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Preliminary report into Air India crash released

bbc.co.uk

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Re: Preliminary report into Air India crash released

#811

Post by throwaway48476 »

WalterBright wrote: post #229
decimalenough wrote: post #11

> 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. So the fuel supply was cut off intentionally. The swi…

> It's difficult to conclude anything other than murder-suicide. Remember that incident where a cop pulled out his taser and tased the suspect? Except he pulled out his pistol and fired it. The taser looks nothing like a pistol, feels nothing like it, yet it is still possible to confuse the two in the heat of the moment.

This is why the pilot doing the action annunciates it and the other pilot checks it. Pilots are trained not to silently do things.

Re: Preliminary report into Air India crash released

#812

Post by aunty_helen »

Miner49er wrote: post #758
labcomputer wrote: post #586

Earlier quoted context omitted.

> I don't know why online communities have been so quick to gravitate towards the murder/suicide theory. Because the hardware failure theories seem preposterously far-fetched and require an unnecessary multiplication of deities. Your ghost in the machine needs to be “just so” so that it can cause both switches to be read in “cutoff” nearly simultaneously. Then, 10 seconds later one of the switches needs to be read in…

There's also the timing. Maybe there's something specific about takeoff that makes it more likely for the failure to occur. However, assuming there's not, then the odds of this occuring at takeoff (the worst possible time) instead of any other time are extremely low. Takeoff accounts for a tiny percent of the plane's operation.

As explained in the text, take off loads aka g force from the plane rotating. That's the feeling that you get when the plane takes off and it pushes you into your seat.

I personally don't buy it. Why then did the switches just work after being toggled. Why did the switches go to shutoff one after the other. Why did the pilot question why the other pilot set it to shutoff? Then there's the catastrophic nature of the timing, 10 seconds earlier and they would have skidded off the runway. 10 seconds later, the engines would've relit and regained enough thrust. If there's one thing pilots are experts in, it's what to do to get yourself killed in your airframe of choice. This was calculated down to the second.

Something else that's going on, there's a bot network alive and well on twitter blaiming boeing and all things under the sun except pilot mass murder. Yet occams razor, a mentally ill pilot shut off the fuel at the right time to doom the aircraft seems tragically possible.

Re: Preliminary report into Air India crash released

#813

Post by pertymcpert »

noqc wrote: post #661
SAI_Peregrinus wrote: post #629

Assuming this is a murder-suicide and not a mistake or malfunction somehow, it's very damning of the FAA's policy to revoke the pilot's licenses of anyone seeking treatment for mental health issues. This was in India and thus not FAA jurisdiction, but it still would be a case where an untreated mental health issue lead to hundreds of deaths. By making pilots choose between their careers & medical treatment (since the…

The murder suicide angle isn't particularly worthy of assumption yet. Have you ever put your phone in the fridge? Pilots deactivate the fuel cutoff at the end of the final taxi to the gate. This makes flipping these switches a practiced maneuver , capable of being performed without conscious thought, regardless of whether they came with safety locks installed. Brain farts are a real phenomenon, and an accidental fuel…

These switches are locked into place with a spring loaded detent switch. It's impossible to accidentally switch these off.

You say muscle memory. No muscle memory is involved in fuel cut off for both engines seconds after take off. There is no procedure remotely similar.

Re: Preliminary report into Air India crash released

#814

Post by cpgxiii »

mr_toad wrote: post #755
cpgxiii wrote: post #281

Earlier quoted context omitted.

The F-16 EPU is to keep the flight controls powered so the plane doesn't immediately become uncontrollable following engine failure. The EPU doesn't provide thrust of any kind. The 787 and nearly every other commercial aircraft with powered flight controls [1] (fly-by-wire or traditional) has emergency power available via RAT and/or APU, and any fly-by-wire aircraft has batteries to keep the flight control computers…

> the maximum allowable passenger/baggage/fuel load would have been uneconomical without the margin provided by the emergency rockets. Your momma so fat… But seriously, is there a commercial aircraft that can’t climb on only engine?

That is a somewhat complicated answer. The simplistic answer is that certification criteria require all turbine aircraft (turboprop or jet) to meet minimum climb performance following an engine failure at the worst part of takeoff. Multiengine piston aircraft (almost all of which are grandfathered in under prior rules anyways) are not required to do so. As a proportion of commercial passenger aircraft, multiengine piston aircraft are fortunately fairly rare in terms of passenger-miles flown, but they are still fairly common in certain markets.

However, that answer is hiding a lot of complexity. In a multiengine turboprop, single-engine climb performance is dependent on fathering the propeller of the dead engine(s); if you don't (or can't), you will probably crash.

In all aircraft, different takeoff conditions (ambient temperature, pressure, runway length) will result in different performance (maximum takeoff weight, runway length and takeoff thrust required). In some extreme conditions (e.g. "hot and high" airports like Mexico City or Denver) this can result in a reduction of maximum takeoff weight to ensure that engine-out climb performance is maintained. Generally aircraft used in these airports are designed and/or acquired with these conditions in mind, and thus the aircraft are still profitable to operate with the reduced MTOW.

Re: Preliminary report into Air India crash released

#815

Post by pertymcpert »

gmokki wrote: post #681
yason wrote: post #672

It is known that the switches cannot effectively be flipped by accident. It is known that the switches were set to "cut-off" because they were then later restored to "run", so it was not an electrical fault (i.e. switches pointing to run but reporting cut-off). Pilot dialogue and engine telemetry confirms the cause of power loss was fuel cut-off. The question I can't help but think is how did the pilot realize it was…

I would assume that the engines cur of due to fault in the shared control system. And to restore power the pilots toggled the switches to off and then back on to get them running again. Hopefully the timestamps tell if the engines lost power before switches were turned off? Or is there some time window that was not recorded due to the lost power to systems?

Why would you assume that? The engines were providing thrust to achieve normal take off. If they did that to restore engine power why would the voice recorder have one asking the other why he cut off the engines?

Re: Preliminary report into Air India crash released

#816

Post by pertymcpert »

callmeal wrote: post #445
bigtones wrote: post #151

Each of the fuel switches on the 787 is equipped with a locking mechanism that is supposed to prevent accidental movement, experts said. To turn the fuel supply on, the switch must be pulled outward and then moved to a “RUN” position, where it is released and settles back into a locked position. To turn the fuel supply off, the switch must be pulled outward again, moved to the “CUTOFF” position and then released agai…

Or they could be inadvertently flipped if the "locking" version was not installed: (see the avherald link): >>India's media report that the investigation is NOT focussing on a human action causing the fuel switches to appear in the CUTOFF position, but on a system failure. Service Bulletins by Boeing issued in year 2018 recommending to upgrade the fuel switches to locked versions to prevent inadvertent flip of the sw…

No because the report says that the switches were turned off 1 second apart. This was a deliberate action.

Re: Preliminary report into Air India crash released

#817

Post by invalidator »

WalterBright wrote: post #749
invalidator wrote: post #744

Earlier quoted context omitted.

MCAS autonomously adjusts trim downward. The trim switches override MCAS, but when released, MCAS can resume trimming down again. The trim adjustments don't "override" the pilot's elevator inputs (MCAS has no direct control over the elevators), but they can make the controls so heavy that it's impossible to pull up.

If MCAS is running the trim, the thumb switches override it. MCAS affects the stabilizer, the thumb switches affect the stabilizer, the cutoff switch affects the stabilizer. The elevators are controlled by the control column and the autopilot. > The trim switches override MCAS, but when released, MCAS can resume trimming down again. That is correct. That is why the procedure is to return the trim to normal with the t…

> Almost right - the trim has more authority than the elevators.

Thank you, I'll update my brain and future explanations. :)

Re: Preliminary report into Air India crash released

#818

Post by throwaway48476 »

BurningFrog wrote: post #679

As an amateur UI designer I'm really surprised the plane allows a crash to be initiated without as much as an "Are you sure?" check. This is a completely computer run plane, and it surely has enough information to know this is a disastrous thing to do.

UI designers have to make it work for the lowest common denominator. Pilot training weeds out the LCD and trains for any gaps in knowledge.

Re: Preliminary report into Air India crash released

#819

Post by perilunar »

tverbeure wrote: post #791
gamblor956 wrote: post #760

Earlier quoted context omitted.

Sorry, that conclusion is just silly. I know people in the airline industry (some pilots and a number of flight attendants) and the problem is not that they're forced to conceal mental issues. The problem is that many people in aviation imagine that they need to conceal their problems. And they point to videos like this one as proof of that, ignoring that the events of discussed in the video are actually proof of the…

What about Xyla Foxlin’s case: https://youtu.be/aj0H8oVS7qg?si=X7Nux24PPbNa24Y8

Props to Xyla for speaking out. Her case is interesting because her depression was caused by hormonal birth control, and was temporary, but she’s still grounded.

Re: Preliminary report into Air India crash released

#820

Post by WalterBright »

dwattttt wrote: post #806
WalterBright wrote: post #801

Earlier quoted context omitted.

I don't see where the win is here: 1. If the pilot hides his mental illness, a mentally ill person is flying the airplane. 2. If the pilot gets treatment for his mental illness, a mentally ill person is flying the plane. P.S. When I was a teenager, I tried to join the Air Force to be a pilot like my dad. But since I wear glasses, there was no way. The AF was perfectly justified in not taking me, I understood that. I…

Where's option 3: a pilot gets treatment for his mental illness and is signed off as safe to fly a plane? For all that it's a fallible process, that seems better than options 1 & 2.

Does it? I've never heard of anyone being cured of mental illness, just drugs that relieve the symptoms. The body develops resistance to the drugs, the drugs usually come with bad side effects, and patients often go off their meds.

Pilots who develop a heart condition get their license revoked. Every pilot knows this. There's nothing fair about that, either.

Fun fact - my Air Force dad told me that when an airplane was overhauled, the chief mechanic went up on the check ride. That ensured the job was well done.

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