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I'm disappointed that MCAS is still being made primarily about stall avoidance and the idea that a stall means good chance (let alone certain chance) of a crash
by cmurf 8y ago
I'm disappointed that MCAS is still being made primarily about stall avoidance and the idea that a stall means good chance (let alone certain chance) of a crash. A pilot is required to understand and demostrate competency in approach to stall, full stall, and stall recovery for category/class rating and also for type rating.
The purpose of MCAS is to moderate the pitch up due to the aerodynamic lift the new nacelles produce in high angles of attack. But it did so with such aggression that it made it possible, perhaps even likely, that it would result in sufficient mistrim and high airspeed as to make it difficult to correct in a low altitude scenario until it was too late. It was a one size fits all correction, and it was abrupt, regardless of airspeed, which is rather significantly a problem at high airspeeds that would cause a problem even if high angle of attack were true.
The graphic also ignores that MCAS accepts absurd angle of attack values as actionable. In the Ethiopian Airlines case, 75 degrees is a nonsense value, there's no point in correcting for it.
In effect, they made it both too simple, and deadly.
- Doxin 8y agoThe problem with the 737 MAX is that it can get into a stall from which you cannot recover. It doesn't behave the same as a regular 737 at all, which in turn means that the actions needed to prevent a stall are wildly different. In a regular 737 you apply more throttle in a stall to get more lift. In a 737 MAX applying more throttle will point the plane even more nose-up worsening an already bad situation.
- cmurf 8y agoDo you have a citation for this? Getting into an unrecoverable stall is a violation of FAR 25.203(c).
- Doxin 8y agoI should've been more specific: unrecoverable using the old procedures And I'll be honest I'm rather an armchair expert here, so I don't have any citations to back up above claims.