←back to thread

Preliminary report into Air India crash released

(www.bbc.co.uk)
293 points cjr | 10 comments | 11 Jul 25 20:23 UTC | HN request time: 1.176s | source | bottom
Show context
decimalenough ◴[11 Jul 25 21:24 UTC] No.44536914[source]▶
> 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 switches in question are also built so they cannot be triggered accidentally, they need to be unlocked first by pulling them out.

> 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.

And both pilots deny doing it.

It's difficult to conclude anything other than murder-suicide.

replies(25): >>44536947 #>>44536950 #>>44536951 #>>44536962 #>>44536979 #>>44537027 #>>44537520 #>>44537554 #>>44538264 #>>44538281 #>>44538337 #>>44538692 #>>44538779 #>>44538814 #>>44538840 #>>44539178 #>>44539475 #>>44539507 #>>44539508 #>>44539530 #>>44539532 #>>44539749 #>>44539950 #>>44540178 #>>44541039 #
bgwalter ◴[11 Jul 25 21:39 UTC] No.44537027[source]▶
Does the Flight Data Recorder consider the physical position of the fuel switches or does it get the information from some fly-by-wire part that could be buggy?

The conversation would suggest that the switches were in CUTOFF position, but there is also a display that summarizes the engine status.

There is no conversation that mentions flipping the switch to RUN again.

EDIT: Why is there no Cockpit Video Recorder? The days of limited storage are over.

replies(5): >>44537055 #>>44537169 #>>44537239 #>>44537659 #>>44538846 #
nikanj ◴[11 Jul 25 23:01 UTC] No.44537659[source]▶
Airlines are decades behind on tech. You can get satellite internet almost anywhere on the planet and GPS can give you ten-foot accurate positioning, but we've still _lost_ planes because we haven't mandated a system that sends the realtime position of the plane over the satellite internet. The days of limited storage are still going strong in the industry.
replies(1): >>44538900 #
1. karlgkk ◴[12 Jul 25 02:51 UTC] No.44538900[source]▶
There are reasons they don’t. This is a deceptively difficult problem

Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)

And by stations, I mean aircraft. There are a TON. Current constellations probably wouldn’t even be able to handle half the current aircraft transmitting all at once. Bandwidth, in the physical sense, becomes a limiting factor

Coverage (different constellations have different coverage, which means planes would not have transmit guarantees depending on flight path). So you’d have huge gaps anyways

There have been alternative solutions posed, some of which are advancing forward. For example, GPS aware ELTs that only transmit below certain altitudes. But even that has flaws

Anyways I think we’ll see it in the next decade or two, but don’t hold your breath

replies(6): >>44538999 #>>44539252 #>>44539410 #>>44540095 #>>44540139 #>>44541286 #
2. ekianjo ◴[12 Jul 25 03:17 UTC] No.44538999[source]▶
> Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)

You get free Starlink on several airlines now, so won't that be a solved problem soon?

replies(1): >>44539416 #
3. ◴[12 Jul 25 04:15 UTC] No.44539252[source]▶
4. lxgr ◴[12 Jul 25 04:56 UTC] No.44539410[source]▶
Most airplanes regularly crossing oceans already do have satcom.

The cost of hardware and additional fuel consumption due to drag aren’t nothing, but the data used itself is essentially a rounding error. (Iridium for example has tiny antennas, and SBD data costs about a dollar per kilobyte, and position data is tiny.)

Of course, that’s all little help when a pilot acts adversarial; on MH370, the breakers for both satcom and transponder were likely pulled, for example.

replies(1): >>44540752 #
5. lxgr ◴[12 Jul 25 04:57 UTC] No.44539416[source]▶
Free to passengers doesn’t mean free to the airline, and Starlink in commercial airliners is very new.
replies(1): >>44540224 #
6. Aeolun ◴[12 Jul 25 07:36 UTC] No.44540095[source]▶
> Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)

That’s nonsense. Even when I’m flying right over the north pole my airline will give me unlimited in-flight internet for $20. Maybe antartica has worse reception, but cost isn’t the issue.

7. Dylan16807 ◴[12 Jul 25 07:44 UTC] No.44540139[source]▶
There's somewhere around 15 thousand relevant planes in the air at any time.

If you sent two updates a minute over Iridium, using their 25 byte message plan, you'd be looking at a megabyte per minute for the entire planet. That's such a tiny fraction of what that single constellation can do.

8. ekianjo ◴[12 Jul 25 08:08 UTC] No.44540224{3}[source]▶
sure but if the airline already pays for the service for passengers surely it can be used for the planes as well
9. notahacker ◴[12 Jul 25 09:55 UTC] No.44540752[source]▶
Yep. Inmarsat has this data for most of the world widebody fleet, and had it for MH370... except when transmission stopped. It's not publicly shared information, because that's what the ADS-B transponder they're all equipped with is for...
10. nikanj ◴[12 Jul 25 11:31 UTC] No.44541286[source]▶
> Cost is a big one (satellite data is still quite a bit more expensive than you think, especially with many stations)

I can pay $10 to have internet for the entire flight. Reasonably low bandwidth of course, but if I can splurge $10, the airline can.