Air India crash

[Old Farang]

Not sure just where to post this. How most reporters have no idea what they are talking about, the following has to take first prize in the following.


https://www.msn.com/en-au/news/other/aviation-expert-on-take-off-risks-and-investigation-after-air-india-crash/vi-AA1GAyKy?ocid=msedgdhp&pc=EDGEXST&cvid=c6e53bbcd8c 0443196ddf5be6538862f&ei=47

[V8Ian]

Aviation expert? Well we all know what an expert is. She appears to an expert at stating the bleeding obvious. [bighmmm]

[Tins]

You don't know what you don't know. And she apparently knows nothing.


https://youtu.be/mSo3DZP-FJ4'si=osEOXDQhrcLPvaFw

[JDNSW]

But Juan does - and admits when he doesn't know. But to me it looks like the flaps were retracted instead of the undercarriage. But I don't know that, and the data is limited and blurry.

[Tins]

But Juan does - and admits when he doesn't know. But to me it looks like the flaps were retracted instead of the undercarriage. But I don't know that, and the data is limited and blurry.
It would, however, explain the loss of lift if indeed that is what happened. Too soon for speculation, let alone hyperbole from “aviation experts “.
RIP

[grey_ghost]

That plane was in Melbourne a few weeks ago. I have flown the flight from Melbourne to Delhi multiple times now - I have also flown some internal flights on Air India…

Time to change airlines…

[p38arover]

There will be numerous YouTube videos telling us what the armchair experts think. Then there will be the clueless journalists writing rubbish.

I’ll wait for the official report and/or Air Crash Investigation.

[Eevo]

But Juan does - and admits when he doesn't know. But to me it looks like the flaps were retracted instead of the undercarriage. But I don't know that, and the data is limited and blurry.

i've only got a recreational pilots licence (and ive not looked at any footage for longer than 5 seconds) but once the plane is in the air, shouldnt retracting the flaps just slow down the rate of assent? not cause a decent.

[Eevo]

I’ll wait for the official report and/or Air Crash Investigation.

me too.

[Tins]

I agree, Ron, but I'll stick with Juan. He is a pro and measures his responses, and retracts if/when he's wrong.

[Tins]

https://youtu.be/MPk31EhtakE'si=HzRi2VWDOcrvQlzm

[RANDLOVER]

i've only got a recreational pilots licence (and ive not looked at any footage for longer than 5 seconds) but once the plane is in the air, shouldnt retracting the flaps just slow down the rate of assent? not cause a decent.


Which makes me wonder if it lost power, so the poor pilot had the gear down hoping to land it somewhere.

[BradC]

If it lost power there'd be no hydraulics to bring the gear up.

[JDNSW]

The gear was never retracted. but from that video it does suggest an engine failure is a possibility. But also it raises the possibility of something happening to the electrical or hydraulic systems, perhaps resulting from maintenance failures or manufacturing errors surfacing (such as incorrectly installed pipes or wiring that have eventually failed).

And if it was an engine failure, the question is why? In theory the aircraft can continue its takeoff with one engine failing at the most critical time, but with aircraft at maximum takeoff weight (likely on this flight) the safety margin is not all that large, and could be eroded to nothing by factors such as failure to retract u/c (whether pilot error or systems)and deviations from specified configuration such as flap settings, airspeeds, etc.

Double engine failure is extremely unlikely, with one possible reason I can think of - fuel contamination.

From what Juan has said this looks like being a complex investigation.

[Tins]

If it lost power there'd be no hydraulics to bring the gear up.

That's what the RAT is for. However, if both engines failed the gear wasn't going to save them.

[Tins]

Also as Juan says, it's imperative there are answers sooner rather than later. The last thing the industry needs is more speculation re Boeing. As this seems to be the only 787 crash so far, I doubt it, but we all know how the media works. Search "Boeing 787" and the top hits are the Air India crash.

[p38arover]

I agree, Ron, but I'll stick with Juan. He is a pro and measures his responses, and retracts if/when he's wrong.

I believe he is an airline pilot so he knows his stuff. I haven’t yet watched his video.

[V8Ian]

Single engine failure looks unlikely, there is no yaw. As pointed out by JD, short of fuel contamination, a double failure is extremely remote.
Even with a fuel issue, the chance of both engines being affected precisely, simultaneously is almost unheard of.
Pure speculation, from one who has never flown a commercial plane, it could be that the flaps were retracted in error, instead of the gear.

[JDNSW]

That was my initial thought - it woud not be the first time that has happened - there are good reasons why most modern aircraft have the gear switch shaped like a wheel and the flap switch a flat plate. But if Juan is correct in diagnosing the RAT being deployed, it is not something that simple. Adding to this, is that the Indian airworthiness authorities have issued an urgent notice for all 787-9 &9s fitted with that GE engine have an engine inspection. I assume the notice has details of what is to be inspected, but have not heard what it is.

And as far as I can determine, this is the first fatal accident involving a Dreamliner.

[Tins]

From what I understand the Dreamliner has the flap control as a lever in a quadrant just to the right of the throttle levers. It would seem impossible to mistake it for the gear control, as John says. They design the things that way.
I also believe that the thrust reverser controls are similarly unique. Of course, they would probably have been obvious in the video but it was a thought.

[JDNSW]

If someone switched flaps up instead of gear up, it would not be something as simple as wrong switch. But both operations (gear up and flaps up) are part of the normal procedures after takeoff, so it is conceivable that a flustered pilot could be mentally at the wrong place in the checklist, but this seems unlikely unless something else had really gone wrong.

(I am not sure of the normal procedure for this plane, but typically gear up is as soon as the plane is airborne and you have a stable climb, and flaps will be retracted , usually in stages, as airspeed increases, but this is very dependent on the aircraft and the airport and company procedures.)

[Old Farang]

Whatever happened the aircraft only flew for 30 seconds. There were either no flaps set, or very minimal. (5?) No way that full flaps would retract in the time that the aircraft was off the ground.

[Eevo]

another angle
https://www.youtube.com/watch?v=7E3HP-KuGZk&ab_channel=10NewsFirst
i think that makes engine failure more likley

[Tins]

The only thing really clear in that vid that I can see is the gear was down. Can't really see the flaps, but that could be telling in itself as they are big items. The climb out never seems stable to me, but that could simply be my own projection. Pity there was no sound.

[Tins]

Never seen this guy before. I'm putting this here FYI.


https://youtu.be/8XYO-mj1ugg'si=V2cidMQYZntw8Bps

[Tins]

Of course, it's all speculation, but the hardest thing to understand, at least for me, is why all the redundancies built in could fail, if indeed they did. That last vid mentions a MAYDAY call. Doesn't rule out pilot error, doesn't imply it either.

[Old Farang]

In that last video he says that there are 3 ways that the RAT can deploy. What he doesn't say is that it can also be deployed manually.

[Tins]

In that last video he says that there are 3 ways that the RAT can deploy. What he doesn't say is that it can also be deployed manually.

Noticed that. I wondered if they had time to deploy it. Didn't have time for much else.

[Old Farang]

Although I still look at this place from time to time, it becomes clogged up with basic BS from would be experts. I will post the following as it presents a new angle, albeit not from a pilot:

Plane crash near Ahmedabad.. - Page 60 - PPRuNe Forums (https://www.pprune.org/accidents-close-calls/666472-plane-crash-near-ahmedabad-60.html#post11901816)

poster: SpaceQuality

Boeing TCMA Patent US6704630B2

There is one system implemented in the 787, that has the authority to shut down the engines, based on software subsystem decision. Interestingly - according to the description in the patent below - the same TCMA software package determines the shutdown decision, in both redundant subsystems.

[Tins]

Boeing TCMA Patent US6704630B2

There is one system implemented in the 787, that has the authority to shut down the engines, based on software subsystem decision. Interestingly - according to the description in the patent below - the same TCMA software package determines the shutdown decision, in both redundant subsystems.




It couldn't have. Could it? Won't go well for Boeing if it did.

[JDNSW]

The flight data recorder has been recovered, and should directly answer this. But as you say, if it did .......... look to the immediate grounding of all affected aircraft.

[Tins]

And the CVR? Have they found that?

[Eevo]

i trust this guy

https://www.youtube.com/watch?v=W-MAiI_p748&ab_channel=Greg%27sAirplanesandAutomobiles

[V8Ian]

Which leaves a couple more theories. A, someone turned the key off, or B, the choke was pushed in too soon. [wink11]

[BradC]

And the CVR? Have they found that?

The 787 has a pair of "EAFR" which record data, voice, location parameters and a few other bits and bobs I can't remember. There's one forward and one aft and they both record everything. The forward recorder also has 10 minutes battery backup.

They've both been recovered, so they should have everything they need.

[Tins]

https://youtu.be/dIgnR0zw3FU'si=9tDSUQeRGBx_Z-N2

[Tins]

Can't speak to the veracity of this. Can't really say I even understand a lot of it on one viewing, but you may find it interesting. Also the comments.


https://youtu.be/M_8CYyZRWXE'si=hw3nMImfgaBata9S

[JDNSW]

I understand what he is saying, and it makes sense, as a possible scenario. But it is not the only one. The answer will lie in the data recorders, but if this scenario is confirmed, Boeing is in trouble!

[Tins]

Deep trouble. Would just about be the end of Boeing as we know it. After the MCAS debacle it’s difficult to conceive of any way out for management. I seriously hope it isn’t the case, as we don’t need a major collapse, but perhaps a breakdown back to pre MD takeover days might be necessary, although it may be impossible.

[JDNSW]

Not only Boeing in trouble - the world's airline industry as well. Most of the world's airline fleet is Boeing, and the only viable replacement is Airbus - but last I heard their order book is full for at least four years, and it would take years for them to make significant increases in production rates.

So let's hope that some other scenario is confirmed. Although the one proposed above is certainly possible - I did not realise how this aircraft is so electrical power dependent. And given it is, it seems that a lot of the equipment is excessively fault prone, probably due to poor quality control from the design phase to production.

Probably a direct result of MBAs in control.

[Eevo]

whats the old says? if its a boeing, i'm not going!

[BradC]

Can't speak to the veracity of this. Can't really say I even understand a lot of it on one viewing, but you may find it interesting. Also the comments.

One huge flaw in the video. The FADECs on the 787 have 3 not 2 power sources. The video is correct in that there are 2 on-board DC busses that supply the FADECs, and yes both of those could have failed for the reasons he outlined. The FADECs on the 787 donks have a tertiary power source, which is a permanent magnet alternator on each engine.

Once those engines are started, all they require is air, fuel and a throttle input. That's it. No different in principle to QF32 where the uncontained turbine failure in #2 severed the control and power inputs to engine 1, which meant it continued to run and could not be shut down (a mate works for RR in the UK and was part of the investigation and remediation process). Once running, it requires a positive signal to the FSOV to cut the fuel supply to the engine. The FSOV is latching and requires a signal to change state. No power, no change state. Even totally disconnected from the aircraft systems, it will continue to run as long as it has fuel. The worst possible outcome is the throttle lever is returned to idle and the engine will respond by powering down to idle. It still won't stop unless something catastrophic happens and it trips the TCMA software. Even an engine at flight idle will still generate both power and hydraulic pressure to control the aircraft and prevent the RAT from deploying. Also, the RAT on the 787 is spring loaded (thus the bang on deployment). It can only be retracted on the ground by maintenance staff, so even if the APU had fired up, the RAT would still be out.

The throttle input is literally a hard-wire from the throttle lever to the FADECs. Not networked and not subject to any other part of the aircraft systems. So it would take physical cable damage to disconnect the link between the lever and the engine.

Now, if both 28VDC busses went down that's going to impact the data recorded by the FDRs, even though the front recorder will have at least captured the cockpit audio because al that has a 10 minute battery backup. But a massive aircraft electrical failure won't have stopped both engines provided there wasn't an issue with the TCMA software. The TCMA is an integral part of the FADEC and there is a lot of speculation around that. The TCMA is only active when both the WoW (Weight on Wheel) and radar altimeters *both* say the aircraft is on the ground. Yes, perhaps a failure there, but the FDR should illustrate that if it was a problem.

This is a complex and nuanced investigation. There is a lot of internet conjecture by people who shoot from the hip.
I'm not an expert by any means, but before I judge a source I tend to do a bit of digging to understand the underlying systems. I'd put a nice bottle of red on this fellow being wrong.

At the moment if I had to posit a theory, it'd have to lie somewhere between a catastrophic simultaneous FADEC software issue or some form of contamination causing thrust rollback and engine failure on climbout. Then again, I'm not a pilot and have about 1.5 hours behind the stick of a Cessna 152, so aside from complex system theory and integration and a couple of years working around Emirates Engineering services, what would I know?

[Tins]

what would I know?

More than me, clearly. Thanks for that breakdown. As I said, I can't vouch for any of the vids, which is why I usually say FYI. . I would listen to Juan above most of the pundits, but he is a pilot, not a maintenance engineer, far less a designer. Of course, with something of this nature speculation will be rife until the NTSB report comes along to fill the vacuum. That could take years, although I would expect a prelim in the next few months.

I'm not a pilot either, Brad. Learned to fly in a 150 Aerobat and a Piper PA 28, but do not have a ppl. But flight has always fascinated me. The complexity of modern airliners is intimidating. As John says, we need to hope that this one cannot be laid at the door of Boeing, unless it leads to a restructure of that company and a return to the engineering excellence they were famous for.

[Tins]

One troubling development I have seen, which has nothing to do with Air India or Boeing, is the plethora of AI clickbait videos which have sprung up trying to piggyback on a tragedy to build a YT channel. Life(s) really can get low sometimes. There are plenty of examples of this tactic all over, from  or Android phone "releases" to Sasquatch vids. It's ruining the experience and I wish it would stop. But this one, and the 737 MAX stuff, is beyond the pale.

[V8Ian]

I'm not promoting the views expressed in this video, posting purely for consideration and discussion.


https://youtu.be/6OMNlQPOHhc'si=EcGc76C2yDaeq1sZ

[BradC]

I won't buy into any clickbait, let alone one that has tucker carlson on it.

We have a small pile of known facts which would all point toward a double engine failure. We have 2 EAFR recovered, both of which are readable. Now we wait.

[V8Ian]

I thought it was a bit clickbaity, but surely if it was purely speculative or downright untrue, Boeing could crush him legally.
I've never heard of Tucker Carlson, does he have a sensationalist reputation?

[RANDLOVER]

Tucker was on the FOX news channel, until they parted ways, and recently went to Russia to interview Putin.

[BradC]

I've never heard of Tucker Carlson, does he have a sensationalist reputation?

Does the Pope wear a funny hat, a bear **** in the woods or the Trojan horse have a wooden dick?

[RANDLOVER]

Seems the preliminary report says that the fuel to both engines was switched off seconds before the crash!

[ozscott]

Captain Steeve is on it. https://youtu.be/MD64uYK926o'si=gL1R75_YDfgOr6Ut

[Tins]

FYI:


https://youtu.be/-a4kpQHvEXU'si=c4KX4wJKbmX9MltT

[Slunnie]

I bet Boeing and the refullers are relieved, however I wonder what changes they can implement to prevent it happening again. I'm assuming the switches were accidentally bumped somehow.

[Graeme]

I really hope that such switches couldn't be accidentally bumped, but possibly operated in error when other similar switches were intended.

[Old Farang]

Preliminary Report VT-ANB.pdf (https://aaib.gov.in/What's%20New%20Assets/Preliminary%20Report%20VT-ANB.pdf)

[Old Farang]

Video of switches. Note that those particular switches have a "guard", plus it appears they need to be lifted to operate.

Watch: Role of plane fuel switches explained (https://www.bbc.com/news/videos/cx2vrdd5xkeo)

[Tins]

In comments from pilots familiar with the switches it would seem to be impossible to operate the switches accidentally.

[JDNSW]

Yes. The report will be a big relief for Boeing, if there is nothing else - but Air India and Tata will have more problems.

It certainly tends to implicate at least one of the pilots, but it therefore suggests problems with Air India's governance or training. The reports say both pilots passed breath tests prior to the flight, but the very fact that AI finds this necessary as a routine matter does suggest the possibility that the results may have been perhaps less definitive, since it suggests there could be an incentive to find a way round the tests..

[Tins]

https://youtu.be/wA_UZeHZwSw'si=y6U-kfLByJjex3mR

[Eevo]

In comments from pilots familiar with the switches it would seem to be impossible to operate the switches accidentally.

correct but human factors may have some factor into it and the pilot thought turning off the switches was a good idea.

[JDNSW]

Actually, there seems to be further twist. There is an airworthiness inspection directive apparently for an inspection of the switches because some were incorrectly assembled and the locking did not work. But the AD was not compulsory, and it appears that AI did not do these inspections on this aircraft.

If the locking mechanism was not effective on this plane (Are they sufficiently undamaged to tell?), the blame can be distributed between the airline's maintenance and pilots and manufacturer and the FAA (their airworthiness certification and directives responsibility).

[Graeme]

A news report stated that the cockpit voice recorder heard one pilot asking the other pilot why he switched off the fuel whereupon the other pilot said that he didn't. Might they have vibrated off?

[Arapiles]

Actually, there seems to be further twist. There is an airworthiness inspection directive apparently for an inspection of the switches because some were incorrectly assembled and the locking did not work. But the AD was not compulsory, and it appears that AI did not do these inspections on this aircraft.

If the locking mechanism was not effective on this plane (Are they sufficiently undamaged to tell?), the blame can be distributed between the airline's maintenance and pilots and manufacturer and the FAA (their airworthiness certification and directives responsibility).

Yes, it didn't seem likely that someone would turn them off or not be seen doing it - an existing fault would also explain the conversation between the two pilots. But that hasn't stopped on-line "experts" saying that it was intentional and one of the pilots must have done it deliberately.

You would think that this would now mean that all of these planes will now be grounded whilst this issue is checked and fixed.

[JDNSW]

Yes, or at least the non-mandatory AD made mandatory.

[BradC]

Actually, there seems to be further twist. There is an airworthiness inspection directive apparently for an inspection of the switches because some were incorrectly assembled and the locking did not work. But the AD was not compulsory, and it appears that AI did not do these inspections on this aircraft.

The prelim report says :


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.

So that won't have been a factor.

[Tins]

Yes, or at least the non-mandatory AD made mandatory.

Sorta puts it back on Boeing, and of course the various Safety Bureaus. Boeing, of course, cannot enforce any mandates, but they can stress the importance of any ADs. I'm not trying to hang them out to dry here*, but I'll bet they will come under scrutiny, given the lack of urgency shown in the MCAS matter. Watching to see if these ADs now become mandatory, for ALL Boeing aircraft with similar switches. Juan mentions that the 737 series has them. I wonder if they are a generic, or Boeing specific, item. One comment from a pilot I read suggested they should be moved to the overhead, and given an isolated location up there. Seems like a commonsense idea to me.

Juan also mentions the senseless speculation and AI slop around this incident. I mentioned before that there were many trying to piggyback on a tragedy for views and clicks. Juan is spot on. I am guilty of the speculation thing, which is human nature I guess, but not the self aggrandisement. I just hope the lessons here are learned by the entire industry.

* I'll bet many people are.

[Tins]

So that won't have been a factor.

Which leaves pilot error or malfeasance, unless the fault appeared after the inspection. Hard to see it any other way. But, speculation. As Juan noted, we may never know for certain. But steps need to be taken to prevent a recurrence.

[BradC]

Which leaves pilot error or malfeasance, unless the fault appeared after the inspection.

The "fault" identified in the AD is a manufacturing defect whereby the switch was not fitted with the guard to prevent it being toggled without lifting the handle. It can't just appear. That AD was also related to switches fitted to later model 737's. The fact those switches were also used on 787-8's prompted the "better check that also" but I can find no information on faulty switches actually being found on 787's. Regardless, the panel containing those switches was replaced twice on that aircraft, the first time being a year after the AD was issued.

There are plenty of previous accidents whereby the CVR has been used to correlate cockpit actions. Switches like those have a nice "click" and accident investigators are bloody good at identifying the slightest noise in the recording.

My opinion is the report as issued is written to specifically exclude any factor which may impact other aircraft (design & maintenance primarily) such that there are no actions required on the part of other parties (Boeing or airlines) and nothing more. I suspect they already have a pretty good idea what happened, but there's a lot of forensic investigation of the available data required to put the findings beyond reasonable doubt, so we'll have to wait a couple of years for the final report to really know.

If you haven't read the prelim report, you should. It's not long and it's written in a manner anyone with the slightest technical background would understand clearly.

[Tins]

The "fault" identified in the AD is a manufacturing defect whereby the switch was not fitted with the guard to prevent it being toggled without lifting the handle. It can't just appear.

I was referring to Juan's comment re the switches perhaps not locking correctly.

[Tins]

Interesting. FYI.


https://youtu.be/CoTsvyA-bRw'si=mOPJVBg9HYELIMSG

[JDNSW]

Just because the swittches were replaced recently does not necessarily mean that they were not lacking the locking mechanism. After all they came from Boeing presumably, and their QC has been a little hit and miss recently.

[Tins]

Just because the swittches were replaced recently does not necessarily mean that they were not lacking the locking mechanism. After all they came from Boeing presumably, and their QC has been a little hit and miss recently.

My feelings also. I also believe the AD should have been mandatory. I know that policing internal flights can be difficult, but international is a different story.

[Old Farang]

Several people have mentioned that the switches have been changed. How I read it is that the throttle modules have been changed twice. The switches are not part of that module, they are separate, close but not part of it. Boeing are saying that the switches are not a problem, and that is why the FAA issued a SAIB, not an AD.

[Slunnie]

I was watching a review of the report. It was suggesting the switches were not accidentally turned off. It seems that the switches were shut down per protocol (Engine 1, 2 secs, Engine 2) just after rotate. The other pilot (they're not sure which one) said why did you shut the engines off, the response was that I didn't (commentator suggested the response was as per a child would, rather than one of surprise), 4 secs then rat deployed, then the engines were restarted as per protocol. One motor restarted and began spooling up and began to generate thrust, the other motor restarted but didn't begin generating thrust and then they crashed.

[BradC]

Read the report. The switches were turned off in sequence a maximum of 1 second apart (the sampling rate of those channels in the FDR). The CVR records multiple channels including both pilots headsets separately. I guarantee they know precisely who said what and when.

The preliminary report serves to let the rest of the aviation world know this was not a fault they need to be worried about. That is it.

The rest will have to wait for the final report.

These are 4 pole switches with a pair of redundant data routes and direct wiring to the fuel cut off solenoids / FADECs in the relevant engine. At least 2 of those channels per switch is logged in the FDR so they know damn well there was no mechanical or electronic failure to worry about. They’ll also know from the remainder of the cockpit conversation pretty much what went down (did the PF call for gear up and then the PM cut the fuel instead of raise the gear?, or whatever really went on) so there’ll be a lot of fine correlation (sounds in the cockpit correlating with FDR logs) and background investigation to do before the final report is issued.

in the mean time, it wasn’t a mechanical or maintenance issue so the rest of the world can keep flying.

[Ferret]

Claims have been made (https://www.financialexpress.com/business/airlines-aviation/ai-171-crash-boeing-787-experienced-fuel-switch-cut-off-in-2019-too-says-us-aviation-expert-japan-pilots-never-touched-it/3917100/) by a former Inspector General of America's Transportation Department that the fuel cut off switches on a 787 have transitioned from 'run' to 'cut off' on at least one previous occasion.


...The [former] investigation revealed the plane software made the 787 think it was on the ground and the Thrust Control Malfunction Accommodation System cut the fuel to the engines...

As I understand it, the black box logs show both fuel cut off switches transitioned almost simultaneously to 'off' but also show to have later transitioned back to 'run' and to be found physically in the 'run' position at the crash site.

I would have expected if the Thrust Control Malfunction Accommodation System had played a role in this occasion then the black box logs would have shown it.

[BradC]

Claims have been made (https://www.financialexpress.com/business/airlines-aviation/ai-171-crash-boeing-787-experienced-fuel-switch-cut-off-in-2019-too-says-us-aviation-expert-japan-pilots-never-touched-it/3917100/) by a former Inspector General of America's Transportation Department that the fuel cut off switches on a 787 have transitioned from 'run' to 'cut off' on at least one previous occasion.

Yeah, nah. That was a dual engine failure when the aircraft was already on the deck triggered by the TCMA when the pilot selected the thrust reversers. The engine cut off switches did not move, and the FDR recorded a TCMA triggered cutoff (as they do on the 787 EAFR).

Incident Boeing 787-8 Dreamliner JA825A, Thursday 17 January 2019 (https://asn.flightsafety.org/wikibase/220880)

Mary Schiavo is a bit like Geoffrey Thomas and renowned for mis-reporting.


...The [former] investigation revealed the plane software made the 787 think it was on the ground and the Thrust Control Malfunction Accommodation System cut the fuel to the engines...

That was because the aircraft *was* on the ground. Pilots don't try and activate the thrust reversers in the air. Well, it has happened a couple of times but the results were always bad.

Edit : I actually read the original article linked. She's more of an an idiot that I thought.


In a previous interview with the FinancialExpress.com (https://www.financialexpress.com/), Schiavo hinted at a possible TCMA (Thrust Control Malfunction Accommodation) failure that could have led to the crash. However, when the AAIB report came out, it did not mention TCMA. TCMA informs FADEC about whether the aircraft is on the ground or in the air, and if it believes the aircraft is on the ground, it may automatically throttle back the engines, without the pilot's input.

?I think it should be on the table in the investigation. It happened before, and the 787s are around the same age. Was the 787 aircraft inspected for those TCMA flaws? That is a very big question right now.?



A) The TCMA is a piece of software inside the FADEC that specifically shuts an engine down if it thinks it is "running away" un-commanded. It can't "throttle back the engines", however it can cut their fuel supply (see B )
B ) Once the TCMA trips there's no restarting from inside the cockpit. It has to be reset as a maintenance action.
C) The TCMA has several discrete reporting parameters in the EAFR. The recorder data is very clear if the TCMA is involved. These are unrelated to the monitoring items for the fuel cut off switches.
D) The aircraft was off the ground, so the TCMA is disabled anyway. The TCMA does not "inform the FADEC", it is part of it and the aircraft informs the assembly using both weight on wheel sensors and RADAR altimeter to determine whether or not it is on the ground.