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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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A B737 air carrier flight crew experienced a cabin altitude warning horn at 34000 ft. They ran the qrc; descended to 24000 ft; and regained control of the cabin with the standby pressure controller.
| Attributes | |
| ACN | 803374 |
| Time | |
| Date | 200809 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : zzz.vortac |
| State Reference | US |
| Altitude | msl single value : 34000 |
| Aircraft 1 | |
| Controlling Facilities | tower : phl.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 65 flight time total : 8500 flight time type : 1800 |
| ASRS Report | 803374 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | aircraft equipment other aircraft equipment : cabin alt warn horn other flight crewb |
| Resolutory Action | flight crew : exited adverse environment flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
After approximately 40 mins of cruise flight; an intermittent takeoff warning horn sounded. Cabin altitude was verified to be at 10200 ft and climbing slowly qrc memory steps were performed (masks; communication). My astute first officer had already selected 'standby' on the cabin pressure controller which caused the cabin altitude to begin to decrease. As a precaution we requested and received clearance to descend to FL240. After a radio conversation with dispatch and maintenance; we continued to ZZZ.
Original NASA ASRS Text
Title: A B737 ACR FLT CREW EXPERIENCED A CABIN ALT WARNING HORN AT 34000 FT. THEY RAN THE QRC; DESCENDED TO 24000 FT; AND REGAINED CONTROL OF THE CABIN WITH THE STANDBY PRESSURE CONTROLLER.
Narrative: AFTER APPROX 40 MINS OF CRUISE FLT; AN INTERMITTENT TKOF WARNING HORN SOUNDED. CABIN ALT WAS VERIFIED TO BE AT 10200 FT AND CLBING SLOWLY QRC MEMORY STEPS WERE PERFORMED (MASKS; COM). MY ASTUTE FO HAD ALREADY SELECTED 'STANDBY' ON THE CABIN PRESSURE CONTROLLER WHICH CAUSED THE CABIN ALT TO BEGIN TO DECREASE. AS A PRECAUTION WE REQUESTED AND RECEIVED CLRNC TO DSND TO FL240. AFTER A RADIO CONVERSATION WITH DISPATCH AND MAINT; WE CONTINUED TO ZZZ.
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.