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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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A B737-500 cabin altitude climbs to 10000 ft at FL390. Crew selection of standby mode regained control. The crew did not descend.
| Attributes | |
| ACN | 792404 |
| Time | |
| Date | 200806 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : zob.artcc |
| State Reference | OH |
| Altitude | msl single value : 37000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-500 |
| 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 : 210 flight time total : 15600 flight time type : 1500 |
| ASRS Report | 792404 |
| Person 2 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
Near the end of cruise at FL370; the cabin altitude warning horn sounded. We donned our oxygen masks and established communications. On pressurization panel I saw cabin climbing at approximately 350 FPM with a cabin altitude about 10000 ft. I selected high flow on both packs; but no change in cabin climb rate. No door lights or other indications on overhead panel. Switched to standby mode (not manual AC/dc) and cabin started to descend at selected rate. At some point I had requested a lower altitude with ATC. Warning horn sounded for 3-5 mins till cabin descended below 10000 ft. After warning horn ceased; we stowed oxygen masks and continued to destination in standby mode.
Original NASA ASRS Text
Title: A B737-500 CABIN ALT CLBS TO 10000 FT AT FL390. CREW SELECTION OF STANDBY MODE REGAINED CONTROL. THE CREW DID NOT DSND.
Narrative: NEAR THE END OF CRUISE AT FL370; THE CABIN ALT WARNING HORN SOUNDED. WE DONNED OUR OXYGEN MASKS AND ESTABLISHED COMS. ON PRESSURIZATION PANEL I SAW CABIN CLBING AT APPROX 350 FPM WITH A CABIN ALT ABOUT 10000 FT. I SELECTED HIGH FLOW ON BOTH PACKS; BUT NO CHANGE IN CABIN CLB RATE. NO DOOR LIGHTS OR OTHER INDICATIONS ON OVERHEAD PANEL. SWITCHED TO STANDBY MODE (NOT MANUAL AC/DC) AND CABIN STARTED TO DSND AT SELECTED RATE. AT SOME POINT I HAD REQUESTED A LOWER ALT WITH ATC. WARNING HORN SOUNDED FOR 3-5 MINS TILL CABIN DSNDED BELOW 10000 FT. AFTER WARNING HORN CEASED; WE STOWED OXYGEN MASKS AND CONTINUED TO DEST IN STANDBY MODE.
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.