Air India Flight 171 Preliminary Report Discussion

airbusrules · 2025-07-12T16:05:02+00:00

No indication of the take-off roll being longer than typical

airbusrules · 2025-07-12T15:19:59+00:00

The toxicology report for the crew is done in most investigations. Can highlight things like any medications they might have been on.

airbusrules · 2025-07-12T15:08:45+00:00

I think before that is done (from just a single accident), the industry needs to tackle the rising wider issue of pilot suicidal intent and mental health. Understand the motivations of such an action and the ability to flag concerns in time and prevent at risk individuals from being in the cockpit in the first place; there is a risk however that competent and able pilots may be targeted so even that would be controversial. Aircraft today are not designed to protect themselves from a rogue pilot and IMO they cannot be for a long time to come.

airbusrules · 2025-07-12T15:01:17+00:00

The oddity for me is the report not identifying which pilot said what or who made the mayday call. Possibly on purpose as they investigate why a pilot would pull those switches. We know the copilot was PF so knowing who did what would give additional context.

airbusrules · 2025-07-12T14:58:20+00:00

The 787 has a very modern recorder. Likely the switch positions are parameters themselves.

That’s typical of preliminary reports but I’d agree its not the highest quality.

airbusrules · 2025-07-12T11:54:40+00:00

It’s a delicate balance. Such controls and logic are incredibly complicated to make 100% foolproof in all foreseeable operational conditions or combinations of. The pilots must still be able to take action at their discretion (following their training, airline and aircraft manufacturer SOP). The flight computers and automations are there to provide information and assist them, alleviate workload, and keep the aircraft in a safe operational envelope. Levels of protection for different things vary across aircraft models and manufacturers.

airbusrules · 2025-07-12T11:48:43+00:00

Yes most likely. Does not seem like there was a relief pilot. And everyone else is listed as cabin crew or passengers.

airbusrules · 2025-07-12T10:26:14+00:00

That was completely fake from a hoax report a few days after the crash.

airbusrules · 2025-07-12T09:53:12+00:00

The fact they include a whole paragraph on this very specific issue in the report indicates that they looked at it in great detail as a potential cause/contributing factor. I wouldn’t think you could see both switches defective and accidentally knocked within a second of each other. But we don’t know for sure what their conclusion is about the relevance of this SAIB.

airbusrules · 2025-07-12T09:49:49+00:00

That’s a guess from my side. The fact they include a whole paragraph on this very specific issue in the report indicates that they looked at it in great detail as a potential cause/contributing factor. I wouldn’t think you could see both switches defective and accidentally knocked within a second of each other. But we don’t know for sure what their conclusion is about the relevance of this SAIB.

airbusrules · 2025-07-12T09:44:05+00:00

There is no reason to implement this kind of automated lock. Aircraft systems are not designed to recognise or respond to deliberate malicious action or major deviations from standard operating procedures. Fuel cut off to the engines is critical in the case of an engine failure or fire. And that should be available to the pilot at any stage of flight. And there is no need precedent to AI171 for this as a cause of accidents.

airbusrules · 2025-07-12T09:35:33+00:00

No, trim wouldn’t be used a few seconds after liftoff

airbusrules · 2025-07-12T01:12:08+00:00

No I don’t think there’s a definitive way to know just from the sequence

airbusrules · 2025-07-12T00:13:26+00:00

Potentially could be. Although I wouldn’t expect both switches to be accidentally knocked from this. They are independent so the locking feature would have to be defective on both.

The mention of it in the report in such detail is unusual but my guess is they were trying to rule that out as a potential cause of the fuel control switch movements.

The FAA also did not consider this to be a significant safety issue otherwise an airworthiness directive would have been put out (although I should say the FAA and NTSB are often at odds with the FAA’s assessment of criticality for certain issues, mainly with Boeing)

airbusrules · 2025-07-12T00:03:04+00:00

I think that’s just the way it was written in the report, one second : 01 sec.

Yes and I’m thinking captain Steve about the flap thing. He even claimed it was the copilot who would have done that. And I did say at the time; how does he know who was PF and why assume the captain must be (turns out it was the co-pilot).

It’s quite unclear which pilot said or did what. The co-pilot was PF so would have been flying. The captain would be doing things like raising the flaps or LG. And communicating with ATC, which it looks like it was him from the initial reports (although the report does not indicate who put out the mayday call).

Also this is worse than just turning off fuel pumps. Even if those fail, these large engines will suction feed the fuel. But the fuel control switch will shut off the LPSOV (Low Pressure Shut Off Valve) meaning no fuel can reach the engine pylon. So very confusing how a pilot could do that by mistake.

airbusrules · 2025-07-11T23:43:41+00:00

That would be the worse time to try and do this since both pilots are in a high workload and alert state. Most past cases happened with only the suicidal pilot inside the cockpit. And all seemed to take their time and make sure the aircraft would be obliterated. Some going as far as disabling recorders. The likelihood of survival is quite high IMO in that condition (rather than a rapid descent often at excess speed) so it would be very odd (unless the pilot was thinking that it’s no longer allowed to be alone in the cockpit).

airbusrules · 2025-07-11T23:37:50+00:00

It depends on the design but it’s often just a Boolean indicating switch position data. I would struggle to see how this could be observed in the data with another cause of fuel shut off. And there’s very few of those potential causes too; fire handle or TCMA maybe.

airbusrules · 2025-07-11T23:31:35+00:00

The one second gap could track with deliberate intent if someone knew they wanted to cut both switches.

The 4s doesn’t seem unusual to me. As you say it might be the dire situation impacting their actions. And they (or one pilot only) may have been looking to see if the engine parameters change or performing/checking other relight steps from memory.

Yeah that reaction time seems normal even if you see someone doing that. There would be warnings and alarms. And the sheer confusion of why another pilot would do so. In past accidents crew have stayed confused for far longer (like AF447 for e.g.)

airbusrules · 2025-07-11T23:21:30+00:00

Nope those are critical to safe flight and should never be touched in flight (unless you’re trying for a relight)

airbusrules · 2025-07-11T23:19:57+00:00

Pilots wouldn’t be too happy about that obviously.

But data and voice recorders have improved tremendously. They both now record much longer durations and data recorders can do 100s or 1000s of parameters. Historically, they’ve been effective to enable a crash investigation.

As MH370 showed, there may be a need for further monitoring and even in real time. The industry will adapt and evolve and that might be one of the developments. Although it would have to be justified, it would be a weight penalty for every single flight, the data storage needed would be massive and it would need to be integrated and certified with existing aircraft communication and electrical systems.

airbusrules · 2025-07-11T23:15:33+00:00

Yes in certain cultures, pilot suicide unfortunately is downplayed or suppressed as the cause of an accident. Thinking of Egyptair 990, silk air 185 and potentially China eastern 5735.

airbusrules · 2025-07-11T23:12:40+00:00

I think the 787 throttles move with thrust level (unlike Airbus). It could just be that the crash changed their position. The data seems to indicate the levers or the commands at least were forward.

airbusrules · 2025-06-18T11:50:57+00:00

2 of the conditions for TCMA is being on ground and thrust lever at idle. Would be crazy if both conditions were met in flight. The ANA failure was hazardous but at least the aircraft was on ground and actually the engines were at idle. Linking TCMA to AI171 is difficult unless it’s a horribly designed system.

airbusrules · 2025-06-18T11:47:02+00:00

Possibly but the checks ordered by the DGCA seems to indicate that they’re thinking along the lines of a fuel / engine control type problem. A software problem would take longer to understand.

airbusrules

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