Originally Posted by
RetiredBA/BY
Your opinion !
Although now retired and only SLF but I have over 10 ,000 hours command time on 73s 75s and 76 s.
I have never flown a Max but have looked at a LOT of documentation re MCAS.
I still cant understand how the Max was certified for operation with just ONE component able to drive the most powerful control surface.
Further , despite current Boeing. philosophy, I would want to know and understand EVERYTHING. about a system, particularly one which could kill me, exactly how it works, how it can fail. and how to deal with it and have seen and practiced operation and failures in the simulator, BEFORE becoming type rated.
Many years ago I was posted to an RAF squadron as a replacement pilot for one killed in the Valiant crash believed to have been caused by a runaway stab. The aircraft were not modified BUT we all went into the sim to practice the recovery procedure as it was found that full elevator could just overcome the stab. Deflection. Boeing please note.
After that experience I absolutely beleive that if MCAS is retained its authority should not be greater than can be overcome be elevator input.
Until the. MAX crashes I had the very highest respect for Boeing aircraft. With the Max MCAS they, to quote a senior retired NTSB. inspector , dropped the ball, bigtime.
I am sure the Max will be returned to service in due course as a very safe aircraft. But in its single A of A Sensor coupled to its MCAS system it should never have been certified.
When I did my 737 conversion at Boeing in Seattle back in 1980 our instructors were adamant that all their aircraft were designed to be flown with ease by any and all of the worlds airline pilots. The Max seems to have beaten four with tragic results.
That is the point though. If you are fighting MCAS with elevator you have already stopped flying the aircraft as MCAS stops when you trim - the button by your left thumb. Of course if you -_don't_ trim then you have already ceded aircraft control especially if you let the speed increase where the stab will always have more authority. But trimming to unload the control column forces should be instinctive, for those pilots for whom that is still the case they will fly the aircraft home.
I suspect that the FMEA showed that a rare AOA failure could cause MCAS to operate despite not being at high AOA but the crew were expected to react by trimming the aircraft. After all who would expect a professional crew to let the aircraft repeatedly trim down and not use the control column trim to put it back in trim? If MCAS operated with uncommanded nose down trim repeatedly after being recovered back to trim as in the Lion Air flights - then the flight crew would be expected to switch the stab trim off as the penultimate Lion Air flight did do. Nobody at Boeing thought that pilots would be saying "no the stab trim cut out switches are
only for _
runaway_ trim and that is
_repeated_ trim". So now the single point of failure - which definitely should not have been there - even with FMEA showing that crews were expected to stop the problem- has been removed the repeated operation in a failure mode has been removed. What has not been removed is that concern about what NNCs are being considered as extremely specific by crews due to the tick box simulator training approach. There are going to be other complex failures (as in rodent eating a cable) that cannot be described in NNCs and where
=Fly the aircraft= is really important
regardless of horns shakers cavalry charges etc etc, and yet we have crews that will not even trim.
As 737 Driver has said this is looking more like a training issue