Re:Boeing 737 MAX crash and the rejection of ridiculous data
by Zak on Wednesday April 10, 2019 @04:08PM
(#19628306)
> Either MCAS is necessary safety equipment, in which case this sounds dangerous, or it isn't, in which case why bother?
The situation is more subtle than that. A simple analogy is that MCAS is like ABS on a car. ABS is not required to drive a car safely and does not activate during normal driving. ABS activating when it should not can cause a crash. Likewise, the intended scenario in which MCAS activates is abnormal and requires a combination of conditions that are unlikely without several errors in judgement by the pilot.
There's another layer though: it's possible to get the 737 MAX into a situation where the standard stall recovery for other 737s, which starts with lowering the nose using the elevator is insufficient. Instead, both the trim and the elevator are required; MCAS does the trim part automatically.
The situation is more subtle than that. A simple analogy is that MCAS is like ABS on a car. ABS is not required to drive a car safely and does not activate during normal driving. ABS activating when it should not can cause a crash. Likewise, the intended scenario in which MCAS activates is abnormal and requires a combination of conditions that are unlikely without several errors in judgement by the pilot.
There's another layer though: it's possible to get the 737 MAX into a situation where the standard stall recovery for other 737s, which starts with lowering the nose using the elevator is insufficient. Instead, both the trim and the elevator are required; MCAS does the trim part automatically.