July 01, 2025, 07:45:00 GMT
permalink Post: 11914074
I've heard of conspiracy theories, but thinking that Boeing and the FAA have allowed the 787 to be certified with a non-compliant fuel system operation is going a bit far. And what about EASA? Plenty of European operators of 787s; EASA must agree it's compliant. "A320/737 does this" is totally irrelevant.
July 01, 2025, 08:26:00 GMT
permalink Post: 11914098
I've heard of conspiracy theories, but thinking that Boeing and the FAA have allowed the 787 to be certified with a non-compliant fuel system operation is going a bit far. And what about EASA? Plenty of European operators of 787s; EASA must agree it's compliant. "A320/737 does this" is totally irrelevant.
EASA 787-8 TC
The FAR/CS 25 doesn\x92t seem to require fuel from separate tanks during takeoff.
July 11, 2025, 20:40:00 GMT
permalink Post: 11919771
- fuel cut offs were found in the RUN position
- on take off roll both engines lost power as the fuel cut offs went from RUN to cutoff
- CVR recorded one pilot asking why they had gone to CUTOFF
- within 10 seconds the fuel cutoff was moved back to RUN
-RAT was deployed, APU had begun auto start
- 32 seconds after Vr the MAYDAY was called
This should also dispel a lot of the comments about AAIB-India, Indian culture in general and general competence. For a preliminary report this is far more thorough and extensive than what would normally be expected and they\x92ve kept Boeing, GE, FAA and investigators from US, UK, Canada and Portugal in the loop from the start
They have also clarified why it took so long to do the EAFR download- because of the extensive damage they had to source specialist equipment from the NTSB that only arrived on the 23rd of June (they downloaded on the 24th) so all that talk of a \x91coverup\x92 is pretty embarrassing now
of course the big question is why/how those switches were commanded into cutoff in the first place the exact sequence at Vr is the most critical, there hasn\x92t been much scrutiny at all that I can see in the Indian/international media of the personal
background of the flight deck crew which has happened in other suspected pilot initiated disasters in the past, I guess this is an avenue investigators will have been doing themselves
- on take off roll both engines lost power as the fuel cut offs went from RUN to cutoff
- CVR recorded one pilot asking why they had gone to CUTOFF
- within 10 seconds the fuel cutoff was moved back to RUN
-RAT was deployed, APU had begun auto start
- 32 seconds after Vr the MAYDAY was called
This should also dispel a lot of the comments about AAIB-India, Indian culture in general and general competence. For a preliminary report this is far more thorough and extensive than what would normally be expected and they\x92ve kept Boeing, GE, FAA and investigators from US, UK, Canada and Portugal in the loop from the start
They have also clarified why it took so long to do the EAFR download- because of the extensive damage they had to source specialist equipment from the NTSB that only arrived on the 23rd of June (they downloaded on the 24th) so all that talk of a \x91coverup\x92 is pretty embarrassing now
of course the big question is why/how those switches were commanded into cutoff in the first place the exact sequence at Vr is the most critical, there hasn\x92t been much scrutiny at all that I can see in the Indian/international media of the personal
background of the flight deck crew which has happened in other suspected pilot initiated disasters in the past, I guess this is an avenue investigators will have been doing themselves
July 11, 2025, 20:47:00 GMT
permalink Post: 11919775
FAA issued an SAIB in 2018 about these fuel control switches being installed without the locking feature engaged\x97Air India didn\x92t act on it (not mandatory).
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
July 11, 2025, 20:53:00 GMT
permalink Post: 11919779
FAA issued an SAIB in 2018 about these fuel control switches being installed without the locking feature engaged\x97Air India didn\x92t act on it (not mandatory).
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
then again this isn\x92t all pointing at the pilots which is interesting
July 11, 2025, 21:00:00 GMT
permalink Post: 11919790
FAA issued an SAIB in 2018 about these fuel control switches being installed without the locking feature engaged\x97Air India didn\x92t act on it (not mandatory).
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
No evidence of birdstrike, fire, or mechanical failure. Both engines had good health data. The only obvious explanation at this stage is an inadvertent dual shutdown by crew,
Last edited by Diff Tail Shim; 11th July 2025 at 21:18 .
July 12, 2025, 02:55:00 GMT
permalink Post: 11920123
I assume the 10 second pause is based on how long it took the two 767 event pilots to realize their error and return the switches to RUN.
July 12, 2025, 03:34:00 GMT
permalink Post: 11920144
Unless defective. I only encountered one in a 30 plus year career where my Captain shutdown at block in and did not like the feel and checked that the detent was worn. Wrote it up. But Boeing installed some that did not have a detent and the FAA issued a SAIB, referenced in the Air India mishap report, to check for these switches because they could inadvertently be positioned to off. Whether they meant human or other inadvertent action was not clear.
July 12, 2025, 09:14:00 GMT
permalink Post: 11920399
When I was a young F/O, some of the captains I flew with had the (annoying) habit of resting their hands just behind the thrust levers on their PM (PNF) sectors to 'be ready' to reject the takeoff. This would put the hands in the vicinity of the Fuel Cutoffs, which would, in turn, increase the chances of an unintended action on these switches. Is this a possibility, or am I way off?
Last edited by Senior Pilot; 12th July 2025 at 09:25 . Reason: Quote
July 12, 2025, 21:15:00 GMT
permalink Post: 11920836
Check your switches
At this stage of the investigation, where the preliminary report is limited to
facts and evidence
, there may be insufficient knowledge to warrant urgent safety action.
However, some national regulators might choose to reiterate the FAA SAIB: NM-18-33, requiring that all switches must be checked i.e. not optional.
Additionally, and independently, pilots might check the switches preflight (nice to know): - note the range of different types of aircraft and variants which could be affected - fleet size, number of switches exposed to the condition.
Regulators might also enquire of the FAA how many 'non locking' switches were identified by the SAIB - what was reported; and 'non FAA' operators recheck their inspection results and action taken.
… and how many operators did not check.
If errant switches were identified, then was the original safety assessment reconsidered (FAA/Boeing), if so what arguments were made against inadvertent simultaneous operation.
https://static-gi.asianetnews.com/co...nm-18-33-1.pdf
However, some national regulators might choose to reiterate the FAA SAIB: NM-18-33, requiring that all switches must be checked i.e. not optional.
Additionally, and independently, pilots might check the switches preflight (nice to know): - note the range of different types of aircraft and variants which could be affected - fleet size, number of switches exposed to the condition.
Regulators might also enquire of the FAA how many 'non locking' switches were identified by the SAIB - what was reported; and 'non FAA' operators recheck their inspection results and action taken.
… and how many operators did not check.
If errant switches were identified, then was the original safety assessment reconsidered (FAA/Boeing), if so what arguments were made against inadvertent simultaneous operation.
https://static-gi.asianetnews.com/co...nm-18-33-1.pdf
Last edited by Pilot DAR; 12th July 2025 at 21:19 . Reason: typo
July 12, 2025, 21:17:00 GMT
permalink Post: 11920838
I believe the *inspection* was not conducted, and whether there was a fault with the configuration of the switch on the accident aircraft is not answered in the report.
If pilots were able to move this aircraft's cutoff toggles without lifting them, it seems that might have been reported at some point during its service. But then again, maybe the difference in operation between a correctly configured switch (requires lift to toggle) and incorrectly configured one (does not require lift, but lifting it still works as expected) is not noticeable.
I'd be curious to know if India Air has (finally) inspected these switches in their fleet since the accident.
July 13, 2025, 00:16:00 GMT
permalink Post: 11920954
The throttle quadrant was also replaced.
. The scrutiny of maintenance records
revealed that the throttle control module was replaced on VT-ANB in 2019 and 2023.
However, the reason for the replacement was not linked to the fuel control switch. There has
been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB.
revealed that the throttle control module was replaced on VT-ANB in 2019 and 2023.
However, the reason for the replacement was not linked to the fuel control switch. There has
been no defect reported pertaining to the fuel control switch since 2023 on VT-ANB.
July 13, 2025, 17:40:00 GMT
permalink Post: 11921477
Hi,
I have a couple of questions. Forgive me for being late into this thread if any of them is already discussed:
1) I just read this in a Boeing manual:
2) Looking at the incident timeline, one of the pilots takes corrective action to reswitch to RUN position 10 seconds after maximum air speed is reached and 5 seconds after RAT is deployed. Is this normal?
It's not clear however that whether their conversation is after or before the RAT is deployed.
(No visual or auditory cues in the cockpit for a critical fuel switch action? Not hearing the engines shutting down?)
3) The same pilot that turns on Engine 1's fuel switch, turns on Engine 2's switch 4 whole seconds later. Why not consecutively, right one after the other, just like they were turned off one second apart?
If only he had done so the second engine might have recovered in time as well.
4) This aircraft's TCM has been replaced in 2019 and 2023, not related to a fuel switch issue. And there had been no fuel switch defect reports since 2023. One begs to ask if there had been a fuel switch defect report back in 2023 and what was the nature of it?
Are TCM's replaced as a whole, including the switches, twice? If so, why wouldn't they install a TCM version at least in 2023 with redesigned switches (w/ enhanced locking mechanism) mentioned in the FAA SAIB? Have they installed old/used TCM's manufactured prior to 2018 SAIB?
Please note that the RH and LH GE engines of the aircraft were only installed in March 2025 and May 2025 respectively, but they were used and dating from 2013 and 2012. Is this normal for a 12 year old Boeing aircraft to change so many mission critical components?
Electronic parts somehow, but how durable are those GE engines?
Thanks,
C.A.
I have a couple of questions. Forgive me for being late into this thread if any of them is already discussed:
1) I just read this in a Boeing manual:
The fuel control switches send signals to open or close fuel valves to operate or shutdown the engines.
- They send signals to the remote data concentrators (RDC) and the spar valve start switch relays.
- The spar valve start switch relays use these signals to control the spar valve and the high pressure shut off valve (HPSOV) in the fuel metering unit (FMU).
- The RDCs send the signals to the common data network (CDN) and then to the electronic engine control (EEC) to operate the FMU fuel valves (FMV and HPSOV).
The fuel control switches have 2 positions:
- RUN
- CUTOFF.
You must pull the switch out of a detent to select a position.
There seems to be RDC's (remote data concentrators) and CDN (common data network) between those fuel switches and the fuel valves. Is there any possibility that there may have been an electronic control module or sensor fault to generate such a signal rather than mechanical switch movements?
- They send signals to the remote data concentrators (RDC) and the spar valve start switch relays.
- The spar valve start switch relays use these signals to control the spar valve and the high pressure shut off valve (HPSOV) in the fuel metering unit (FMU).
- The RDCs send the signals to the common data network (CDN) and then to the electronic engine control (EEC) to operate the FMU fuel valves (FMV and HPSOV).
The fuel control switches have 2 positions:
- RUN
- CUTOFF.
You must pull the switch out of a detent to select a position.
2) Looking at the incident timeline, one of the pilots takes corrective action to reswitch to RUN position 10 seconds after maximum air speed is reached and 5 seconds after RAT is deployed. Is this normal?
It's not clear however that whether their conversation is after or before the RAT is deployed.
(No visual or auditory cues in the cockpit for a critical fuel switch action? Not hearing the engines shutting down?)
3) The same pilot that turns on Engine 1's fuel switch, turns on Engine 2's switch 4 whole seconds later. Why not consecutively, right one after the other, just like they were turned off one second apart?
If only he had done so the second engine might have recovered in time as well.
4) This aircraft's TCM has been replaced in 2019 and 2023, not related to a fuel switch issue. And there had been no fuel switch defect reports since 2023. One begs to ask if there had been a fuel switch defect report back in 2023 and what was the nature of it?
Are TCM's replaced as a whole, including the switches, twice? If so, why wouldn't they install a TCM version at least in 2023 with redesigned switches (w/ enhanced locking mechanism) mentioned in the FAA SAIB? Have they installed old/used TCM's manufactured prior to 2018 SAIB?
Please note that the RH and LH GE engines of the aircraft were only installed in March 2025 and May 2025 respectively, but they were used and dating from 2013 and 2012. Is this normal for a 12 year old Boeing aircraft to change so many mission critical components?
Electronic parts somehow, but how durable are those GE engines?
Thanks,
C.A.
When reading any of the data when it comes out, pay some attention to the sampling rate of the data being provided, it is quite possible to make erroneous assumptions where that is not taken into consideration. The data buses used to get data from the aircraft system to the recorder, and the recorders themselves use sequential sentences, and varyious rates.
IMHO.
July 13, 2025, 21:34:00 GMT
permalink Post: 11921685
SAIB NM-18-33 Interpretation
Reading
SAIB NM-18-33
My Interpretation/reading:
Some 737 Operators reported incorrect/broken locking features on cutoff switches - PN 766AT613-3D
If you have PN 766AT61 3 -3D installed - Replace it with 766AT61 4 -3D, which includes an improved locking feature.
The other Aircraft listed - have switches with similar design. In the case of the B787, switch PN 4TL837-3D. Check those AC to ensure locking is OK, and if you do happen to find something odd, let us (the FAA) know.
No-one, has ever found anything wrong with any of those other switches, or there would be AD's.
Thus there is not a problem with 787 Fuel Switch locking features.
My Interpretation/reading:
Some 737 Operators reported incorrect/broken locking features on cutoff switches - PN 766AT613-3D
If you have PN 766AT61 3 -3D installed - Replace it with 766AT61 4 -3D, which includes an improved locking feature.
The other Aircraft listed - have switches with similar design. In the case of the B787, switch PN 4TL837-3D. Check those AC to ensure locking is OK, and if you do happen to find something odd, let us (the FAA) know.
No-one, has ever found anything wrong with any of those other switches, or there would be AD's.
Thus there is not a problem with 787 Fuel Switch locking features.
July 13, 2025, 23:47:00 GMT
permalink Post: 11921787
This just popped up on my news feed - seems relevant...
Amid Air India probe, US FAA, Boeing notify fuel switch locks are safe, document, sources say
Amid Air India probe, US FAA, Boeing notify fuel switch locks are safe, document, sources say
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 FAA's 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, the FAA said it did not have anything to add beyond the notification.
Boeing also referred to FAA's 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.
July 14, 2025, 00:43:00 GMT
permalink Post: 11921807
Am seeing reports pop up suggesting there is a "chip" that needs replacing, which could have caused the issue.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn’t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn’t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
July 14, 2025, 00:50:00 GMT
permalink Post: 11921812
During the design phase, the GE types fought back very hard at the QWR requirement - as I've noted previously, it's a very difficult requirement to meet - and doing the actual flight testing to show compliance does significant damage to the engine (as in a several percent loss in engine efficiency). But the FAA has a very specific requirement that must be met (documented in an "Issue Paper"), and they make the rules.
July 14, 2025, 00:55:00 GMT
permalink Post: 11921813
Am seeing reports pop up suggesting there is a "chip" that needs replacing, which could have caused the issue.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn\x92t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn\x92t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
Each FADEC has two independent channels - if one channel has a fault that makes in incapable of controlling the engine, the other channel takes over. This happens in milliseconds - quite likely the pilots never know it happens. There are two engines.
The chances that this failure could affect both channels of both engines within a second or so is literally trillions to one.
July 14, 2025, 01:36:00 GMT
permalink Post: 11921820
Am seeing reports pop up suggesting there is a "chip" that needs replacing, which could have caused the issue.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn’t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
Not sure what chip, or the validity of the claim generally, and why its only coming from him.
I believe the FAA has - together with GE, General Electric, the engine manufacturer - has issued a service bulletin, i.e. I believe it was about 11,000 cycles, they will have to replace the chip. And if it is not replaced or maintenance isn't done correctly, it could lead to intermittent loss of signal. Once you have a loss of signal, the fuel isn’t commanded i.e. in the cut off position, then there's no fuel going to the engine
I can't post URL's but search for Marko Chan and it pops up pretty easily from a few sources.
July 14, 2025, 08:14:00 GMT
permalink Post: 11921939