depressurising the cabin from outside
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depressurising the cabin from outside
A/c in short term parking condition, ditching button pressed, cabin technicians connect ground a/c unit, close the doors and cabin is now pressured XD, they cant open the doors from the inside, so they call us up, what we did was turn off and disconnect A/c unit, open avionics vent inlet/outlet then slowly unlatch cargo door as instructed by the engineer.
is there a faster approach to do this or that was all that could be done ?
a/c is A320
is there a faster approach to do this or that was all that could be done ?
a/c is A320
Join Date: Apr 2004
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I would refrain from cargo door opening. Damage to the internal mechanism can occur.
@ Truck2005:
The A320 Fam has a vacuum toilet system. So this trick does not work.
What i would do:
First switch off the external aircondition unit.
If you have persons inside which are not unconsciously, tell them to switch on the battery and press the ditching button.
If no one is on board who can act, open the skin air inlet and outlet valve manually.
The aircraft is not completely airtight, so the pressure will be drop even if you do nothing except removing the air source.
If the delta p is lower then 2 psi the fuselage drain valves open and the pressure will drop faster.
@ Truck2005:
The A320 Fam has a vacuum toilet system. So this trick does not work.
What i would do:
First switch off the external aircondition unit.
If you have persons inside which are not unconsciously, tell them to switch on the battery and press the ditching button.
If no one is on board who can act, open the skin air inlet and outlet valve manually.
The aircraft is not completely airtight, so the pressure will be drop even if you do nothing except removing the air source.
If the delta p is lower then 2 psi the fuselage drain valves open and the pressure will drop faster.
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That's what I would have done. If You're really In a hurry! (Dying person on-board). Then crack the cargo door handle.
Old style door handle - pulling the lever out opens the vent doors only not the door C-latches.
New style cargo door - first 20 degrees of operation opens the vent doors only. further operation disengages the latches.
Old style door handle - pulling the lever out opens the vent doors only not the door C-latches.
New style cargo door - first 20 degrees of operation opens the vent doors only. further operation disengages the latches.
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OK, with an emergency on board i would give a 
to a damaged at the A/C.
But vent doors are also plug type doors. With a high delta p i do not think that the actuating mechanism for the vent door even work.
More likely is than bending of the actuating links.
Removing the fuselage drain valves may help.
Braking a window with a axe?
Cabin maybe, Cockpit not possible.
to a damaged at the A/C.But vent doors are also plug type doors. With a high delta p i do not think that the actuating mechanism for the vent door even work.
More likely is than bending of the actuating links.
Removing the fuselage drain valves may help.
Braking a window with a axe?
Cabin maybe, Cockpit not possible.
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Alright, I'll take a stab....
Open access door 191CB and then push open the check valves at the LP Ground Connection.
et voila .... Cabin pressure returns to ambient in no time.
cod
et voila .... Cabin pressure returns to ambient in no time.
cod
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Be realistic
Come on. Best realistic and be an engineering minded.
In the case of emergency. The best and easy way is exactly what ahmed 88 has stated or IFixPlanes has said " ............ turn off and disconnect A/c unit, open avionics vent inlet/outlet ..................."
Where to find a 3/8 inch allen key to open the drain valves. Push open the air conditioning check valve (flap valve type) would probably chop off your fingers with Delta pressure or a mouthful of dust.
Open the toilet drain??????? on a vacuum system.
Open the vent door on a door.???? Most likely you would be knocked into the air when the door is swung open with some different pressure. Even a 0.01 psi on a door of 70" x 40" would give a total 28 lbs of force.
It takes less than 20 second to wind the small handle of the avionic ventilation inlet/outlet vent valves fully open and it is reachable without a ladder.
The following is from Airbus notes:-
PAX-DOOR OPERATION
Precautions / Warnings
WARNING : Do not operate the door control handles inside or outsite if the
red cabin pressure warning light in the door window is flashing :
In that case there is a cabin overpressure of more than 2.5 mb
( 0.037 psig )
Residual pressure could cause the door to open with a sudden
force and injure persons and / or damage the aircraft.
Do not go near or open pressure sealed doors when the aircraft
is pressurized. If you do you will cause explosive decompression,
kill or injury to persons and cause damage to the aircraft.
Do not open the passenger / crew door if the wind speed is more
than 65 knots.
In the case of emergency. The best and easy way is exactly what ahmed 88 has stated or IFixPlanes has said " ............ turn off and disconnect A/c unit, open avionics vent inlet/outlet ..................."
Where to find a 3/8 inch allen key to open the drain valves. Push open the air conditioning check valve (flap valve type) would probably chop off your fingers with Delta pressure or a mouthful of dust.
Open the toilet drain??????? on a vacuum system.
Open the vent door on a door.???? Most likely you would be knocked into the air when the door is swung open with some different pressure. Even a 0.01 psi on a door of 70" x 40" would give a total 28 lbs of force.
It takes less than 20 second to wind the small handle of the avionic ventilation inlet/outlet vent valves fully open and it is reachable without a ladder.
The following is from Airbus notes:-
PAX-DOOR OPERATION
Precautions / Warnings
WARNING : Do not operate the door control handles inside or outsite if the
red cabin pressure warning light in the door window is flashing :
In that case there is a cabin overpressure of more than 2.5 mb
( 0.037 psig )
Residual pressure could cause the door to open with a sudden
force and injure persons and / or damage the aircraft.
Do not go near or open pressure sealed doors when the aircraft
is pressurized. If you do you will cause explosive decompression,
kill or injury to persons and cause damage to the aircraft.
Do not open the passenger / crew door if the wind speed is more
than 65 knots.
Last edited by Kuchan; 20th Jun 2011 at 18:15.
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We connect external air to all our nightstops, leave the aircraft on ground service, and close the door.
One bright captain last winter pressed the ditching button before leaving the aircraft, without telling or asking anyone. When I had finished the checks, I left, and then the cleaners closed the door.
In the morning, the crew walk down the jetty. The dispatcher says that she can't open the door. The captain sees that the red light is flashing. That can't be right, he says, let me do it. The first officer caught him as the door propelled him across the jetty.
One bright captain last winter pressed the ditching button before leaving the aircraft, without telling or asking anyone. When I had finished the checks, I left, and then the cleaners closed the door.
In the morning, the crew walk down the jetty. The dispatcher says that she can't open the door. The captain sees that the red light is flashing. That can't be right, he says, let me do it. The first officer caught him as the door propelled him across the jetty.
