Originally Posted by
FCeng84
1. Pilot makes a manual trim command. (MCAS will not re-activate until there have been 5 continuous seconds without pilot trim command.)
Talk of MCAS running the stabilizer for 10 seconds, pausing for 5 seconds, and then running it again repeatedly without pilot trim input are patently incorrect.
Actually, this 'talk' is perfectly correct. When the MCAS system is activated erroneously, the pilot will inevitably make a trim input. And if your trim input is insufficient to counter the MCAS input, as was the case on the Indonesian, you rapidly end up with full nose down trim.
And I have to ask again, because nobody has answered - why would anyone invent a system that gives full nose-down trim? It goes against all aviation history and procedures. Remember the old adage - NEVER FLY WITH THE TRIMMER. And yet here is Boeing effectively using the trimmer as a primary flight control - deliberately placing the aircraft out of trim, instead of keeping it in trim.
That is why all other aircraft have stick-pushers, so you fly the stall with the primary flight controls, not the trimmer. The difference? Assisting the stall with the trimmer leaves you out of trim for the subsequent dive - with 60 kg of pressure on the stick, and 60 turns of the trim before you get back to something that is flyable. Conversely, when a stick pusher relents, you are still in trim, and can recover and fly away with ease. So why did Boeing chose such an absurd system for the 737-Max? Are Boeing really penny-pinching to such a degree? They should have taken a leaf out of the British Midland book - quote: "if you think safety is expensive, try having an accident..."
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