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B737 flight crew departs slc with a pack on MEL after rumbling noise is heard during taxi and ice in pack is suspected as the cause. Cabin altitude begins to rise with single pack operation at FL250 and crew elects to use the deferred pack rather than descend. This works and flight continues to destination.
| Attributes | |
| ACN | 830711 |
| Time | |
| Date | 200904 |
| Local Time Of Day | 1201-1800 |
| Place | |
| Locale Reference | SLC.Airport |
| State Reference | UT |
| Aircraft 1 | |
| Make Model Name | B737-500 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Cruise |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Air Conditioning and Pressurization Pack |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Experience | Flight Crew Last 90 Days 150 Flight Crew Total 15000 Flight Crew Type 10000 |
| Person 2 | |
| Function | Captain Pilot Not Flying |
| Experience | Flight Crew Last 90 Days 110 Flight Crew Total 19000 Flight Crew Type 15000 |
| Events | |
| Anomaly | Aircraft Equipment Problem Less Severe Deviation - Procedural FAR Deviation - Procedural Maintenance Deviation - Procedural Published Material / Policy |
Narrative:
As we taxied to the runway in slc; the flight attendants called to inform us of a loud noise coming from mid-cabin. We pulled over at the end of the runway and I; the first officer; went back to the cabin to investigate. After some troubleshooting; we discovered that the right pack was the cause of the noise; and the noise would stop when that pack was shut off. We contacted our maintenance controller who felt that the cause was ice in the air cycle machine. They deferred the pack and we were refiled for FL250; single pack. Everything was normal; pressurization wise; as we climbed and leveled off. Soon after leveling off at FL250; I noticed that the cabin altitude was still climbing at 500 FPM and was nearing 8;000 ft cabin altitude. We verified that the outflow valve was closed and decided that our only recourse was either to descend over very high terrain or to turn the deferred pack back on. The flight attendant stated that the noise was gone. The cabin altitude was restored and we decided to continue at FL250 rather than divert when all indications were normal.
Original NASA ASRS Text
Title: B737 flight crew departs SLC with a PACK on MEL after rumbling noise is heard during taxi and ice in PACK is suspected as the cause. Cabin altitude begins to rise with single PACK operation at FL250 and crew elects to use the deferred PACK rather than descend. This works and flight continues to destination.
Narrative: As we taxied to the runway in SLC; the Flight Attendants called to inform us of a loud noise coming from mid-cabin. We pulled over at the end of the runway and I; the First Officer; went back to the cabin to investigate. After some troubleshooting; we discovered that the right pack was the cause of the noise; and the noise would stop when that pack was shut off. We contacted our Maintenance Controller who felt that the cause was ice in the air cycle machine. They deferred the pack and we were refiled for FL250; single pack. Everything was normal; pressurization wise; as we climbed and leveled off. Soon after leveling off at FL250; I noticed that the cabin altitude was still climbing at 500 FPM and was nearing 8;000 FT cabin altitude. We verified that the outflow valve was closed and decided that our only recourse was either to descend over very high terrain or to turn the deferred pack back on. The Flight Attendant stated that the noise was gone. The cabin altitude was restored and we decided to continue at FL250 rather than divert when all indications were normal.
Data retrieved from NASA's ASRS site as of April 2012 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.