PPRuNe Forums - View Single Post - Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed
Old 14th Mar 2019, 18:21
  #181 (permalink)  
canyonblue737
 
Join Date: Feb 2005
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Originally Posted by Vilters
I don't want to be in the shoe's of the Boeing guy who is going to sign off on this.

If they think they can fix what is clearly a hardware/sensor issue with an MCAS software update must live in dreamland.

But , tja, we live in an IT is GOD period.

This is clearly a HARDWARE issue, the software is secondary.
everything below is about LION AIR:

1. i see no evidence you can't disable MCAS with stab trim cutout. this is the bottom line fix that works even when all else fails. i have yet to see it won't work or didn't work in any of these accidents, it just wasn't tried.
2. i see no evidence that MCAS didn't perform *as designed* in response to an inaccurate indication of a stall based on a flawed AOA sensor. that's a software response to a hardware failure.
3. Boeing has already stated the coming fix to the software will: 1) have MCAS compare both AOA sensors and require them to match prior to any application of trim 2) have a visual alert appear to the pilots showing the MCAS application and 3) disable the ability of MCAS to apply more than a certain amount of total trim, a value which can be overcome by pilots with yoke force. that seems comprehensive in terms of a fix that would have prevented the lion air accident from happening.

i see ZERO reason the MCAS issue wouldn't be resolved by the coming fix even for pilots who don't understand the proper use of the stab trim cutout switches but of course we have to wait and see what the evidence shows with this weeks tradgedy.

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