Narrative:

This is in regards to part number wxxz radial drive shaft on the rb-211 (B757 aircraft). For some time we have been having steady bearing (wxxz) failures in the field which dealt with a particular lot number of bearings. Since then they have discovered that this problem is not restr to the lot number, but all of the old part numbers. While air carrier is trying very hard to get these parts off wing, company X cannot supply the amount of new bearings wxxz to air carrier. My concern is we know that we have a minimum of 30 shaft drives on wing that are subject to this high failure rate, and I emphasize minimum 30 shafts. The problem is, per our meeting on oct/tue/00, the only thing we are doing is checking the oil filter every 85 hours. Unfortunately, once contamination shows up in the filter it's too late and the bearing has already failed. I have suggested that the shafts are removed on overnight checks and the bearings are inspected. The concern our engineering department has is we might find a bad one and possibly have an aircraft on ground. So, they would rather fly an aircraft with a bad bearing and possibly an in-flight shutdown than park an aircraft. I must stress that when this bearing fails the engine immediately shuts down, and we recently had this very thing happen with an emergency landing in XXX. Also, we have an aircraft that a shaft was removed from the #2 engine. This bearing has contaminated this engine with 4 steel rivets and an unknown amount of metal from the deteriorating bearing cage. I was told by air carrier engineering that they are not concerned with contamination in the engine. Furthermore, the other engine on the same is flying with a known bad bearing. My point being that this aircraft is in service with two high suspect failure engines.

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Original NASA ASRS Text

Title: A LEAD TECHNICIAN RPTS RB-211 ENGS ON B757-200 ACR ACFT HAVING RADIAL SHAFT BEARING FAILURE AND SOME OPERATING WITH KNOWN SUSPECT BEARINGS.

Narrative: THIS IS IN REGARDS TO PART NUMBER WXXZ RADIAL DRIVE SHAFT ON THE RB-211 (B757 ACFT). FOR SOME TIME WE HAVE BEEN HAVING STEADY BEARING (WXXZ) FAILURES IN THE FIELD WHICH DEALT WITH A PARTICULAR LOT NUMBER OF BEARINGS. SINCE THEN THEY HAVE DISCOVERED THAT THIS PROB IS NOT RESTR TO THE LOT NUMBER, BUT ALL OF THE OLD PART NUMBERS. WHILE ACR IS TRYING VERY HARD TO GET THESE PARTS OFF WING, COMPANY X CANNOT SUPPLY THE AMOUNT OF NEW BEARINGS WXXZ TO ACR. MY CONCERN IS WE KNOW THAT WE HAVE A MINIMUM OF 30 SHAFT DRIVES ON WING THAT ARE SUBJECT TO THIS HIGH FAILURE RATE, AND I EMPHASIZE MINIMUM 30 SHAFTS. THE PROB IS, PER OUR MEETING ON OCT/TUE/00, THE ONLY THING WE ARE DOING IS CHKING THE OIL FILTER EVERY 85 HRS. UNFORTUNATELY, ONCE CONTAMINATION SHOWS UP IN THE FILTER IT'S TOO LATE AND THE BEARING HAS ALREADY FAILED. I HAVE SUGGESTED THAT THE SHAFTS ARE REMOVED ON OVERNIGHT CHKS AND THE BEARINGS ARE INSPECTED. THE CONCERN OUR ENGINEERING DEPT HAS IS WE MIGHT FIND A BAD ONE AND POSSIBLY HAVE AN ACFT ON GND. SO, THEY WOULD RATHER FLY AN ACFT WITH A BAD BEARING AND POSSIBLY AN INFLT SHUTDOWN THAN PARK AN ACFT. I MUST STRESS THAT WHEN THIS BEARING FAILS THE ENG IMMEDIATELY SHUTS DOWN, AND WE RECENTLY HAD THIS VERY THING HAPPEN WITH AN EMER LNDG IN XXX. ALSO, WE HAVE AN ACFT THAT A SHAFT WAS REMOVED FROM THE #2 ENG. THIS BEARING HAS CONTAMINATED THIS ENG WITH 4 STEEL RIVETS AND AN UNKNOWN AMOUNT OF METAL FROM THE DETERIORATING BEARING CAGE. I WAS TOLD BY ACR ENGINEERING THAT THEY ARE NOT CONCERNED WITH CONTAMINATION IN THE ENG. FURTHERMORE, THE OTHER ENG ON THE SAME IS FLYING WITH A KNOWN BAD BEARING. MY POINT BEING THAT THIS ACFT IS IN SVC WITH TWO HIGH SUSPECT FAILURE ENGS.

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.