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Old 4th August 2011 | 23:26
  #24 (permalink)  
john_tullamarine
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: ATPL
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In regards to a real time adventure

Pressurisation schedule monitoring and pilot control is a standard requirement. It should only be a problem requiring extra pilot management if the

(a) system is not operating correctly or if the

(b) aircraft is descending much more rapidly than normal or to an high aerodrome (in which case, the crew should have reset the rate demand to address the problem)

Three end situations -

(a) the aircraft is still pressurised at landing.

The situation arises if the pressurisation system is mishandled. If the aerodrome is above SL then the controller demands must be adjusted to meet the landing diff limit requirements (typically no diff or, for some aircraft, there may be a small residual diff permitted for landing).

Depending on the aircraft, if it lands pressurised, one would normally expect automatic cabin pressurisation dump on touchdown - the occupants would detect that readily via the eardrums.

If the aircraft, for some reason, were still slightly pressurised at the gate, then the doors ought not to be able to be opened. If the crew noticed this and dumped pressure, again the ears would tell the story.

(b) aircraft on schedule at landing - normal situation

(c) aircraft catches the cabin on descent - aircraft becomes unpressurised ahead of schedule expectation and either the crew adjusts aircraft rate of descent or eardrums are uncomfortable
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