Narrative:

The flight was dispatched with both cockpit and cabin automatic temperature controls inoperative, and these system were placed on MEL. This resulted in the use of manual temperature controls in order to maintain the temperature in the aircraft. The flight was proceeding direct to ywt en route to cyul. Passing through FL280, climbing to FL290, the aircraft cabin began to heat up, followed by an automatic shutdown of the aircraft air cycle machines. Both system pressure gauges indicated zero pressure. No caution lights illuminated to indicate that there was a high temperature in the air conditioning system. The cabin altitude began to climb and the aircraft began to depressurize. Cabin temperature was noted at about 90 degrees. The crew began an emergency descent to 10000 ft. ATC was advised of the situation, and descent clearance was received. The PNF then proceeded to perform the aircraft's cabin pressure loss/rapid descent checklist. The cabin altitude reached approximately 16000 ft and subsequently the oxygen masks automatically deployed and most of the oxygen generators began producing oxygen. The flight attendants then reported a strong odor and 'smoke' coming from the areas around the oxygen door access panels. The PNF then proceeded to perform the air conditioning smoke/in-flight checklist. The flight crew then determined that there was no smoke or fire coming from the air conditioning system, and that the apparent smoke was a result of condensation, heat, and a strong odor emanating from the oxygen generators, after landing, the lead flight attendant reported that some of the oxygen generators malfunctioned and did not produce oxygen. The PF coordinated with ATC for immediate descent into cyyz and the aircraft landed safely. The aircraft was taxied to the gate where the passenger deplaned without injury or damage to the aircraft. Supplemental information from acn 509468: elected to taxi to gate and deplane passenger immediately. We suspect the air conditioning system automatically shut down due to overheating and caused the pressurization loss. We elected not to squawk 7700 or declare an emergency with ATC (toronto center). We elected not to have emergency equipment and fire trucks on landing as we did not see any reason for an emergency or delaying the gate arrival to get passenger off the airplane. In retrospect, we should have squawked 7700, declared an emergency, and had arff meet us on the ground to inspect the aircraft.

Related reports:

Google
 

Original NASA ASRS Text

Title: A DC9-50 ACFT LOSES ITS CABIN PRESSURE DURING AN OVERHEAT ON A MANUALLY RUN TEMP CONTROLLER AND LANDS AT CYYZ, ON.

Narrative: THE FLT WAS DISPATCHED WITH BOTH COCKPIT AND CABIN AUTOMATIC TEMP CTLS INOP, AND THESE SYS WERE PLACED ON MEL. THIS RESULTED IN THE USE OF MANUAL TEMP CTLS IN ORDER TO MAINTAIN THE TEMP IN THE ACFT. THE FLT WAS PROCEEDING DIRECT TO YWT ENRTE TO CYUL. PASSING THROUGH FL280, CLBING TO FL290, THE ACFT CABIN BEGAN TO HEAT UP, FOLLOWED BY AN AUTOMATIC SHUTDOWN OF THE ACFT AIR CYCLE MACHINES. BOTH SYS PRESSURE GAUGES INDICATED ZERO PRESSURE. NO CAUTION LIGHTS ILLUMINATED TO INDICATE THAT THERE WAS A HIGH TEMP IN THE AIR CONDITIONING SYS. THE CABIN ALT BEGAN TO CLB AND THE ACFT BEGAN TO DEPRESSURIZE. CABIN TEMP WAS NOTED AT ABOUT 90 DEGS. THE CREW BEGAN AN EMER DSCNT TO 10000 FT. ATC WAS ADVISED OF THE SIT, AND DSCNT CLRNC WAS RECEIVED. THE PNF THEN PROCEEDED TO PERFORM THE ACFT'S CABIN PRESSURE LOSS/RAPID DSCNT CHKLIST. THE CABIN ALT REACHED APPROX 16000 FT AND SUBSEQUENTLY THE OXYGEN MASKS AUTOMATICALLY DEPLOYED AND MOST OF THE OXYGEN GENERATORS BEGAN PRODUCING OXYGEN. THE FLT ATTENDANTS THEN RPTED A STRONG ODOR AND 'SMOKE' COMING FROM THE AREAS AROUND THE OXYGEN DOOR ACCESS PANELS. THE PNF THEN PROCEEDED TO PERFORM THE AIR CONDITIONING SMOKE/INFLT CHKLIST. THE FLC THEN DETERMINED THAT THERE WAS NO SMOKE OR FIRE COMING FROM THE AIR CONDITIONING SYS, AND THAT THE APPARENT SMOKE WAS A RESULT OF CONDENSATION, HEAT, AND A STRONG ODOR EMANATING FROM THE OXYGEN GENERATORS, AFTER LNDG, THE LEAD FLT ATTENDANT RPTED THAT SOME OF THE OXYGEN GENERATORS MALFUNCTIONED AND DID NOT PRODUCE OXYGEN. THE PF COORDINATED WITH ATC FOR IMMEDIATE DSCNT INTO CYYZ AND THE ACFT LANDED SAFELY. THE ACFT WAS TAXIED TO THE GATE WHERE THE PAX DEPLANED WITHOUT INJURY OR DAMAGE TO THE ACFT. SUPPLEMENTAL INFO FROM ACN 509468: ELECTED TO TAXI TO GATE AND DEPLANE PAX IMMEDIATELY. WE SUSPECT THE AIR CONDITIONING SYS AUTOMATICALLY SHUT DOWN DUE TO OVERHEATING AND CAUSED THE PRESSURIZATION LOSS. WE ELECTED NOT TO SQUAWK 7700 OR DECLARE AN EMER WITH ATC (TORONTO CTR). WE ELECTED NOT TO HAVE EMER EQUIP AND FIRE TRUCKS ON LNDG AS WE DID NOT SEE ANY REASON FOR AN EMER OR DELAYING THE GATE ARR TO GET PAX OFF THE AIRPLANE. IN RETROSPECT, WE SHOULD HAVE SQUAWKED 7700, DECLARED AN EMER, AND HAD ARFF MEET US ON THE GND TO INSPECT THE ACFT.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.