cure worse than the disease? Right now, the switch design is entirely consistent with Boeing standard practice: flight crew actions are the final say.
Obviously Boeing can't easily change "standard practice", especially if they want to keep training costs for pilots switching types low, but that doesn't mean it's not a good idea in general. If this logic fails "when it is really needed", the pilot can still pull the fire handle. Or the engine won't start, but then they'd still be sitting at the airport. But I don't think the aircraft that already have this have had issues? Subjects
Engine Failure (All)
Engine Shutdown
Fuel (All)
Fuel Cutoff Switches
Reply to this quoting this original post. You need to be logged in. Not available on closed threads. |
Page Links: First Previous 45 46 47 48 49 50 51 52 53 54 55 56 Next Last Index Page