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A B727-200 in cruise at FL230 made an emergency descent due to loss of cabin pressure due to the left air conditioning pack failure.
| Attributes | |
| ACN | 435271 |
| Time | |
| Date | 199904 |
| Day | Sun |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | airport : dsm.airport |
| State Reference | IA |
| Altitude | msl single value : 23000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zau.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B727-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Route In Use | enroute airway : j60.airway |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : instrument pilot : commercial pilot : atp |
| Experience | flight time last 90 days : 81 flight time total : 4900 flight time type : 50 |
| ASRS Report | 435271 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | aircraft equipment other aircraft equipment : cabin pressure indicator other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : overcame equipment problem |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
As we were leveling at FL230, heard short beep in cockpit. As we investigated its cause, the altitude warning horn began to sound steadily. Cabin altitude was about 10500 ft and rising at a rate of about 500 FPM. The so observed the outflow valve was closed and recycled the packs. At that time we obtained clearance to descend out of FL230. We commenced descent and the so regained control of the cabin as we began our descent. The masks in the cabin did not deploy and we continued descent, with ATC clearance to 10000 ft. We were able to determine that the right pack would hold cabin pressure, but the left pack would not. The appropriate checklists and procedures were performed as necessary and the flight continued uneventfully. Callback conversation with reporter revealed the following information: the reporter stated the aircraft was a B727-200 and the component or components that failed is unknown.
Original NASA ASRS Text
Title: A B727-200 IN CRUISE AT FL230 MADE AN EMER DSCNT DUE TO LOSS OF CABIN PRESSURE DUE TO THE L AIR CONDITIONING PACK FAILURE.
Narrative: AS WE WERE LEVELING AT FL230, HEARD SHORT BEEP IN COCKPIT. AS WE INVESTIGATED ITS CAUSE, THE ALT WARNING HORN BEGAN TO SOUND STEADILY. CABIN ALT WAS ABOUT 10500 FT AND RISING AT A RATE OF ABOUT 500 FPM. THE SO OBSERVED THE OUTFLOW VALVE WAS CLOSED AND RECYCLED THE PACKS. AT THAT TIME WE OBTAINED CLRNC TO DSND OUT OF FL230. WE COMMENCED DSCNT AND THE SO REGAINED CTL OF THE CABIN AS WE BEGAN OUR DSCNT. THE MASKS IN THE CABIN DID NOT DEPLOY AND WE CONTINUED DSCNT, WITH ATC CLRNC TO 10000 FT. WE WERE ABLE TO DETERMINE THAT THE R PACK WOULD HOLD CABIN PRESSURE, BUT THE L PACK WOULD NOT. THE APPROPRIATE CHKLISTS AND PROCS WERE PERFORMED AS NECESSARY AND THE FLT CONTINUED UNEVENTFULLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE ACFT WAS A B727-200 AND THE COMPONENT OR COMPONENTS THAT FAILED IS UNKNOWN.
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.