Narrative:

Crew departed ZZZZ, first officer, after completion of maintenance on the #1 pack system. While climbing through 14000 ft, the crew started smelling smoke and fumes followed by unusual rumbling noise and vibrations in the cockpit area. While the captain was at the controls, the first officer declared an in flight emergency requesting immediate descent and vectors back to ZZZZ for ILS approach. Crew reviewed all applicable emergency procedures, including request for crash fire rescue crew standing by for our uneventful approach and landing. No further problems. Recommend a review of applicable maintenance procedures. Supplemental information from acn 634581: this aircraft is a prior air carrier Y aircraft where all of the #2 packs have been removed and deferred! Taking into consideration the prior maintenance, uncertainty of smoke source and proximity of departure airport, the decision was made and agreed by all crew members that an immediate return to ZZZZ, at 711000 pounds without dumping was the most prudent. Callback conversation with reporter acn 635156 revealed the following information: reporter stated the smoke, fumes, rumbling and vibration was caused by the failure of the #3 air cycle machine. The reporter said when it failed, it threw parts downstream into the water separator, cooling fan and check valves. The reporter stated these units, and a pack temperature controller, were replaced and an overweight landing inspection was accomplished. The reporter said inbound to this station on the overnight layover, the #1 pack had problems and some temperature sensors were replaced. Callback conversation with reporter acn 634581 revealed the following information: the reporter stated the crew noted a metallic smell and taste coming from the vent above the glare shield. The reporter said this was followed by a loud bang and vibration. The reporter stated an emergency was declared and a descent started and both packs shut down. The reporter said an overweight landing was made. The reporter stated the #3 pack air cycle machine had failed and damaged downstream components.

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Original NASA ASRS Text

Title: A B747-100 CLBING THROUGH 14000 FT DECLARED AN EMER AND RETURNED TO DEP ARPT DUE TO SMOKE AND FUMES ACCOMPANIED WITH RUMBLING AND VIBRATIONS CAUSED BY FAILED #3 PACK AIR CYCLE MACHINE.

Narrative: CREW DEPARTED ZZZZ, FO, AFTER COMPLETION OF MAINT ON THE #1 PACK SYSTEM. WHILE CLBING THROUGH 14000 FT, THE CREW STARTED SMELLING SMOKE AND FUMES FOLLOWED BY UNUSUAL RUMBLING NOISE AND VIBRATIONS IN THE COCKPIT AREA. WHILE THE CAPT WAS AT THE CTLS, THE FO DECLARED AN IN FLT EMER REQUESTING IMMEDIATE DSCNT AND VECTORS BACK TO ZZZZ FOR ILS APCH. CREW REVIEWED ALL APPLICABLE EMER PROCS, INCLUDING REQUEST FOR CRASH FIRE RESCUE CREW STANDING BY FOR OUR UNEVENTFUL APCH AND LNDG. NO FURTHER PROBS. RECOMMEND A REVIEW OF APPLICABLE MAINT PROCS. SUPPLEMENTAL INFO FROM ACN 634581: THIS ACFT IS A PRIOR ACR Y ACFT WHERE ALL OF THE #2 PACKS HAVE BEEN REMOVED AND DEFERRED! TAKING INTO CONSIDERATION THE PRIOR MAINT, UNCERTAINTY OF SMOKE SOURCE AND PROXIMITY OF DEP ARPT, THE DECISION WAS MADE AND AGREED BY ALL CREW MEMBERS THAT AN IMMEDIATE RETURN TO ZZZZ, AT 711000 LBS WITHOUT DUMPING WAS THE MOST PRUDENT. CALLBACK CONVERSATION WITH RPTR ACN 635156 REVEALED THE FOLLOWING INFO: RPTR STATED THE SMOKE, FUMES, RUMBLING AND VIBRATION WAS CAUSED BY THE FAILURE OF THE #3 AIR CYCLE MACHINE. THE RPTR SAID WHEN IT FAILED, IT THREW PARTS DOWNSTREAM INTO THE WATER SEPARATOR, COOLING FAN AND CHECK VALVES. THE RPTR STATED THESE UNITS, AND A PACK TEMP CTLR, WERE REPLACED AND AN OVERWEIGHT LNDG INSPECTION WAS ACCOMPLISHED. THE RPTR SAID INBOUND TO THIS STATION ON THE OVERNIGHT LAYOVER, THE #1 PACK HAD PROBS AND SOME TEMP SENSORS WERE REPLACED. CALLBACK CONVERSATION WITH RPTR ACN 634581 REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CREW NOTED A METALLIC SMELL AND TASTE COMING FROM THE VENT ABOVE THE GLARE SHIELD. THE RPTR SAID THIS WAS FOLLOWED BY A LOUD BANG AND VIBRATION. THE RPTR STATED AN EMER WAS DECLARED AND A DSCNT STARTED AND BOTH PACKS SHUT DOWN. THE RPTR SAID AN OVERWEIGHT LNDG WAS MADE. THE RPTR STATED THE #3 PACK AIR CYCLE MACHINE HAD FAILED AND DAMAGED DOWNSTREAM COMPONENTS.

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.