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An air carrier flight crew flying a B737-200 from anc experiences an excessive cabin leak rate through the cargo door seals at FL250 resulting in an immediate descent to a lower altitude.
| Attributes | |
| ACN | 459142 |
| Time | |
| Date | 199912 |
| Day | Wed |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | navaid : anc.vor |
| State Reference | AK |
| Altitude | msl single value : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zan.artcc tower : mke.tower |
| Operator | common carrier : air carrier |
| Make Model Name | B737-200 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : multi engine pilot : atp |
| Experience | flight time last 90 days : 240 flight time total : 17000 flight time type : 8500 |
| ASRS Report | 459142 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : multi engine pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 13000 flight time type : 3000 |
| ASRS Report | 458202 |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude other anomaly other |
| Independent Detector | other controllera other flight crewa other flight crewb |
| Resolutory Action | aircraft : equipment problem dissipated controller : issued new clearance controller : provided flight assist flight crew : overcame equipment problem |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Dispatched with r-hand air conditioning pack inoperative on MEL. After approximately 20 mins at FL250 (cruise altitude with pack inoperative) the altitude warning horn came on. Checked cabin altitude at 10000 ft and climbing. Donned oxygen mask and immediately tried to contact zan for lower altitude. After 2 attempts to contact ATC for lower (they were busy on at least 2 different frequencys) we started a descent in VMC. Finally got through to ATC and got lower altitude. When approximately 700 ft below assigned altitude, the use of the word 'emergency' in my initial contact with ATC may have allowed us to get a descent sooner.
Original NASA ASRS Text
Title: AN ACR FLC FLYING A B737-200 FROM ANC EXPERIENCES AN EXCESSIVE CABIN LEAK RATE THROUGH THE CARGO DOOR SEALS AT FL250 RESULTING IN AN IMMEDIATE DSCNT TO A LOWER ALT.
Narrative: DISPATCHED WITH R-HAND AIR CONDITIONING PACK INOP ON MEL. AFTER APPROX 20 MINS AT FL250 (CRUISE ALT WITH PACK INOP) THE ALT WARNING HORN CAME ON. CHKED CABIN ALT AT 10000 FT AND CLBING. DONNED OXYGEN MASK AND IMMEDIATELY TRIED TO CONTACT ZAN FOR LOWER ALT. AFTER 2 ATTEMPTS TO CONTACT ATC FOR LOWER (THEY WERE BUSY ON AT LEAST 2 DIFFERENT FREQS) WE STARTED A DSCNT IN VMC. FINALLY GOT THROUGH TO ATC AND GOT LOWER ALT. WHEN APPROX 700 FT BELOW ASSIGNED ALT, THE USE OF THE WORD 'EMER' IN MY INITIAL CONTACT WITH ATC MAY HAVE ALLOWED US TO GET A DSCNT SOONER.
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.