How to depressurize an aircraft
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Thanks for doing the math, BAe, however, an 8psi diff on the ground seems rather high. That would put the cabin altitude very far below sea level (circa -10,000 feet) even at an airport like Denver (~5,000 MSL).
Last edited by vapilot2004; 8th Jun 2018 at 02:16.
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On the outside of a 747 classic while talking to the engineers in the cockpit after a pressurization check we couldn't open the main entry door even when the cockpit pressure was indicating zero. The butterfly handles wouldn't budge past a certain point, eventually the upper and lower gates opened with a burst of air rushing out.
As said above the negative relief valves are probably the best bet if you don't want to damage the aircraft by punching a hole in it.
Anything other than near zero diff pressure and you better use an axe or considerably larger if you're in a rush.
As said above the negative relief valves are probably the best bet if you don't want to damage the aircraft by punching a hole in it.
Anything other than near zero diff pressure and you better use an axe or considerably larger if you're in a rush.
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Well I thought the scenario was that the system was not working correctly - after all it the system is perfectly serviceable it would have depressurized on landing.
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In practice, it would be fairly difficult for the cabin altitude to be driven that low with a flight deck crew that is present and awake during ground operations, although for this thought exercise, anything is possible and theoretically you are quite right, BAe.
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