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The only affected models were 737s with the 766AT613-3D fuel control switch. The bulletin recommended that other models be inspected and any defects reported. I
by ggreer 1y ago
The only affected models were 737s with the 766AT613-3D fuel control switch. The bulletin recommended that other models be inspected and any defects reported. It's unclear if any 787s were discovered to have the issue. Also the preliminary report mentions that the switches were replaced in 2019 and 2023, after the 2018 bulletin.
- deleted 1y ago[deleted]
- rnlkh 1y agohttps://ad.easa.europa.eu/blob/NM-18-33.pdf/SIB_NM-18-33_1 https://ad.easa.europa.eu/blob/NM-18-33.pdf/SIB_NM-18-33_1 Here is the full SAIB on the Boeing fuel control switches. This report lists the part 4TL837-3D as the switch used on 787s, and is the part mentioned in the preliminary report on the accident. The SAIB does single out the part 766AT613-3D, but that's for suggesting a replacement for it as 766AT614-3D. Per the Honeywell catalog for 4TL837-3D, if is a Snap Action toggle switch. The base model doesn't have a locking mechanism, which is available as an option
- lazystar 1y agostill, it at least shows that there's been issues with the locking mechanism in the past. inadvertently bumping something that was assumed to be locked is a simpler theory; i find it hard to believe that a murder suicider would take this route, when the china nosedive option is easier, faster, and has a higher chance of success.
- ggreer 1y agoThe preliminary report says the switches were triggered a second apart, so it would have to have been faulty switches and two inadvertent bumps. That seems unlikely to me.
- somat 1y agoWithin a second apart. If I read the report right. The time resolution of the recorder? And yes, it does sound like it was probably intentional. I would still like to see an engineering review of the switch system. Are they normally open or normally closed, In the end the switch instructs the FADEC to cut the fuel, but where does the wiring go in the meantime? what software is in the path? would the repair done before the flight be in that area?(pilot defect report for message STABS POS XCDR), and perhaps compromised the wires?
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- cosmicgadget 1y agoCutting fuel just after takeoff leaves almost zero time for the other pilot to recover.
- manquer 1y agoit 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 ?
- throwaway48476 1y agoA fully fueled plane crashing in takeoff guarantees a huge fire.
- manquer 1y agoThat 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 .
- bombcar 1y agoIt's interesting to try to imagine a device that would prevent that, without causing more issues. My preliminary idea is a "fuel bladder" for take-off that inflates with enough fuel to get the plane to a recoverable altitude, maybe a few thousand feet?
- sugarpimpdorsey 1y ago> My preliminary idea is a "fuel bladder" for take-off that inflates Will the bladder be marketed by Kramerica Industries?