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Old 19th Apr 2012, 16:00
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Owain Glyndwr
 
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Machinbird

What assumptions are made in this graph regarding nose down trim performance by the flight control system? What assumptions are made with regard to AOA management by the crew since the flight control system does not manage AOA in Alt law.
None - it is just a performance calculation in which the crew is assumed to apply pitch at a given rate until the desired steady ND value is achieved, and then to fly constant pitch attitude until about 250 kts EAS at which point it is assumed that pitch is reversed at the same rate as going in, unless the S/W boundary is exceeded in which case the pitch rate was backed off to keep inside the limit (this only applied in the 3 deg/sec FL350 case). There is an implicit assumption that since the crew did not have AoA information they couldn't fly to manage it, but they could fly pitch.

Don't look for too much detail in this picture - it isn't there.

They could have still recovered down to ~5000 feet if all went perfectly? What a tragedy
Yes, but can you see anyone passing through FL60 at 10,000 fpm applying 10 deg ND pitch and holding it? This line unfortunately is very theoretical.

Lyman

For instance you have a G demarcation that looks luscious, but can you give some direction as to how it may have felt, indexed with a/s, and ROD?
Since there is no G on the graph I am at a loss how to reply, but the pull-up 'g's were in the range 1.4~1.7

Last edited by Owain Glyndwr; 19th Apr 2012 at 16:05. Reason: additional comment
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