The aft end of the interior of NASA's Boeing 747Shuttle Carrier Aircraft. The aft pressure bulkhead is the white circular component, and its web-like structure led a NASA technician with a sense of humor to add a large stuffed spider to the decor.
The aft pressure bulkhead or rear pressure bulkhead is a component of all large commercial aircraft. It is an airtight bulkhead located between the cabin and the tail of the aircraft. Its purpose is to seal the rear of the plane and thus maintain cabin pressure, and as such it is a vital part of the aircraft.
In 1971 British European Airways Flight 706 crashed in Belgium, killing all 63 on board; the cause was determined to be corrosion of the rear pressure bulkhead by fluid contamination, perhaps from the lavatory. The corrosion was not detectable by the inspection techniques at the time.
In 1985 Japan Airlines Flight 123 crashed after a catastrophic failure of the aft pressure bulkhead. The failure occurred due to faulty repair of the bulkhead after a tailstrike seven years earlier, when a single repair patch plate was incorrectly cut in two "to make it fit". Failure of the bulkhead damaged hydraulic pipes passing through. Boeing later calculated that the incorrect installation would be expected to fail after approximately 10,000 pressurizations; the repaired aircraft accomplished 12,318 successful flights before the crash.