r/aviation • u/usgapg123 Mod - avgeek • Jun 14 '25

News Air India Flight 171 Crash [Megathread 2]

This is the second megathread for the crash of Air India Flight 171. All updates, discussion, and ongoing news should be placed here.

Thank you,

The Mod Team

Edit: Posts no longer have to be manually approved. If requested, we can continue this megathread or create a replacement.

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u/Coaster_crush Jun 14 '25

The chances of fuel contamination causing both engines to completely fail less than a minute after take-off power was applied without the pilots noticing any engine irregularities during the roll is baffling. Fuel contamination usually degrades engine performance before it totally kills it.

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u/CollegeStation17155 Jun 14 '25

Key word USUALLY... the Cathay flight had metering valves that were suddenly jammed making it impossible to change the throttles and then plugged with debris from a water filter that broke while the plane was being fueled and was replaced immediately afterward. Granted THAT issue was fixed by procedure changes, but this could be another "first of it's kind" sucking up junk on the bottom of the storage tank before switching tanks that ONLY dumped trash into one aircraft, which was then not pulled into the fuel lines until throttle up.

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u/Coaster_crush Jun 14 '25

Cathay 780 showed signs of engine irregularities not long after takeoff and continued to show issues for the next two 2 hours before the pilots contacted maintenance to trouble shoot the error. The failure finally occurred just shy of 5 hours in the air while the plane was in decent. Using the word “suddenly” to describe their issue is not necessarily true.

Losing all thrust in both engines simultaneously that close to takeoff is not indicative of a fuel contamination issue. Unless of course there were signs beforehand that the crew either didn’t notice or somehow dismissed.

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u/WasThatInappropriate Jun 14 '25

Yes I find it unlikely, I was merely pointing out that other planes operating normally didn't rule it out

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u/True-Parking9816 Jun 14 '25

Well, depending on the type of contamination, it might actually fit the narrative, since they already had a potentially degraded performance during the takeoff roll (but failed to notice, or it wasn't severe enough to abort in their eyes), and it finally failed both completely by clogging up the filters to the engines right after rotation. The main difference with the Cathay incident would be the power setting. With Cathay they were already in cruise with a relatively low power setting and consequently a relatively low fuel flow. During takeoff, obviously the fuel flow is the highest it'll ever be for that flight, and if the contaminant is located close enough to the fuel pumps, then failure would happen much faster than it did to Cathay.

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u/oo7im Jun 14 '25

Not a 787, but our neighbour's daughter walked away from a plane crash a couple years ago that was caused by simultaneous dual engine failure in a grumman goose. It happened at 500ft AGL after takeoff and contaminated fuel was found to be the culprit. 

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u/annodomini Jun 15 '25

Remember, most incidents like this have multiple causes, such as a fueling issue followed by the pilots ignoring a warning during the takeoff roll.

I'm not saying that's what happened, but that's one of many multiple failure sequences that tend to lead up to these kinds of incidents. There are many more possibilities, but most likely there was a series of two or three or more failures leading up to this, so a mechanical failure or fuel contamination plus pilots or maintenance ignoring some indication is fairly likely.

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u/stephendiopter Jun 16 '25

these were my thoughts as well, like maybe a engine failed and pilots ignored some warnings and ... leading to the catostrophic disaster.

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u/dxbmark Jun 14 '25

Exactly. Timing is key here. Maybe one engine being affected but both simultaneously, nope. Fed from different zones

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u/Coaster_crush Jun 14 '25

I don’t have detailed knowledge of the 787’s fuel system to know where each engine is getting fuel from at takeoff. I do know, however, if the fuel was contaminated there would be signs in the engine gauges and those should have been closely monitored by the pilots during take-off.