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An MD83 flight crew experienced dual pack trip from duct overheat in cruise flight; resulting in loss of pressurization. They descended to a safe altitude and regained control of the packs.
| Attributes | |
| ACN | 812851 |
| Time | |
| Date | 200811 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : dfw.airport |
| State Reference | TX |
| Altitude | msl single value : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zfw.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | MD-80 Series (DC-9-80) Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level ground : maintenance |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 15000 flight time type : 10000 |
| ASRS Report | 812851 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | aircraft equipment other aircraft equipment : pack trip light |
| Resolutory Action | flight crew : overcame equipment problem flight crew : exited adverse environment |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
While in cruise as a maintenance ferry flight; we were having to monitor the air conditioning pack's output temperatures closely. Due to the lack of passenger providing heat; the pack output temperatures were very high as they tried to maintain even a reasonably lukewarm cabin and cockpit temperature. Even though our aircraft duct temperature gauge showed pack temperatures within limits; a duct overtemp trip in both packs must have occurred; resulting in a loss of pressurization input; and a fairly rapid cabin altitude climb. We donned oxygen masks and performed our memory items for rapid depressurization; requesting and getting ATC clearance to FL240; then 11000 ft. Both packs returned to normal operation while passing FL200; and pressurization returned to normal. Since we were already on the arrival to dfw with ample fuel; we continued for a normal landing.
Original NASA ASRS Text
Title: AN MD83 FLIGHT CREW EXPERIENCED DUAL PACK TRIP FROM DUCT OVERHEAT IN CRUISE FLIGHT; RESULTING IN LOSS OF PRESSURIZATION. THEY DESCENDED TO A SAFE ALTITUDE AND REGAINED CONTROL OF THE PACKS.
Narrative: WHILE IN CRUISE AS A MAINT FERRY FLT; WE WERE HAVING TO MONITOR THE AIR CONDITIONING PACK'S OUTPUT TEMPS CLOSELY. DUE TO THE LACK OF PAX PROVIDING HEAT; THE PACK OUTPUT TEMPS WERE VERY HIGH AS THEY TRIED TO MAINTAIN EVEN A REASONABLY LUKEWARM CABIN AND COCKPIT TEMP. EVEN THOUGH OUR ACFT DUCT TEMP GAUGE SHOWED PACK TEMPS WITHIN LIMITS; A DUCT OVERTEMP TRIP IN BOTH PACKS MUST HAVE OCCURRED; RESULTING IN A LOSS OF PRESSURIZATION INPUT; AND A FAIRLY RAPID CABIN ALT CLB. WE DONNED OXYGEN MASKS AND PERFORMED OUR MEMORY ITEMS FOR RAPID DEPRESSURIZATION; REQUESTING AND GETTING ATC CLRNC TO FL240; THEN 11000 FT. BOTH PACKS RETURNED TO NORMAL OP WHILE PASSING FL200; AND PRESSURIZATION RETURNED TO NORMAL. SINCE WE WERE ALREADY ON THE ARR TO DFW WITH AMPLE FUEL; WE CONTINUED FOR A NORMAL LNDG.
Data retrieved from NASA's ASRS site as of May 2009 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.