Posts about: "RAT (All)" [Posts: 683 Pages: 35]

Someone Somewhere
July 01, 2025, 10:19:00 GMT
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Post: 11914164
Originally Posted by adfad
We know (from the 248-day bug) that full AC power failure is possible and we see from the RAT and landing gear orientation that full AC power failure was likely within ~10 seconds of leaving the ground.
I believe that particular bug is fixed, though it's always possible there's other issues causing a total AC loss.

Not really relevant to what you quoted though, as the scenario in question requires:
  • Engines running on centre tank fuel during takeoff while the aircraft is operating normally
    • We don't know for certain if this is the case. It seems to be but it's not something that happens on other families.
  • Then, total AC failure stopping fuel boost pumps.
  • Engines suction feed from contaminated/full-of-water wing tanks.

I also don't see any evidence that engine driven fuel pumps alone must be able to handle this scenario: provide enough fuel flow for takeoff and climb, even while the pitch is rotating, even in a hot environment with significant weight, even while the gear is stuck down.

I know that the engine driven pumps have documented limitations and that the regulations allow for some limitations. I know that at least one of these limitation is high altitude and I _suspect_ that the design intends for this unlikely scenario (engine driven fuel pumps alone with no AC pumps) to guarantee enough fuel flow to get to an airport and land. I also suspect that the APU is expected to solve loss of all AC generators - and as we know, there wasn't enough time for it to start in this scenario.

The aircraft has two engines and should be able to climb out on one, plus it dropped like a rock . 'Significantly degraded' thrust isn't really compatible with what we saw. You'd also expect the engines to recover pretty quickly as it leveled off.

The limitations at high altitude are primarily air/volatiles degassing out of the fuel. That's not going to be much of an issue at sea level, even if the engines are a bit higher up during rotation.
APU is a nice-to-have; it's on the MEL. If you lose all four generators, it's because of some major carnage in the electrical software/hardware and chances of putting the APU on line even if it's operating are very slim.




Someone Somewhere
July 01, 2025, 10:42:00 GMT
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Post: 11914172
Originally Posted by AirScotia
One of the things I've learned on this thread is that planes landing with the RAT deployed may be rare, but it does happen. The videos I've watched suggest that the engines were usually running as the plane landed, but of course the RAT can't be un-deployed in flight.

My question is: what caused the RAT to deploy on those flights? Presumably reports have to be submitted in those cases?
Many are maintenance or production test flights. Someone commented upthread that every Boeing widebody built gets the RAT deployed on its first flight, and I imagine some maintenance procedures require it too.

ASN has a section on electrical power incidents: https://asn.flightsafety.org/asndb/cat/ACSE

In particular try these:

https://assets.publishing.service.go...009_G-EZAC.pdf
https://asn.flightsafety.org/wikibase/233343
https://asn.flightsafety.org/wikibase/219748
https://asn.flightsafety.org/wikibase/34357
EDML
July 01, 2025, 11:38:00 GMT
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Post: 11914210
Originally Posted by Tailspin Turtle
This is my latest attempt to square the circle using all the data points and minimal assumptions. The main shortcoming of the analysis is not knowing the maximum L/D and the speed for maximum LD with the gear down, flaps 5, and the RAT extended. However, if I use a reasonable number in my opinion for the L/D in that configuration and assume that the airplane is being flown at the speed for it, it will not get to the crash site. The distance from the runway of the crash site is from a previous graphic (1.55 km); the rotation point from fdr, permalink 314; 200 feet max height above the runway being generally accepted; crash site 50 feet below the runway elevation cited previously. An average speed of 180 knots is consistent with the dimensions given and 30 seconds flight time. A flare at 50 feet will briefly increase the L/D to 20, maybe even 30 (500 feet more than shown) but still not enough to make up the shortfall, In fact, with a head wind the L/D will be lower than assumed as well as if the speed being flown is higher or lower than required for maximum L/D in that configuration. In other words, there must have been some thrust available.
You overlooked that they (the pilots) were trading speed for range/time. The aircraft slowed down by around 50kts while gliding. That is a lot of extra energy to use for range. It's visible in the video that the AoA slowly increases during the glide (I don't mean the flare at the end).
nachtmusak
July 01, 2025, 12:06:00 GMT
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Post: 11914222
Originally Posted by Tailspin Turtle
This is my latest attempt to square the circle using all the data points and minimal assumptions. The main shortcoming of the analysis is not knowing the maximum L/D and the speed for maximum LD with the gear down, flaps 5, and the RAT extended. However, if I use a reasonable number in my opinion for the L/D in that configuration and assume that the airplane is being flown at the speed for it, it will not get to the crash site. The distance from the runway of the crash site is from a previous graphic (1.55 km); the rotation point from fdr, permalink 314; 200 feet max height above the runway being generally accepted; crash site 50 feet below the runway elevation cited previously. An average speed of 180 knots is consistent with the dimensions given and 30 seconds flight time. A flare at 50 feet will briefly increase the L/D to 20, maybe even 30 (500 feet more than shown) but still not enough to make up the shortfall, In fact, with a head wind the L/D will be lower than assumed as well as if the speed being flown is higher or lower than required for maximum L/D in that configuration. In other words, there must have been some thrust available.
There is easily-correctable available data with the aircraft's altitude at pretty much the end of the runway and it is not at 200 feet (it's around 100\xb112.5 feet).

As the aircraft visibly continues to climb past that height (and for a longer period than ADS-B data covers, if the camera's perspective casts doubt on that), it seems rather clear to me that it reached its peak height past the end of the runway.

In light of this I find the fact that people keep calculating a glide from the runway to the crash site to be a bit strange. Wouldn't the first step of any math be to try to determine where it started descending?
Tailspin Turtle
July 01, 2025, 13:05:00 GMT
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Post: 11914261
Originally Posted by nachtmusak
There is easily-correctable available data with the aircraft's altitude at pretty much the end of the runway and it is not at 200 feet (it's around 100\xb112.5 feet).

As the aircraft visibly continues to climb past that height (and for a longer period than ADS-B data covers, if the camera's perspective casts doubt on that), it seems rather clear to me that it reached its peak height past the end of the runway.

In light of this I find the fact that people keep calculating a glide from the runway to the crash site to be a bit strange. Wouldn't the first step of any math be to try to determine where it started descending?
Thanks - I'm pretty sure that I read all the posts in both threads but missed that calculation as to the height at the end of the runway. I had originally guessed that the top of climb was 1,000 feet beyond the end of the runway (the current location is based on the referenced statement of the rotation point and an assumed ground speed, not air speed, of 180 kts). That still doesn't get the jet to the crash site, particularly if the post I relied on that it was 50 feet below the runway is incorrect. As far as the benefit of trading speed for distance, there wasn't that much extra speed to start with relative to the likely maximum L/D speed for that configuration and any slowing below it will reduce distance, not increase it, except of course for breaking the glide, i.e. flare at the end (there may have been a little benefit in rounding off the transition from climb to glide that I didn't take into account but I think it was small). My estimate for L/D based on known comparables that didn't include the RAT was actually 12, not 13, and I assumed that they were flying at the max L/D airspeed for that configuration even though it's likely that the crew didn't know what it was (and neither do I) but were following the prime directive, "don't stall". I also didn't take into account the headwind, which would reduce the maximum L/D available and require a slightly faster airspeed to make good than for no wind.
adfad
July 01, 2025, 13:36:00 GMT
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Post: 11914278
Originally Posted by Someone Somewhere
Thrust is non-linear and complex. Reaction engines (i.e. fans, props) are generally most efficient at minimum power - lowest excess velocity. Turbine engines are generally most efficient at high power. These cancel out somewhere in the middle. With two engines at low power, you also don't have the drag from the dead engine or the drag from the rudder countering yaw.

Cavitating destroys pumps rapidly - someone upthread said replacing the fuel pump immediately is SOP if it has suction fed. Expect end of life in tens of hours rather than tens of thousands.

Some aircraft have switched to using jet/venturi pumps powered by returned fuel, like the A220. The electric boost pumps there are mainly for redundancy and are shut down in cruise; only one in each wing tank. Some A320s replace the centre override pumps with venturi transfer pumps.
Thanks for the clarifications

My question is then: what is the minimum loss of thrust in both engines (perhaps more relevantly expressed as a % in fuel flow reduction from expected) that could produce the profile we saw. I appreciate this is a figure with many variables including timing and rate of loss.

The reason I think this question is relevant is because we pretty much have 2 prevailing theories at this point:
  1. A failure, or reduction of thrust (below idle, indicated by loss of AC generators), that somehow impacted both engines, within 20s of rotation (explaining the RAT and gear orientation)
  2. Somehow a loss of all AC power, leading somehow to a reduction of thrust or failure of engines (both engines impacted identically is assumed in this scenario since all AC is lost), and was of course below the minimum thrust needed to fly with gear down at this weight and temperature
I agree that if it is completely infeasible that loss of all AC power could do anything but cause thrust reduction of X where thrust minus X is not enough, even with gear down in high temperature and significant weight at the critical moment of takeoff to cause the profile we saw, then theory 2 is invalidated. I would love to invalidate any of the theories here but I do think some specific calculations, simulations or test data is needed
jdaley
July 01, 2025, 14:04:00 GMT
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Post: 11914293
Originally Posted by Tailspin Turtle
My estimate for L/D based on known comparables that didn't include the RAT was actually 12,
L/D of 12 would have needed the aircraft to be at 270' 1km out, 13 needs 250'.

The cctv neither confirms nor denies that top of climb could be as high as 270'. My 1km/200' estimate was conservative. I guessed 160kt average over the 7s to allow for the 25007 wind
and some deceleration.

Basically you cannot rule out loss of thrust around the time of loss of electrics.

SloppyJoe
July 09, 2025, 12:45:00 GMT
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Post: 11918371
Firstly, it's not rapid cycling of the fuel control switches, you turn them off then back on and see if it starts, this can take more than a minute as you have to wait to see if the action was successful. Second problem as mentioned above, the speed was far too low for a successful relight, you would most likely end up with a hot start or no start, most likely with a lot of smoke out the back due to unburnt fuel.

edited to add, after reading about the 787 it seems it uses electrical power to start. Same sort of issue though if not enough power, which is likely given the RAT was out.

Last edited by SloppyJoe; 9th July 2025 at 12:57 .
AerocatS2A
July 10, 2025, 01:30:00 GMT
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Post: 11918727
Originally Posted by skwdenyer
Given your professional view above, how do you react to the posted Air India 787 manual suggesting that dual engine relight should be attempted at any altitude?
I don't have any comment on it other than to note that the manual is not specific to Air India. My B787-9 FCTM is identical as far as I can tell. The actual memory item for dual failure is to reset the fuel switches and start the RAT. It is also conditional on the engines being sub idle as noted by the other poster.
MaybeItIs
July 10, 2025, 01:41:00 GMT
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Post: 11918730
Originally Posted by AerocatS2A
I don't have any comment on it other than to note that the manual is not specific to Air India. My B787-9 FCTM is identical as far as I can tell. The actual memory item for dual failure is to reset the fuel switches and start the RAT. It is also conditional on the engines being sub idle as noted by the other poster.
Excellent, thank you. More and more I'm convinced, as I was at Day One, that this guy* was a genuinely excellent pilot. More sad than ever.
* (Or to be fair, these guys, this cockpit team were...)

Last edited by MaybeItIs; 10th July 2025 at 01:55 . Reason: grammar (still bad, never mind), a bit better 2nd time
Magplug
July 10, 2025, 08:59:00 GMT
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Post: 11918849
A couple of points if I may......

I don't see it written in the 787 FCOM but I have always been told that the action of resetting the Engine Cutoff switches in the event of a dual engine failure, is merely backing up what the FADECs have already done. If there is an 'engine event' the FADECs will manage ignition and fuel-flow to restore the thrust that was demanded before the event. If that management has failed then the manual resetting may be more successful. (The same holds true for the RAT, manual selection is merely backing up the auto-deployment).

Any airline pilot will tell you that executing an in-flight relight on a big engine, no matter if it is by electric start, windmilling RPM or cross-bleed assisted, can take between 1 and 3 minutes to restore power. This aircraft was airborne for less that 30 seconds. No pilot in his right mind would prioritise an in-flight relight procedure, in a situation where they had neither the time, the height nor the speed for it to succeed. I have no doubt the crew focussed entirely on pointing the aircraft at the clearest area they could see, to mitigate what would inevitably follow.
adfad
July 10, 2025, 13:18:00 GMT
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Post: 11919024
Originally Posted by Sailvi767
The data recorder has all the information most are questioning. They already know if the fuel control switches were selected to cutoff and they know if this happened before or after the loss of thrust. Perhaps the sequence of events will be more clear tomorrow. I can tell you that from aircraft rotation to loss of thrust was a very short time period. Perhaps 8 seconds. I simply won’t believe in that time period the crew were taking any non deliberate actions that would have shut the motors down.
Assuming the 2nd/3rd-hand 'leaked' info about fuel switches is even accurate the scenarios of what they know (investigators / leaker) would be:
  1. They know exactly 1 fuel switch was cut off, perhaps implying single engine failure + wrong engine shutdown
  2. They know 1 or both switches were cycled off then on, implying a last-ditch attempt at some sort reset at any point up to say ~30s
  3. They know both fuel switches were cut off, and remained off, implying sabotage
Working logically through these:
  1. If the cut off happened within 20s of leaving the ground perhaps it could explain why CCTV shows the initial climb then level for ~10s before descent. It could also explain the RAT and gear trucks perhaps if gear up was delayed? However, in this scenario they must know that the engine failed, that information would be clearly recorded and surely the leak would lead with that info? Also 'switches' is plural implying both, the radio call didn't mention single engine failure and like you say its quite hasty, even within 20s.
  2. Again assuming switches plural, this implies either of the prevailing theories of dual engine failure leading to loss of AC or loss of AC leading to reduced thrust or engine failure. However, it also seems strange to lead with that info rather than the state of the engines or electrical systems in any flight data, unless someone can explain how the data would be impacted?
  3. If this was the case then it would imply that there is no voice or engine data to explain the cut off, nothing was said and the engines were normal up until that point
KSINGH
July 11, 2025, 20:40:00 GMT
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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
Engineless
July 11, 2025, 20:40:00 GMT
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Post: 11919772
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.
In the cockpit voice recording, one of the pilots is heard asking the other why did he cutoff.
The other pilot responded that he did not do so.
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.

As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about
08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with
the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also
transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to
RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC)
automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.
The EGT was observed to be rising for both engines indicating relight. Engine 1’s core
deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to
relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to
increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11
UTC

As per the EAFR data both engines N2 values passed below minimum idle speed, and the
RAT hydraulic pump began supplying hydraulic power at about 08:08:47 UTC.
RAT in extended position
15
As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about
08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with
the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also
transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to
RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC)
automatically manages a relight and thrust recovery sequence of ignition and fuel introduction.
The EGT was observed to be rising for both engines indicating relight. Engine 1’s core
deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to
relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to
increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11
UTC
At about 08:09:05 UTC, one of the pilots transmitted “MAYDAY MAYDAY MAYDAY”.
What the hell happened in the cockpit?

08:08:42 Engine 1 and Engine 2 fuel cutoff switches transitioned from RUN to CUTOFF position.
One of the pilots asks the other why did he cutoff.
The other pilot responded that he did not do so.
08:08:52 Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN
08:08:56 Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN

Who (or what?) operated the cutoff switches?

Last edited by Engineless; 11th July 2025 at 20:53 .
DTA
July 11, 2025, 20:56:00 GMT
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Post: 11919785
This part of the report shows how early the RAT was out.



Musician
July 11, 2025, 22:09:00 GMT
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Post: 11919886
Seconds count:
As per the EAFR, the Engine 1 fuel cutoff switch transitioned from CUTOFF to RUN at about 08:08:52 UTC. The APU Inlet Door began opening at about 08:08:54 UTC, consistent with the APU Auto Start logic. Thereafter at 08:08:56 UTC the Engine 2 fuel cutoff switch also transitions from CUTOFF to RUN. When fuel control switches are moved from CUTOFF to RUN while the aircraft is inflight, each engines full authority dual engine control (FADEC) automatically manages a relight and thrust recovery sequence of ignition and fuel introduction. The EGT was observed to be rising for both engines indicating relight. Engine 1's core deceleration stopped, reversed and started to progress to recovery. Engine 2 was able to relight but could not arrest core speed deceleration and re-introduced fuel repeatedly to increase core speed acceleration and recovery. The EAFR recording stopped at 08:09:11 UTC.
That was with 10 seconds delay vs. 13 seconds for engine 2.

Time was spent with the verbal exchange, and then perhaps each pilot expected the other to put the switch back?

Anyway, the preliminary report also establishes that the aircraft had only 3-4 seconds of powered flight. (Would the gear lever be operated that early?) Everyone who saw that from the CCTV video, pat yourselves on the back.

Mayday call, dual engine failure, RAT deployment all confirmed.
TCMA was a red herring, the aircraft was firmly in air mode as the accident unfolded, and the thrust levers were at takeoff thrust the whole time.
Seamless
July 11, 2025, 22:12:00 GMT
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Post: 11919889
Spoiler
 

I wouldn't put too much significance in the "01 second" since this still is close enough for an unintentional cause.

No matter what: The design and position of the fuel cut off switches is potentially prone for mishaps.
9 lives
July 11, 2025, 23:25:00 GMT
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Post: 11919990
There is mention of fire damage or thermal damage to the centre pedestal, perhaps enough to identify the position of the switches but not to be able to determine their internal physical state relating to the detent mechanisms.
The photo of the engine switches in the report shows the toggle of both switches pretty clearly, with the caps burned off (to be expected, has zero effect on function, nor detent locking). The fact that the toggles and lower mechanism of each switch appears in the photo is pretty conclusive (a) to the position of the switches at the time of crash, and (b) that the locking detent function of the switch was functional as intended. I've worked with these switches for decades, and they are very robust. Their lesser cousin design, which also has a center detent lock position (double throw) are less robust that these (single throw) switches, and they last well too. Though I have seen them worn, I have never seen the locking function worn to the point of not functioning as a lock. And these switches would be too new to have experienced wear/damage to that point.

For myself, I have total confidence that the switches functioned as intended. Obviously they commanded the fuel valve as intended, and can be seen intact (other than the plastic caps), and in the run position, so it is safe to conclude that a mechanical/electrical fault of both independent switches at the same moment is unlikely in the extreme. The FDR data states that they were moved to "off" position, which caused the engine shutdown, then returned to "run", so they obviously were mechanically and electrically functional.

The automatic deployment of the RAT is an indicator of the airplane systems sensing an engine shutdown, as is the APU autostart. Pax 11A mentioned the green cabin lights, which, if I understand correctly is an indication of a complete electrical generation failure.The time of all these events can be plotted from recorded data, which I expect we'll see in a full report later. In the mean time, it all makes unfortunate sense.
Musician
July 11, 2025, 23:26:00 GMT
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Post: 11919991
Speculations laid to rest

I am going by the list in the excellent post here: Air India Ahmedabad accident 12th June 2025 Part 2

Anyway, here goes:

A. Misconfiguration or wrong takeoff data — OUT : 5 tons under MTOW, flaps 5, takeoff roll uneventful

B. Flaps retracted post-takeoff instead of gear — OUT : flaps 5 still set at crash

C. Low-altitude capture — OUT : throttle was at take-off thrust the whole time

D. Loss of both engines at or shortly after rotation — IN: confirmed to have occurred 3-4 seconds after liftoff

I. Bird strike/FOD — OUT

II.Fuel-related
1. Loss of electric fuel pumps — OUT
2. Fuel contamination — as good as OUT , but lab work is ongoing
3. Vapour lock — OUT

III. Improper maintenance — mostly OUT , switches might have been defective

IV. Large-scale electrical fault (e.g. due to water in E&E bay) — OUT . This would have been obvious from the flight recorder.

V. Shutdown of engines by TCMA — OUT . Conditions not met (not on ground, throttle not at idle)

VI. (Inadvertent) shutdown by flight crew
1. Spontaneous execution of memory items (fuel control switches OFF, then ON; deploy RAT) due to assumed engine malfunction — OUT from CVR
2. No indications whatsoever of an intentional shutdown for nefarious reasons — IN but unsupported

VII. Malfunction/mishandling of the fuel cutoff switches (most recent)
1. Wear or improper operation of the switches, so that they do not lock but can shift back into the OFF position. — IN

Read the previous post to this by 9 lives and reconsider VII.1
Senior Pilot


2. Spilled drink leading to short in the wiring — IN (barely) , 8 separate switch contacts must be affected in just the right way

If you never supported any of the theories that are now out, pat yourself on the back!

Last edited by Senior Pilot; 12th July 2025 at 03:40 . Reason: added comment
physicus
July 12, 2025, 00:08:00 GMT
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Post: 11920029
Timeline of known events with source attribution from the preliminary report:

08:07:33 ATC: Takeoff clearance
08:07:37 A-SMGCS: Aircraft starts rolling
08:08:33 EAFR: V1 153kts
08:08:35 EAFR: Vr 155kts
08:08:39 EAFR: Gnd-Air mode transition
08:08:42 EAFR: Max IAS 180kts, Eng 1/2 Cutoff switches activate within 1 second of each other
08:08:42 CVR: "Why did you cut off", "I did not" (exact time not specified)
08:08:42 A-SMGCS: RAT deployed (exact time not specified)
08:08:47 EAFR: Both engine N2 below min idle. RAT hyd pwr commences
08:08:52 EAFR: Eng 1 cutoff to RUN
08:08:54 EAFR: APU inlet door opens (auto start logic)
08:08:56 EAFR: Eng 2 cutoff to RUN
08:09:05 ATC: Mayday call
08:09:11 EAFR recording stops

Fuel cutoff switches operated within 1 second of each other suggests to me that the locking mechanism wasn't working as per (SAIB) No. NM-18-33. Any loose item could have accidentally (or not) operated the switches (including hands).

Last edited by physicus; 12th July 2025 at 00:24 .