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Aircraft equipment problem. Air carrier loses its pressurization slowly so the flight crew makes a slow descent to 10000 ft.
| Attributes | |
| ACN | 310691 |
| Time | |
| Date | 199507 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : mls |
| State Reference | MT |
| Altitude | msl bound lower : 10000 msl bound upper : 33000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc artcc : zmp |
| Operator | common carrier : air carrier |
| Make Model Name | B727-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise other descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 11000 flight time type : 3000 |
| ASRS Report | 310691 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : overcame equipment problem other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Loss of #2 pack. Pressurization unable to hold cabin so we ended up descending to 10000 ft. Callback conversation with reporter revealed the following information: the reporter said that he was flying a B727-200 between geg and msp when they started to lose their pressurization. The crew had just passed MLS and they had switched to the manual system in an attempt to control the pressure loss. They then decided to descend because the cabin altitude continued to climb. The captain decided after the aircraft was finally leveled at 10000 ft to continue to msp, it had been a slow power on descent, rather than attempt to reach a nearer alternate that was in mountainous terrain. The initial response by the maintenance personnel was that the pressurization controller had failed. The crew changed to another B727-200 and continued their flight sequence.
Original NASA ASRS Text
Title: ACFT EQUIP PROB. ACR LOSES ITS PRESSURIZATION SLOWLY SO THE FLC MAKES A SLOW DSCNT TO 10000 FT.
Narrative: LOSS OF #2 PACK. PRESSURIZATION UNABLE TO HOLD CABIN SO WE ENDED UP DSNDING TO 10000 FT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT HE WAS FLYING A B727-200 BTWN GEG AND MSP WHEN THEY STARTED TO LOSE THEIR PRESSURIZATION. THE CREW HAD JUST PASSED MLS AND THEY HAD SWITCHED TO THE MANUAL SYS IN AN ATTEMPT TO CTL THE PRESSURE LOSS. THEY THEN DECIDED TO DSND BECAUSE THE CABIN ALT CONTINUED TO CLB. THE CAPT DECIDED AFTER THE ACFT WAS FINALLY LEVELED AT 10000 FT TO CONTINUE TO MSP, IT HAD BEEN A SLOW PWR ON DSCNT, RATHER THAN ATTEMPT TO REACH A NEARER ALTERNATE THAT WAS IN MOUNTAINOUS TERRAIN. THE INITIAL RESPONSE BY THE MAINT PERSONNEL WAS THAT THE PRESSURIZATION CTLR HAD FAILED. THE CREW CHANGED TO ANOTHER B727-200 AND CONTINUED THEIR FLT SEQUENCE.
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.