Preliminary report into Air India crash released • Hacker News Board

Re: Preliminary report into Air India crash released

#821

Post by WalterBright » Sun, Jul 13, 2025, 6:00 AM UTC

mshockwave wrote: post #810

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…

tangent: I believe Air Force and Navy have loosen the vision requirement quite a bit. IIRC the new rule only measures the corrected vision, regardless how you corrected it, including wearing glasses.

My dad had 20/10 vision. He was always first to identify enemy aircraft. They didn't have onboard radar at the time.

Wearing glasses still has issues. I have astigmatism, and so if I turn my eyes but not my head, I receive a warped view of the world. This is why I was simply terrible at baseball, tennis, etc. My brain could not adapt to this. I have difficulties with depth perception as a result, too.

I was more or less born to be a nerd. It's pointless to fight my fate :-)

Re: Preliminary report into Air India crash released

#822

Post by WalterBright » Sun, Jul 13, 2025, 6:02 AM UTC

throwaway48476 wrote: post #797

WalterBright wrote: post #747

Earlier quoted context omitted.

The pilot's inputs are the thumb switches, and they override MCAS. Additionally, the stab trim cutoff switch overrode both MCAS and the thumb switches. Using both easily and successfully averts MCAS crashes, as proven in the first incident (there were three, but only two are reported on).

There were also a lot of MCAS near misses.

I only heard of one. I'm interested in others, if you have references.

Re: Preliminary report into Air India crash released

#823

Post by WalterBright » Sun, Jul 13, 2025, 6:10 AM UTC

throwaway48476 wrote: post #796

WalterBright wrote: post #749

Earlier quoted context omitted.

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…

It's good that you're still around to correct misinformation about MCAS. I've seen so much misinformation about it, including from paid "experts". The Wright brothers succeeded because they were pioneers in wind tunnels and aluminum engine blocks.

Thank you. I've had commercial pilots email me telling me I was correct and to keep on the good fight :-)

The Wrights did a lot more than that to be successful. Their innovations were:

1. using a wind tunnel to correctly get lift and drag coefficients for various wing sections (as you wrote)

2. first aviation engine (high power/weight ratio) (as you wrote)

3. first propeller theory, enabling 90% efficiency (other aviation propellers were 50% efficient)

4. first 3-axis control system

5. identified and solved adverse yaw problem

6. first research and development program, where problems were identified in advance, and a machine was developed to solve each problem, then the solutions were put together to make the 1903 Wright Flyer

7. kept meticulous notes on all their work and preserved the evidence of their success, such as photographs and notebooks. Exacting replicas have been built, and their flight characteristics match the Wright's results

Re: Preliminary report into Air India crash released

#824

Post by dwattttt » Sun, Jul 13, 2025, 6:16 AM UTC

WalterBright wrote: post #820

dwattttt wrote: post #806

Earlier quoted context omitted.

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 w…

It seems trivial that it's better than option 1; in both cases a mentally ill person is flying the plane, and in one of them a health professional is involved in managing the condition.

For option 2 I'll confess to not being sufficiently familiar with the gamut of what can be considered a mental illness, such that I couldn't tell you whether a person under management for such is a safer pilot than someone undiagnosed, or the median pilot. I'd be mildly surprised if you were, but stranger things have happened.

As it stands, I expect these would be the same diagnostics that until ~2013 considered sexual preferences as mental health issues.

Re: Preliminary report into Air India crash released

#825

Post by manquer » Sun, Jul 13, 2025, 6:30 AM UTC

throwaway48476 wrote: post #809

manquer wrote: post #719

Earlier quoted context omitted.

it only guarantees an accident it doesn’t guarantee death of the pilot, at such low altitude and speed anyone can survive as the one passenger did . Why would anyone risk potentially surviving a sabotage like that ?

A fully fueled plane crashing in takeoff guarantees a huge fire.

That doesn’t mean the cockpit will burn .

The wings hosts the engine and a good portion of the fuel is quite a bit back from the nose in a big plane like 787. The engines lost power and hit just 180 knots just 4 seconds after the plan lifted off. The plane could have just easily broken up differently where the nose crashed in a different spot than where the fire would likely start.

At such a slow speed and altitude they could even have well crashed inside the airport perimeter and got a quicker/ better emergency response from the fire units at the airport.

Attempting this during takeoff or landing when the pilot monitoring is fully engaged and closely observing would be most difficult to execute .

Re: Preliminary report into Air India crash released

#826

Post by throwaway48476 » Sun, Jul 13, 2025, 6:42 AM UTC

WalterBright wrote: post #822

throwaway48476 wrote: post #797

Earlier quoted context omitted.

There were also a lot of MCAS near misses.

I only heard of one. I'm interested in others, if you have references.

https://www.dallasnews.com/business/airlines/2019/03/12/seve...

I just remember that it happened commonly enough to US pilots. American pilots always recovered quickly enough that it didn't make the news before the fatal crashes.

Re: Preliminary report into Air India crash released

#827

Post by vachina » Sun, Jul 13, 2025, 6:51 AM UTC

ninkendo wrote: post #643

vachina wrote: post #623

Earlier quoted context omitted.

The pilot wasn’t flying an unfamiliar aircraft.

I think the aircraft being familiar makes it worse: if you're used to going through a certain motion to do a thing, it may be one of things your brain can do without really thinking about it much, which is where the danger comes in. I've engaged my wipers when meaning to shift gears before, in my truck which has a steering column shifter. After driving the truck for years. I have ADHD and I very often let my brain go…

There is no temporal nor spatial adjacency to the switches. The switches are equivalent to the ignition on your car, you operate it in the beginning and end of your trip, and there is nothing during the trip that will involve manipulating this switch.

Re: Preliminary report into Air India crash released

#828

Post by bingo-bongo » Sun, Jul 13, 2025, 6:56 AM UTC

patch_cable wrote: post #689

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’m more familiar with the 737 (as a hobby, not as a pilot), but for that aircraft the “loss of thrust on both engines” checklist has the start levers as the second item on the list. Note that in the checklist I am looking at the goal is to restart the engines rather than diagnose the failure and that involves these levers. I suspect you’d notice pretty quickly if they were not in the expected location.

Do you know if it says anything about restarting them simultaneously or not?

I would think trying to restart engines one at a time would be preferred, over both of them at the same time - or maybe thats not how it works..?

Re: Preliminary report into Air India crash released

#829

Post by agubelu » Sun, Jul 13, 2025, 6:58 AM UTC

manquer wrote: post #775

sgerenser wrote: post #768

Earlier quoted context omitted.

Extremely unlikely, since we can hear the other pilot ask why he turned the fuel switches. If it was an electrical glitch, he wouldn’t be able to see that they are in the cutoff position.

All we know is the pilot flying is only asking whether the pilot monitoring if he cut off - We don't know if he meant the switch specifically at all. He could also have meant engines or thrust in general. There are many other visual signals and UX indicators to know if engines are spinning down. Thrust levels, to RPM to falling speed, change in angle of attack, rate of climb, even engine noise, vibrations you expect…

I think there are a couple of factors that disprove these theories:

- The specific mention of "cut off" in the CVR is very telling. If both pilots were genuinely surprised, you'd expect they'd say something like "engine failure" or "loss of thrust" first. Noone thinks the engines have been shut down as a knee-jerk reaction to a sudden loss of thrust.

- If investigators had the slightest indication there's a software or hardware bug out there that randomly causes dual engine failures, an emergency airworthiness directive would have been issued by now. This hasn't happened.

Re: Preliminary report into Air India crash released

#830

Post by WalterBright » Sun, Jul 13, 2025, 8:02 AM UTC

throwaway48476 wrote: post #826

WalterBright wrote: post #822

Earlier quoted context omitted.

I only heard of one. I'm interested in others, if you have references.

https://www.dallasnews.com/business/airlines/2019/03/12/seve... I just remember that it happened commonly enough to US pilots. American pilots always recovered quickly enough that it didn't make the news before the fatal crashes.

Thank you, but it's behind a paywall. I did find this:

https://www.nytimes.com/2019/09/18/magazine/boeing-737-max-c...

which has detailed information, but I don't trust the NYT. The article also erroneously reports that the MCAS trim rate is twice the speed of manual trim. The trim rate for both is 0.27 degrees per second.