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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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A large transport returned to the field due to unable to pressurize the cabin on 1 pack during climb out.
| Attributes | |
| ACN | 362724 |
| Time | |
| Date | 199703 |
| Day | Thu |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : slc |
| State Reference | UT |
| Altitude | msl bound lower : 16000 msl bound upper : 16000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tower : sux |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude other |
| Route In Use | enroute airway : zlc |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : instrument pilot : atp pilot : cfi pilot : commercial |
| Experience | flight time last 90 days : 160 flight time total : 3800 flight time type : 160 |
| ASRS Report | 362724 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : far non adherence : published procedure other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
During our preflight inspection we found the right mix valve inoperative in both automatic and manual temperature control. After an on- site maintenance review and coordination with company maintenance, per our MEL, the right mix valve was placarded inoperative, rendering the right pack inoperative. We were then dispatched for a single pack takeoff and flight. After takeoff we were unable to maintain adequate cabin pressure with only the left pack. The cabin continued to climb at 800 FPM as we climbed on the departure route. Recognizing the problem we stopped climb and maintained 16000 ft then descended to 14000 ft in holding while trying to resolve the problem. After consulting our company we returned to slc, landing over maximum certificated landing weight. After returning to the gate, maintenance inspected the aircraft and found no discrepancies with the pressurization system. The placard on the right mix valve was reworded as mix valve inoperative in the mid position, right pack usable. We were then dispatched for a 2 pack takeoff from slc to stl.
Original NASA ASRS Text
Title: A LGT RETURNED TO THE FIELD DUE TO UNABLE TO PRESSURIZE THE CABIN ON 1 PACK DURING CLBOUT.
Narrative: DURING OUR PREFLT INSPECTION WE FOUND THE R MIX VALVE INOP IN BOTH AUTOMATIC AND MANUAL TEMP CTL. AFTER AN ON- SITE MAINT REVIEW AND COORD WITH COMPANY MAINT, PER OUR MEL, THE R MIX VALVE WAS PLACARDED INOP, RENDERING THE R PACK INOP. WE WERE THEN DISPATCHED FOR A SINGLE PACK TKOF AND FLT. AFTER TKOF WE WERE UNABLE TO MAINTAIN ADEQUATE CABIN PRESSURE WITH ONLY THE L PACK. THE CABIN CONTINUED TO CLB AT 800 FPM AS WE CLBED ON THE DEP RTE. RECOGNIZING THE PROB WE STOPPED CLB AND MAINTAINED 16000 FT THEN DSNDED TO 14000 FT IN HOLDING WHILE TRYING TO RESOLVE THE PROB. AFTER CONSULTING OUR COMPANY WE RETURNED TO SLC, LNDG OVER MAX CERTIFICATED LNDG WT. AFTER RETURNING TO THE GATE, MAINT INSPECTED THE ACFT AND FOUND NO DISCREPANCIES WITH THE PRESSURIZATION SYS. THE PLACARD ON THE R MIX VALVE WAS REWORDED AS MIX VALVE INOP IN THE MID POS, R PACK USABLE. WE WERE THEN DISPATCHED FOR A 2 PACK TKOF FROM SLC TO STL.
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.