How the pilots of Lion Air Flight 610 lost control

Re:How the pilots of Lion Air Flight 610 lost control by WalterBright on Thursday December 27, 2018 @12:46AM (#18767637)

What the pilots experienced was indistinguishable from runaway stab trim, and shutting off the stab trim from the switches on the console is the correct response. There's a loud distinctive sound when the trim runs, and the wheels that bracket the console turn, so it's pretty obvious. The previous flight's pilots had indeed done this. The pilots are trained for this. They has 12 minutes to shut off the repeated action of the runaway stab trim.

Additionally, the airplane should have been grounded after the previous flight, as runaway stab trim is a serious problem, until the fault was found and corrected.

Equally badly, the flight crew was probably not informed of what had happened on the previous flight.

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Re:How the pilots of Lion Air Flight 610 lost control by cameldrv on Thursday December 27, 2018 @01:32PM (#18771366)

Well sort of but not quite. When the pilots clicked the trim up switch on the yoke, it disabled the MCAS system for 5 seconds -- i.e. it made the problem go away temporarily. Then MCAS comes right back with more nose down trim. This is not a typical runaway trim situation where it's just continuously rolling in more trim. The pilots had no idea that this system existed or that a "runaway trim" failure could have these characteristics.

Sure, it's easy to say from the ground with what we know now that all they had to do was flip a couple of switches, and that a previous crew managed to land safely. However, the job of an airplane is not to be safe only with quick thinking, above average pilots. If a single sensor failure can present a situation that 99% of pilots will successfully diagnose and recover from, you're looking at multiple crashes per year.

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Re:How the pilots of Lion Air Flight 610 lost control by WalterBright on Thursday December 27, 2018 @04:53PM (#18772942)

The pilots did not need to diagnose the system. It would have been obvious that the trim system was running, and was causing the nose down. The trim cutoff systems are right there on the center console. They dealt with the issue for 12 minutes, lightning reflexes were not necessary.

The NTSB will of course look into the CVR, the pilots' training, background and track record to try to figure out why they did not use the cutoff switches. I'm very curious about that.

Similar types of accidents have occurred in the past and turned out to be CRM (Cockpit Resource Management) issues, where the copilot recognized what was wrong but was intimidated by the pilot into doing nothing.

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Re:How the pilots of Lion Air Flight 610 lost control by lsh123 on Thursday December 27, 2018 @01:47AM (#18767899)

Exactly. While Boeing indeed added a new system, the malfunctions and resolutions matrix didn’t change. Thus Boeing didn’t need to change training and claimed that new planes can be flown without any additional training. It’s hard to fault Boeing here.

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Re:How the pilots of Lion Air Flight 610 lost control by dotancohen on Thursday December 27, 2018 @08:16AM (#18769240)

Are you saying that pilots can transition from a 737 to a 737MAX with no sim time? I thought that they had different instrumentation, at the very least.

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