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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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A B737-800 in climb at 12000 ft is alerted by the cabin attendant altitude warning horn. Made immediate descent but oxygen masks deployed. Caused by engine bleed switches off.
| Attributes | |
| ACN | 530028 |
| Time | |
| Date | 200111 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 11000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc tower : teb.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737-800 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | departure : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air taxi |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 115 flight time total : 4200 flight time type : 100 |
| ASRS Report | 530028 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 180 flight time total : 13000 flight time type : 180 |
| ASRS Report | 530004 |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : published procedure other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : cabin alt warning horn other flight crewa other flight crewb |
| Resolutory Action | flight crew : became reoriented other |
| Consequence | other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Flight ZZZ-ZZZ1 11/tue/01 XA01Z. This was continuation through flight on ZZZ1 from ZZZ3 during climb out altitude warning horn came on passing through 11000 ft. Rate of climb was 4000 FPM. Cabin attendant altitude indication was approximately 1200 ft. Leveloff and descent were begun immediately (from approximately 1500 ft). During descent to 10000 ft engine bleed valves were found to be in the off position. Switches were immediately placed on and pressure was re-established, but not before cabin attendant altitude caught up with aircraft altitude and caused deployment of the passenger oxygen system. There was no rapid decompression or excessive maneuvering of the aircraft as an emergency situation did not exist at this time. At no time was an emergency declared or request assist. However the problem arose. Improper switch position or placement of the start.
Original NASA ASRS Text
Title: A B737-800 IN CLIMB AT 12000 FT IS ALERTED BY THE CAB ALT WARNING HORN. MADE IMMEDIATE DSCNT BUT OXYGEN MASKS DEPLOYED. CAUSED BY ENG BLEED SWITCHES OFF.
Narrative: FLT ZZZ-ZZZ1 11/TUE/01 XA01Z. THIS WAS CONTINUATION THROUGH FLT ON ZZZ1 FROM ZZZ3 DURING CLIMB OUT ALT WARNING HORN CAME ON PASSING THROUGH 11000 FT. RATE OF CLIMB WAS 4000 FPM. CAB ALT INDICATION WAS APPROX 1200 FT. LEVELOFF AND DSCNT WERE BEGUN IMMEDIATELY (FROM APPROX 1500 FT). DURING DSCNT TO 10000 FT ENG BLEED VALVES WERE FOUND TO BE IN THE OFF POS. SWITCHES WERE IMMEDIATELY PLACED ON AND PRESSURE WAS RE-ESTABLISHED, BUT NOT BEFORE CAB ALT CAUGHT UP WITH ACFT ALT AND CAUSED DEPLOYMENT OF THE PAX OXYGEN SYS. THERE WAS NO RAPID DECOMPRESSION OR EXCESSIVE MANEUVERING OF THE ACFT AS AN EMER SIT DID NOT EXIST AT THIS TIME. AT NO TIME WAS AN EMER DECLARED OR REQUEST ASSIST. HOWEVER THE PROB AROSE. IMPROPER SWITCH POS OR PLACEMENT OF THE START.
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.