MD-83
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Human-Machine Interface; Communication Breakdown
Aircraft Equipment Problem Critical
Flight Crew Returned To Gate; Flight Crew Returned To Departure Airport; General Physical Injury / Incapacitation; General Declared Emergency
Aircraft; Procedure
During the initial climb we were cleared on course and to maintain 280 KTS. Cabin altitude and pressure differential were normal through FL180. Passing FL200 the cabin altitude light illuminated. The cabin altitude then indicated 9;500 FT.We declared an emergency and initiated an emergency descent to 10;000 MSL. We conducted associated checklists and the cabin altitude did not get above 9;500 FT. We leveled at 10;000; and were later cleared to 6;000 FT and given a turn to intercept the localizer for the ILS 25R at our departure airport. We flew the ILS to an uneventful overweight landing at 150;500 LBS and with negligible vertical speed at touchdown. We rolled out long and applied reverse thrust and minimum necessary breaking. During the parking checklist we kept the cabin doors closed due to residual [negative] cabin pressure. I kept the flight attendants and ground personnel away from the cabin doors until the cabin pressure reached air field elevation. While the cabin pressure slowly bled down ground power was plugged in. Shortly after the ground electric was plugged in the cabin pressure dumped and one passenger ruptured her ear drum(s). Operations were notified and CFR sent an ambulance to assist. The passenger; CFR personnel and an accompanying agent were gone before our post flight checks were completed.While I was making logbook entries several Maintenance Personnel swarmed the aircraft. Maintenance advised both pressurization controllers had failed and that the aircraft had an extensive history of pressurization problems.
If it is true that this aircraft had a long history of pressurization problems; it is possible this event could have been avoided with a more thorough investigation of the cause of these problems. I feel the Captain handled this situation perfectly and should be commended for his efforts.
Upon discovery of rapidly rising and uncontrollable cabin altitude; an MD-80 flight crew declared an emergency; descended to 10;000 MSL and returned to their departure airport where the cabin retained significant negative pressure for a period of time until it dumped explosively damaging the ear drums of at least one passenger.