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Air carrier medium large transport experienced loss of pressurization. Executed emergency descent procedure.
| Attributes | |
| ACN | 138862 |
| Time | |
| Date | 199003 |
| Day | Tue |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : ipl |
| State Reference | CA |
| Altitude | msl bound lower : 35000 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other descent other other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : commercial pilot : atp pilot : instrument pilot : flight engineer |
| Experience | flight time last 90 days : 200 flight time total : 5000 flight time type : 2000 |
| ASRS Report | 138862 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : instrument pilot : flight engineer pilot : commercial |
| Experience | flight time last 90 days : 150 flight time total : 4000 flight time type : 1000 |
| ASRS Report | 138755 |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | aircraft : equipment problem dissipated flight crew : declared emergency flight crew : overcame equipment problem other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
Narrative:
Had rapid depressurization at cruise at FL350 did checklist and made rapid descent to 10000'. Cabin reached 15000' and O2 masks dropped in passenger compartment. Pressurization system began to work again at approximately FL240. Maintenance's theory was differential pressure limits were exceeded when outflow valve stuck and relief valves dumped the cabin pressure. System began working normally after differential pressure was below maximum limits, and drove cabin back down below 10000'. No passenger problems and landing was without incident.
Original NASA ASRS Text
Title: ACR MLG EXPERIENCED LOSS OF PRESSURIZATION. EXECUTED EMERGENCY DESCENT PROC.
Narrative: HAD RAPID DEPRESSURIZATION AT CRUISE AT FL350 DID CHECKLIST AND MADE RAPID DSCNT TO 10000'. CABIN REACHED 15000' AND O2 MASKS DROPPED IN PAX COMPARTMENT. PRESSURIZATION SYSTEM BEGAN TO WORK AGAIN AT APPROX FL240. MAINT'S THEORY WAS DIFFERENTIAL PRESSURE LIMITS WERE EXCEEDED WHEN OUTFLOW VALVE STUCK AND RELIEF VALVES DUMPED THE CABIN PRESSURE. SYSTEM BEGAN WORKING NORMALLY AFTER DIFFERENTIAL PRESSURE WAS BELOW MAX LIMITS, AND DROVE CABIN BACK DOWN BELOW 10000'. NO PAX PROBLEMS AND LNDG WAS WITHOUT INCIDENT.
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.