ET crash ADD NBO

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Rwy in Sight
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Re: ET crash ADD NBO

#881 Post by Rwy in Sight » Tue Aug 04, 2020 8:24 pm

Boac wrote:
Tue Aug 04, 2020 9:19 am
Finally the FAA have coughed up the requirements for the Max FCS after all the testing. https://www.faa.gov/news/media/attachme ... 8-3-20.pdf.

What puzzles me greatly is that it would appear that the 'isolation' of the MCAS system after a 'failure' still enables uninterupted continuation of the flight? If the dreaded MCAS was so essential to enable certification, why does removal of it from the FCS not constitute a 'land at nearest suitable'??

Page 13 of 36 says
" To assist the flightcrew in properly responding to such an occurrence, a non-normal checklist, called the Speed Trim Fail checklist, would be added to the AFM. This checklist would be used when the STS and MCAS functions are inoperative, and inform the flightcrew to continue normal operation. It would also note that the STS will not provide horizontal stabilizer trim inputs when the airplane deviates from its trimmed airspeed."

So, if it is 'carry on regardless', what was all the fuss about? If it is 'extra training required for crews' why could that not have been done at the beginning by the FAA?
Blow the comment away, but my understanding is that MCAS is associated with /needed on take off and initial climb - to if it becomes unavailable at a later part of the flight then as it is not needed it doesn't impact the continuation decision. Obviously being a SLF I am probably miles off.

The training issue might have something to do with the agreement Boeing has with Southwest (I seem to remember a considerable amount of money to be paid to Southwest if additional training was required for MAX). As the situation turns out this amount is miniscule in comparison to what Boeing has to pay to sort out that mess.

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Re: ET crash ADD NBO

#882 Post by Boac » Tue Aug 04, 2020 8:57 pm

"MCAS is associated with /needed on take off and initial climb " Not so.

The comment on 'training' was directed at the FAA not Boeing

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Re: ET crash ADD NBO

#883 Post by Rwy in Sight » Tue Aug 04, 2020 9:11 pm

Thanks for both corrections.

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Re: ET crash ADD NBO

#884 Post by Boac » Tue Aug 04, 2020 9:26 pm

More time to answer! Apols for brevity.

MCAS was reportedly 'needed' because the stick force for pitch change became 'too light' as the stalling angle was approached. This could happen at any stage of flight - slow speed and/or manoeuvre.

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Re: ET crash ADD NBO

#885 Post by Rwy in Sight » Tue Aug 04, 2020 9:37 pm

For some reason I have connected the MAX issues with too much lift produced by the stronger more forward positioned engines hence I have connected with higher thrust settings on take off and initial climb. Obviously a go around can create the issues you mention.

I am wiser now..

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Re: ET crash ADD NBO

#886 Post by Boac » Wed Aug 05, 2020 7:25 am

RiS wrote:too much lift produced by the stronger more forward positioned engines
you are indeed right in a way. It is said that the 'lift' produced by the more-forward engine nacelles of the MAX increases the aerodynamic pitch-up force at higher angles of attack.

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Re: ET crash ADD NBO

#887 Post by Rwy in Sight » Wed Aug 05, 2020 10:02 am

I would keep that in mind:
This could happen at any stage of flight - slow speed and/or manoeuvre.

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