From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM autolearn=unavailable autolearn_force=no version=3.4.4 X-Received: by 2002:a24:c455:: with SMTP id v82mr5341978itf.143.1555720184354; Fri, 19 Apr 2019 17:29:44 -0700 (PDT) X-Received: by 2002:a9d:2c28:: with SMTP id f37mr3683676otb.126.1555720184056; Fri, 19 Apr 2019 17:29:44 -0700 (PDT) Path: eternal-september.org!reader01.eternal-september.org!feeder.eternal-september.org!news.gegeweb.eu!gegeweb.org!usenet-fr.net!proxad.net!feeder1-2.proxad.net!209.85.166.215.MISMATCH!b2no198468itd.0!news-out.google.com!w17ni228itb.0!nntp.google.com!136no199129itk.0!postnews.google.com!glegroupsg2000goo.googlegroups.com!not-for-mail Newsgroups: comp.lang.ada Date: Fri, 19 Apr 2019 17:29:43 -0700 (PDT) In-Reply-To: Complaints-To: groups-abuse@google.com Injection-Info: glegroupsg2000goo.googlegroups.com; posting-host=113.172.131.50; posting-account=swBhQwoAAAASyh-mRsC176VDTWaaVHF2 NNTP-Posting-Host: 113.172.131.50 References: <8736mwi257.fsf@nightsong.com> <2590d3d8-5f91-4f59-897e-e0c9b7e1b5ca@googlegroups.com> <5f483f72-9213-4c63-b3f9-7150fc4e455f@googlegroups.com> <03d33940-85e9-4fc9-9f2b-2b43f2cfd6af@googlegroups.com> <47a71ba7-38cb-426b-8dad-564f08afbcb2@googlegroups.com> <70d7f427-ddce-4ec0-aba3-99edab0780bc@googlegroups.com> User-Agent: G2/1.0 MIME-Version: 1.0 Message-ID: <53057338-e2a8-4162-9475-f1f5588b11c1@googlegroups.com> Subject: Re: Boeing 737 and 737 MAX software From: tranngocduong@gmail.com Injection-Date: Sat, 20 Apr 2019 00:29:44 +0000 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Xref: reader01.eternal-september.org comp.lang.ada:56168 Date: 2019-04-19T17:29:43-07:00 List-Id: On Friday, April 19, 2019 at 1:20:21 AM UTC+7, Niklas Holsti wrote: > ... > manual correction of the elevation trim=20 > becomes impossibly hard when the MCAS-commanded large "dive" trim=20 > applies large aerodynamic forces to the trim mechanism. Thus the problem= =20 > was not only in the software process, but also in the controllability of= =20 > the aircraft under anomalies > ... > Niklas Holsti > Tidorum Ltd I know. I've seen a couple of pilots confirming this situtation from simula= tor experiments. Every aircraft is designed so that resuming from anormaly, i.e. returning a= control surface from heavily deflected position to neutral, is easy thanks= to aerodynamic force.=20 In particular, manual correction of the horizontal stabilizer becomes impos= sibly hard because the pilot is deflecting the elevator to the maximum, i.e= . he/she is [unknowingly] generating maximal aerodynamic force which goes _= against_ the manual correction. Aerodynamics is friend, not enemy. Pilots are supposed to use it, not to fi= ght it. In order to return the stabilizer, one have to return the elevator to neutr= al first. True, this maneuvre is not so easy as it sounds. It requires training and h= as became less well-known to pilots in the recent decades. Just like assemb= ly language to programmers. The control stick is like a high-level programm= ing language while the trim wheel is like the assembly language. It is more= powerful and it gives more flexibility. But it requires more knowledge and= responsibility. Nevertheless, it is there, and perfectly usable. That said, I don't think manual controlability is a problem of the 737.