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Air carrier large transport unable to control cabin pressure during rapid climb has to descend to regain control. Flight crew used O2 masks but passenger O2 not activated or needed as cabin altitude never got above 10000'.
| Attributes | |
| ACN | 149353 |
| Time | |
| Date | 199006 |
| Day | Sun |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : iah |
| State Reference | TX |
| Altitude | msl bound lower : 10000 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zhu |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Flight Phase | climbout : intermediate altitude descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 10000 flight time type : 3500 |
| ASRS Report | 149353 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : second officer |
| Qualification | pilot : flight engineer pilot : atp |
| Experience | flight time last 90 days : 100 flight time total : 4500 flight time type : 270 |
| ASRS Report | 148638 |
| Events | |
| Anomaly | aircraft equipment problem : critical |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : overcame equipment problem flight crew : declared emergency |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
Narrative:
While climbing through FL250 to FL270 (with pilot discretion to FL240) cabin started climbing. Began descent to FL240 and requested and received clearance to 10000'. Could not control cabin with abnormal procedures. Cabin went to 10000'. Horn sounded and cabin began to descend immediately below 10000' as we were leveling off at 10000'. No emergency was declared nor was priority treatment requested. Masks were not needed and did not drop. Post-flight inspection revealed that some insulation had come loose and was keeping outflow valve from closing. Supplemental information from acn 148138: while we were descending and working the problem a F/a came to the cockpit and saw that we were wearing our O2 masks and she became overly concerned and went to the back and got an O2. The captain made a passenger announcement about the problem and that everything was ok.
Original NASA ASRS Text
Title: ACR LGT UNABLE TO CTL CABIN PRESSURE DURING RAPID CLIMB HAS TO DESCEND TO REGAIN CTL. FLT CREW USED O2 MASKS BUT PASSENGER O2 NOT ACTIVATED OR NEEDED AS CABIN ALT NEVER GOT ABOVE 10000'.
Narrative: WHILE CLBING THROUGH FL250 TO FL270 (WITH PLT DISCRETION TO FL240) CABIN STARTED CLBING. BEGAN DSNT TO FL240 AND REQUESTED AND RECEIVED CLRNC TO 10000'. COULD NOT CTL CABIN WITH ABNORMAL PROCS. CABIN WENT TO 10000'. HORN SOUNDED AND CABIN BEGAN TO DSND IMMEDIATELY BELOW 10000' AS WE WERE LEVELING OFF AT 10000'. NO EMER WAS DECLARED NOR WAS PRIORITY TREATMENT REQUESTED. MASKS WERE NOT NEEDED AND DID NOT DROP. POST-FLT INSPECTION REVEALED THAT SOME INSULATION HAD COME LOOSE AND WAS KEEPING OUTFLOW VALVE FROM CLOSING. SUPPLEMENTAL INFO FROM ACN 148138: WHILE WE WERE DSNDING AND WORKING THE PROB A F/A CAME TO THE COCKPIT AND SAW THAT WE WERE WEARING OUR O2 MASKS AND SHE BECAME OVERLY CONCERNED AND WENT TO THE BACK AND GOT AN O2. THE CAPT MADE A PAX ANNOUNCEMENT ABOUT THE PROB AND THAT EVERYTHING WAS OK.
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.