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B737-300 flight crew reports cabin altitude warning horn at FL300 and initiates descent before control is regained in manual. Flight continues to destination using a single pack.
| Attributes | |
| ACN | 765564 |
| Time | |
| Date | 200712 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : zzz.airport |
| State Reference | US |
| Altitude | msl single value : 30000 |
| Environment | |
| Flight Conditions | VMC |
| Aircraft 1 | |
| Controlling Facilities | artcc : zzz.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| 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 : 240 flight time total : 12500 flight time type : 3300 |
| ASRS Report | 765564 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 200 flight time total : 9000 flight time type : 500 |
| ASRS Report | 765565 |
| Events | |
| Anomaly | aircraft equipment problem : less severe |
| Independent Detector | aircraft equipment other aircraft equipment : cabin alt warning horn other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : overcame equipment problem |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
While in level cruise at FL300; the first officer and I noticed a beeping noise that we did not recognize. We each thought the other's cell phone alarm had sounded. As we searched for the cause of the sound; I began to think it might be the equipment cooling horn and looked to the equipment cooling lights on the overhead. About the same time; as I was looking at the equipment cooling lights; the first officer and myself both saw the cabin altitude needle indicating above 10000 ft. We immediately donned our oxygen masks. I took control of the aircraft and radios while the first officer ran the qrc for loss of cabin altitude. I coordination a descent and started down. The first officer regained control of the cabin altitude and we leveled at 16000 ft MSL. After talking with both our dispatch and maintenance; we decided that we could control the cabin with 1 pack and the pressure controller in standby. We climbed to FL240 and advised ATC that we were minimum fuel. We continued to ZZZ and landed without incident.
Original NASA ASRS Text
Title: B737-300 FLT CREW REPORTS CABIN ALT WARNING HORN AT FL300 AND INITIATES DESCENT BEFORE CONTROL IS REGAINED IN MANUAL. FLIGHT CONTINUES TO DESTINATION USING A SINGLE PACK.
Narrative: WHILE IN LEVEL CRUISE AT FL300; THE FO AND I NOTICED A BEEPING NOISE THAT WE DID NOT RECOGNIZE. WE EACH THOUGHT THE OTHER'S CELL PHONE ALARM HAD SOUNDED. AS WE SEARCHED FOR THE CAUSE OF THE SOUND; I BEGAN TO THINK IT MIGHT BE THE EQUIP COOLING HORN AND LOOKED TO THE EQUIP COOLING LIGHTS ON THE OVERHEAD. ABOUT THE SAME TIME; AS I WAS LOOKING AT THE EQUIP COOLING LIGHTS; THE FO AND MYSELF BOTH SAW THE CABIN ALT NEEDLE INDICATING ABOVE 10000 FT. WE IMMEDIATELY DONNED OUR OXYGEN MASKS. I TOOK CTL OF THE ACFT AND RADIOS WHILE THE FO RAN THE QRC FOR LOSS OF CABIN ALT. I COORD A DSCNT AND STARTED DOWN. THE FO REGAINED CTL OF THE CABIN ALT AND WE LEVELED AT 16000 FT MSL. AFTER TALKING WITH BOTH OUR DISPATCH AND MAINT; WE DECIDED THAT WE COULD CTL THE CABIN WITH 1 PACK AND THE PRESSURE CONTROLLER IN STANDBY. WE CLBED TO FL240 AND ADVISED ATC THAT WE WERE MINIMUM FUEL. WE CONTINUED TO ZZZ AND LANDED WITHOUT INCIDENT.
Data retrieved from NASA's ASRS site as of January 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.