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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,d923bb34ea827f56 X-Google-Attributes: gid103376,public From: Sam Harbaugh Subject: Re: Ada / Boeing 777 Date: 1996/03/18 Message-ID: <199603181348.IAA08669@bb.iu.net>#1/1 X-Deja-AN: 143657646 sender: Ada programming language x-sender: harbaugh@iu.net comments: Gated by NETNEWS@AUVM.AMERICAN.EDU content-type: text/plain; charset="us-ascii" mime-version: 1.0 newsgroups: comp.lang.ada x-mailer: Windows Eudora Light Version 1.5.2 Date: 1996-03-18T00:00:00+00:00 List-Id: Tim Rowe wrote: >As an example, there was a known fault on one of the Airbus range (which >has been flying total fly-by-wire for *many* years before the 777!) that >meant that when flying a heading of 00 degrees, if the pilot commanded >the aircraft to turn a bit one way, the aircraft could actually turn the >other way. It was turning to the correct heading, but it was going the >359 degree route, not the 1 degree route. Now, there are not many runways >in the world that are close to north-south, but there are a few, and when >that bug showed itself on a final approach I bet the pilots pants turned >brown. Point of order: heading zero is invalid in the user space. north-south runways are marked 36 for 360 degrees, not zero. Pilots and ATC speak of 360 degrees, not zero degrees. I wouldn't suggest that this point has anything to do with the malfunction but maybe, just maybe, if the programmer had a pilot's license he/she would have known this and then maybe, just maybe, he/she would have known to turn in the proper direction. Just maybe, just possibly maybe, if the code was written in a strongly typed language, using human readable names, and a pilot attended a code walkthrough, the pilot would have picked up on type heading_type being from 0..359 instead of 1..360 and started a conversation that would have lead to discovery of the worong way turn. I wonder what language would provide this feature :-) sam harbaugh harbaugh@acusys.com p.s. does this remind you of the "two values for midnight" thread of years ago?