Preliminary report into Air India crash released • Hacker News Board

Re: Preliminary report into Air India crash released

#661

Post by noqc » Sat, Jul 12, 2025, 4:27 PM UTC

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 cutoff most closely resembles the transcript from within the cockpit.

The report is actually a little cagey about whether the locks were properly installed on these switches. Said locks are supposedly optional. Until I receive a more direct confirmation that the switches were installed with their full safety features, I will assume that it is more likely for the plane to have had improperly installed switches than not, given that the shutoff was the reason for the crash, and if they turn out to have been installed, I will assume that simple pilot error is responsible until a motive for murder is found. The pilots lives are under quite a lot of scrutiny, and I do not believe that a motive for murder is likely to be found.

Re: Preliminary report into Air India crash released

#662

Post by arctics » Sat, Jul 12, 2025, 4:27 PM UTC

Throttle control module (TCM) was replaced twice in the past 2019 and 2023 which is not very usual.

Now pure speculation, both pilots have long record of flying, you have to literally pull up and move each fuel control switches to cut off. Either one of the pilots did this intentionally or control unit was faulty. Considering past history and pilot experience, my bet is on faulty controls but we will never know.

Re: Preliminary report into Air India crash released

#663

Post by cjrp » Sat, Jul 12, 2025, 4:27 PM UTC

briandear wrote: post #529

0_-_0 wrote: post #371

Earlier quoted context omitted.

Maybe as the PIC was guarding the lower end of the throttle he rested the rest of his hand on the panel cover below the throttle and, while pushing forward on the throttle, let the side of his hand slide down right onto the switches, the likeliness of which would have been exacerbated by a rough runway or a large bump. It's unlikely the left and right part of his hand would have contacted the cutoff switches at the s…

Nope. First of all, the FO was the “pilot flying” and thusly controls the throttle. The fuel shutoffs are on the left side, well clear of the range of motion throttle operation for the right seat. If the Captain were controlling throttles, it for some reason he could contort his wrist to accidentally open the red cutoff switch guards, the switches themselves move in the opposite direction of the pivot of the switch g…

The fuel cutoff switches are directly behind the throttles, in a central position. Maybe you’re thinking of the stab cutout switches?

Re: Preliminary report into Air India crash released

#664

Post by jltsiren » Sat, Jul 12, 2025, 4:30 PM UTC

agubelu wrote: post #618

jltsiren wrote: post #502

Earlier quoted context omitted.

Courts do not seek to establish the truth. They aim for a reasonable balance between false positives (innocents convicted of crimes they didn't commit) and false negatives (criminals allowed to go free). In practice, the false positive rate is probably around 5%, and innocents go to prison all the time. Air accident investigations mostly deal with one-in-a-billion freak occurrences. Commercial aviation so safe and re…

Yet Occam's razor still applies

That's not what Occam's razor means. It means that after you have exhausted all options to rule out competing hypotheses, you choose the simplest one that remains, for the time being.

Consider some explanations that are consistent with the evidence presented so far. And remember that the purpose of the investigation is to come up with actionable conclusions.

1. One of the pilots randomly flipped and crashed the plane for no reason. In this case, nothing can be done. It could have happened to anyone at any time, and we were extraordinarily unlucky that the person in question was in position to inflict massive casualties.

2. Something was not right with one of the pilots, the airline failed to notice it, and the pilot decided to commit a murder-suicide. If this was the case, signs of the situation were probably present, and changes in operating procedures may help to avoid similar future accidents.

3. One of the pilots accidentally switched the engines off. The controls are designed to prevent that, but it's possible that improper training taught the pilot to override the safeties instinctively. In this case, changes to training and/or cockpit design could prevent similar accidents in the future.

Because further investigation may shed light on hypotheses 2 and 3, it's premature to make conclusions.

Re: Preliminary report into Air India crash released

#665

Post by Rastonbury » Sat, Jul 12, 2025, 4:38 PM UTC

throw310822 wrote: post #524

tzs wrote: post #346

Earlier quoted context omitted.

> British Airways 5390: An incorrect repair causes the windshield of a plane to be blown out mid flight. A pilot is nearly sucked out. This one is a good illustration of how better design can help prevent accidents or make them less severe. The error the maintenance people made was that when they replaced the window and the 90 screws that hold it on 84 of the screws they used were were 0.66 mm smaller in diameter tha…

> the pressure difference at altitude works to hold the window in place Curious, is the pressure difference actually greater than the force of 800km/h wind pushing on the window? Or is it just for side windows?

The outward pressure is about 5-6x greater than the force of air resistance at cruising altitude

Re: Preliminary report into Air India crash released

#666

Post by wdb » Sat, Jul 12, 2025, 4:38 PM UTC

Wondering if it is save to fly with Air India at the moment

Re: Preliminary report into Air India crash released

#667

Post by cjbprime » Sat, Jul 12, 2025, 4:39 PM UTC

russdill wrote: post #458

cjbprime wrote: post #384

Earlier quoted context omitted.

Not really, though. They're both (retracting the gear, and cutting off fuel) just toggle switches, as far as your brain's conscious mechanisms go. Doing them both on every flight dulls the part of your brain that cares about how they feel different to perform. (I'm not strongly arguing against the murder scenario, just against the idea that it's impossible for it to be the confusion scenario.)

Neither is a toggle switch and the gear lever is incredibly conspicuous: https://www.aerosimsolutions.com.au/custom-products/olympus-... This would be like opening your car door when you meant to activate the turn signal.

I meant philosophical toggle switches, not physical ones. The gear can go between down and up. The fuel can go between run and cutoff. Given enough practice, the brain takes care of the physical actions that manipulate those philosophical toggles without conscious thought about performing them.

Re: Preliminary report into Air India crash released

#668

Post by lttlrck » Sat, Jul 12, 2025, 4:40 PM UTC

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.

What were they confusing the switches with though? Are there two other switches they would be toggling at that phase?

Perhaps they were very very confused and thought they had just arrived at the terminal?

Re: Preliminary report into Air India crash released

#669

Post by cjbprime » Sat, Jul 12, 2025, 4:40 PM UTC

russfink wrote: post #543

uwagar wrote: post #538

Earlier quoted context omitted.

this bathroom thing and various similar scenarios happens to me when im on weed.

Genuinely curious - could heavy marijuana use cause confusion between landing gear and fuel cutoff? Or some other drugs? (Wondering if they screen pilots for alcohol before they board an aircraft.)

The prelim report states these pilots were indeed breathalyzed before takeoff.

Re: Preliminary report into Air India crash released

#670

Post by tzs » Sat, Jul 12, 2025, 4:46 PM UTC

throw310822 wrote: post #524

tzs wrote: post #346

Earlier quoted context omitted.

> British Airways 5390: An incorrect repair causes the windshield of a plane to be blown out mid flight. A pilot is nearly sucked out. This one is a good illustration of how better design can help prevent accidents or make them less severe. The error the maintenance people made was that when they replaced the window and the 90 screws that hold it on 84 of the screws they used were were 0.66 mm smaller in diameter tha…

> the pressure difference at altitude works to hold the window in place Curious, is the pressure difference actually greater than the force of 800km/h wind pushing on the window? Or is it just for side windows?

Dynamic pressure of wind is 1/2 p v^2 where p is the air density and v is the velocity.

At sea level p = 1.225 kg/m^3. It goes down as altitude goes up. At sea level the dynamic pressure at 800 km/hr would be about 4.4 PSI.

At 20000 ft the air density is about half that of sea level, so around 2.2 PSI wind pressure. It would be around 1.4 PSI at 35k ft.

At cruising altitude planes are typically about 8 PSI above the outside pressure.

It would be maybe an interesting project for someone more ambitious then me to get a speed vs altitude profile of a typical airline flight and an altitude vs cabin pressure profile and figure at what part of a typical flight the screws on a plug window are resisting the most force.