|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : zzz.airport|
|Altitude||msl single value : 2000|
|Controlling Facilities||tracon : zzz.tracon|
|Operator||common carrier : air carrier|
|Make Model Name||B737-500|
|Operating Under FAR Part||Part 121|
|Flight Phase||climbout : intermediate altitude|
|Route In Use||departure sid : n/s|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Experience||flight time last 90 days : 240|
flight time total : 12500
flight time type : 3500
|Anomaly||aircraft equipment problem : less severe|
|Independent Detector||other flight crewa|
|Resolutory Action||flight crew : overcame equipment problem|
Maintenance Human Performance
Aircraft had recent maintenance history of bleed problems from #1 engine bleed. ZZZ maintenance had done extensive repair and testing prior to our flight. At 1000 ft on climb out; noticed a hot air pack or smoke odor. First officer did as well. At 3000 ft; during after-takeoff check; noticed left pneumatic pressure fluctuating between 20-40 psi. Almost immediately thereafter; the 'bleed trip' light illuminated. First officer was flying; and took over the radios as well. Performed irregular procedure in afm and the bleed reset and tripped again within 2 mins. Contacted dispatch and maintenance by radio (this point we were through FL180) and discussed the failures; history and current condition. After coordination and discussion; it was agreed that we would continue to ZZZ1 at FL250 using the 1 pack operation checklist. We also note that with the engine 1 bleed valve closed; there was no further hot pack or smoke odor. We continued to ZZZ1 at FL250 uneventfully until descent. Upon start of descent on 1 bleed/pack; the cabin altitude started to rise rapidly once the throttles were at idle. Based on the pneumatic pressure indication; I believe that the engine 2 bleed failed to open the high stage bleed valve. We added sufficient power to get enough air to bring the cabin down for landing. Going through 17000 ft; we started the APU and used the APU bleed on pack #1 to assist in getting the cabin down for landing without having to add power all the time. Landed safely and uneventfully.
Original NASA ASRS Text
Title: A B737-500 NOTED HOT PACK ODOR SHORTLY AFTER TAKEOFF. THEY THEN EXPERIENCED A BLEED TRIP AND; AFTER FOLLOWING FLT MAN PROCEDURES; CONTINUED TO DEST ON ONE PACK.
Narrative: ACFT HAD RECENT MAINT HISTORY OF BLEED PROBS FROM #1 ENG BLEED. ZZZ MAINT HAD DONE EXTENSIVE REPAIR AND TESTING PRIOR TO OUR FLT. AT 1000 FT ON CLBOUT; NOTICED A HOT AIR PACK OR SMOKE ODOR. FO DID AS WELL. AT 3000 FT; DURING AFTER-TKOF CHK; NOTICED L PNEUMATIC PRESSURE FLUCTUATING BTWN 20-40 PSI. ALMOST IMMEDIATELY THEREAFTER; THE 'BLEED TRIP' LIGHT ILLUMINATED. FO WAS FLYING; AND TOOK OVER THE RADIOS AS WELL. PERFORMED IRREGULAR PROC IN AFM AND THE BLEED RESET AND TRIPPED AGAIN WITHIN 2 MINS. CONTACTED DISPATCH AND MAINT BY RADIO (THIS POINT WE WERE THROUGH FL180) AND DISCUSSED THE FAILURES; HISTORY AND CURRENT CONDITION. AFTER COORD AND DISCUSSION; IT WAS AGREED THAT WE WOULD CONTINUE TO ZZZ1 AT FL250 USING THE 1 PACK OP CHKLIST. WE ALSO NOTE THAT WITH THE ENG 1 BLEED VALVE CLOSED; THERE WAS NO FURTHER HOT PACK OR SMOKE ODOR. WE CONTINUED TO ZZZ1 AT FL250 UNEVENTFULLY UNTIL DSCNT. UPON START OF DSCNT ON 1 BLEED/PACK; THE CABIN ALT STARTED TO RISE RAPIDLY ONCE THE THROTTLES WERE AT IDLE. BASED ON THE PNEUMATIC PRESSURE INDICATION; I BELIEVE THAT THE ENG 2 BLEED FAILED TO OPEN THE HIGH STAGE BLEED VALVE. WE ADDED SUFFICIENT PWR TO GET ENOUGH AIR TO BRING THE CABIN DOWN FOR LNDG. GOING THROUGH 17000 FT; WE STARTED THE APU AND USED THE APU BLEED ON PACK #1 TO ASSIST IN GETTING THE CABIN DOWN FOR LNDG WITHOUT HAVING TO ADD PWR ALL THE TIME. LANDED SAFELY AND UNEVENTFULLY.
Data retrieved from NASA's ASRS site as of May 2009 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.