A DK leakdown check is a test that is performed after a C/D check. THe Plane is pressurized to max dif. then the air is turned off and the aircraft is sealed tight as it can be and then allowed to stabilize at sea level. It checks the integrity of the cabin. You would be astonished at how leaky an aircraft actually is. Much of it is by design. The lavs have their own little outflows, the galleys, the e/e bays etc.
Certifications requires it to take a minimum of 90 seconds from 8 PSI to 0 PSI. 3-5 minutes is the norm in the 25 Post C Check test flights that I personally did at my last carrier, and I never saw 10 minutes.
Cheers
Wino
PS. AA is my 7th airline as well, including 3 European ones. It is by FAR the safest operation going. And skydrifter, you may hate the FAA, but try out the british CAA sometime. The FAA has them beat as well.
[This message has been edited by Wino (edited 11 May 2001).]