 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Large transport aircraft on one air conditioning pack at FL250. Pack failed. Loss of pressurization. Emergency descent.
| Attributes | |
| ACN | 119617 |
| Time | |
| Date | 198908 |
| Day | Sun |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : omn |
| State Reference | FL |
| Altitude | msl bound lower : 14000 msl bound upper : 25000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 3 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other cruise other descent other |
| Route In Use | enroute : other oceanic enroute : atlantic enroute airway : ar7 |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : cfi pilot : atp pilot : flight engineer pilot : instrument |
| Experience | flight time last 90 days : 200 flight time total : 6000 flight time type : 800 |
| ASRS Report | 119617 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : critical other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : exited adverse environment flight crew : overcame equipment problem |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Flight dispatched with left air conditioning pack inoperative. Upon reaching cruise altitude (FL250) approximately 40 mins after departure from mia, the right air conditioning pack tripped off due to overwork (over temperature) from one pack working to cool full aircraft. After departure from 90 degree F temperatures at mia, pack temperature (hi) at this time (pack temperature 90 C) and supply duct temperature (55 F), initial attempt at pack reset failed. Initiated a 'rapid descent' by captain (my leg). I then assumed first officer duties (oxy mask, passenger brief, notify ATC of situation, etc). During rapid descent with ATC clearance, pack was successfully reset thru FL180. Cabin altitude did not exceed 6500' and no masks were dropped. From this position at 14,000', proceeded directly to coast (direct ormond beach, fl direct sav etc to rdu). With ATC clearance and flight continuation on to raleigh durham (rdu) at 13,000', eventually (correct altitude for direction). All subsequent pressurization and right pack operations were normal, except cabin temperature never cooled below 78 degree F. Aircraft given to maintenance at rdu. Remainder of flight normal. I flew aircraft after the rapid descent, level off at 14,000', while captain and F/east performed checklists, etc. I completed the leg. Remainder of leg (flight) normal.
Original NASA ASRS Text
Title: LGT ACFT ON ONE AIR CONDITIONING PACK AT FL250. PACK FAILED. LOSS OF PRESSURIZATION. EMERGENCY DESCENT.
Narrative: FLT DISPATCHED WITH LEFT AIR CONDITIONING PACK INOP. UPON REACHING CRUISE ALT (FL250) APPROX 40 MINS AFTER DEP FROM MIA, THE RIGHT AIR CONDITIONING PACK TRIPPED OFF DUE TO OVERWORK (OVER TEMPERATURE) FROM ONE PACK WORKING TO COOL FULL ACFT. AFTER DEP FROM 90 DEG F TEMPS AT MIA, PACK TEMPERATURE (HI) AT THIS TIME (PACK TEMPERATURE 90 C) AND SUPPLY DUCT TEMPERATURE (55 F), INITIAL ATTEMPT AT PACK RESET FAILED. INITIATED A 'RAPID DESCENT' BY CAPT (MY LEG). I THEN ASSUMED F/O DUTIES (OXY MASK, PAX BRIEF, NOTIFY ATC OF SITUATION, ETC). DURING RAPID DESCENT WITH ATC CLRNC, PACK WAS SUCCESSFULLY RESET THRU FL180. CABIN ALT DID NOT EXCEED 6500' AND NO MASKS WERE DROPPED. FROM THIS POSITION AT 14,000', PROCEEDED DIRECTLY TO COAST (DIRECT ORMOND BEACH, FL DIRECT SAV ETC TO RDU). WITH ATC CLRNC AND FLT CONTINUATION ON TO RALEIGH DURHAM (RDU) AT 13,000', EVENTUALLY (CORRECT ALT FOR DIRECTION). ALL SUBSEQUENT PRESSURIZATION AND RIGHT PACK OPS WERE NORMAL, EXCEPT CABIN TEMPERATURE NEVER COOLED BELOW 78 DEG F. ACFT GIVEN TO MAINT AT RDU. REMAINDER OF FLT NORMAL. I FLEW ACFT AFTER THE RAPID DESCENT, LEVEL OFF AT 14,000', WHILE CAPT AND F/E PERFORMED CHECKLISTS, ETC. I COMPLETED THE LEG. REMAINDER OF LEG (FLT) NORMAL.
Data retrieved from NASA's ASRS site as of August 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.