Certification issues for Emergency descent?
Grandpa Aerotart
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Certification issues for Emergency descent?
Is their any certification issues regarding maximum time allowed for emergency descent from cruise to 14000 feet?
FAR25.8 mentions 2 minutes max exposure for cabin occupants at FL250 and 0 at FL400 but this seems to be a hull integrity standard.
One of my F/Os mentioned 4 minutes but this rings no bells, other than for deciding minimum O2 requirements (Australian CAOs).
Chuck
FAR25.8 mentions 2 minutes max exposure for cabin occupants at FL250 and 0 at FL400 but this seems to be a hull integrity standard.
One of my F/Os mentioned 4 minutes but this rings no bells, other than for deciding minimum O2 requirements (Australian CAOs).
Chuck
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FAR 25.841 Pressurized cabins.
(a) Pressurized cabins and compartments to be occupied must be equipped to provide a cabin pressure altitude of not more than 8,000 feet at the maximum operating altitude of the airplane under normal operating conditions.
(1) If certification for operation above 25,000 feet is requested, the airplane must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of 15,000 feet after any probable failure condition in the pressurization system.
(2) The airplane must be designed so that occupants will not be exposed to a cabin pressure altitude that exceeds the following after decompression from any failure condition not shown to be extremely improbable:
(i) Twenty-five thousand (25,000) feet for more than 2 minutes; or
(ii) Forty thousand (40,000) feet for any duration.
(3) Fuselage structure, engine and system failures are to be considered in evaluating the cabin decompression.
This is the occupant limitations not the structure.
To meet this requirement there is a FM procedure for getting the aircraft down in a hurry (such as DC-8 reversing engines in flight) Biggest problem is obviously getting down quickly within limiting speeds.
From 40,000 you would meet the cabin coming up.
Obviously you have to be able to get down to 25,000 before the cabin pressure has dissapated and then max 2 mins to 15,000
FAR 25.841 Pressurized cabins.
(a) Pressurized cabins and compartments to be occupied must be equipped to provide a cabin pressure altitude of not more than 8,000 feet at the maximum operating altitude of the airplane under normal operating conditions.
(1) If certification for operation above 25,000 feet is requested, the airplane must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of 15,000 feet after any probable failure condition in the pressurization system.
(2) The airplane must be designed so that occupants will not be exposed to a cabin pressure altitude that exceeds the following after decompression from any failure condition not shown to be extremely improbable:
(i) Twenty-five thousand (25,000) feet for more than 2 minutes; or
(ii) Forty thousand (40,000) feet for any duration.
(3) Fuselage structure, engine and system failures are to be considered in evaluating the cabin decompression.
This is the occupant limitations not the structure.
To meet this requirement there is a FM procedure for getting the aircraft down in a hurry (such as DC-8 reversing engines in flight) Biggest problem is obviously getting down quickly within limiting speeds.
From 40,000 you would meet the cabin coming up.
Obviously you have to be able to get down to 25,000 before the cabin pressure has dissapated and then max 2 mins to 15,000
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BIK,
Yes I am sure the is some statistical definition for the two situations.
Which may be forthcoming ?
LU where are you ??
Remember after 99 reds on the roulette table the odds on another red are still 2 to 1 !!!!
Yes I am sure the is some statistical definition for the two situations.
Which may be forthcoming ?
LU where are you ??
Remember after 99 reds on the roulette table the odds on another red are still 2 to 1 !!!!
