Narrative:

I was notified that aircraft X experienced a 'rollback' on #1 engine. I signed for and accomplished engineering order xyz as referenced by the card and with all supplied parts. Callback conversation with reporter revealed the following information: reporter stated he had previously completed an engineering change order to check the PT2 sense line in the nose cowl for wear and install a new type of rubber cushioned clamp. The older style of metal clamp inner rubber cushion did not completely wrap around the PT2 line when attached to the nose cowl inner structure. This allowed a section of the tube to wear against the metal portion of the clamp. Reporter stated this maintenance work was driven by an a.D. Requiring the metal clamp changes on all rb-211 engines on the B757 aircraft; including the #1 engine he had worked. He was told one of the PT2 sense line had broken causing the #1 engine throttle to roll back to idle; during climbout. Reporter stated he had earlier identified some paperwork confusion in the engineering directive. Some of the PT2 sense lines have configurations that include anti-ice wiring that are also attached to the PT2 line. These required four clamps (clips) to be changed; instead of only one clamp. Reporter added that since the rollback incident of the #1 engine throttle to idle; his carrier decided to completely remove the section of the PT2 line to inspect for wear. As a result; inspectors and mechanics have found more areas of wear on the PT2 lines than expected.

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Original NASA ASRS Text

Title: MECHANIC IS INFORMED THE B757-200 ACFT HE HAD PREVIOUSLY WORKED; EXPERIENCED A #1 ENG THROTTLE ROLLBACK TO IDLE DURING CLIMBOUT.

Narrative: I WAS NOTIFIED THAT ACFT X EXPERIENCED A 'ROLLBACK' ON #1 ENG. I SIGNED FOR AND ACCOMPLISHED ENGINEERING ORDER XYZ AS REFED BY THE CARD AND WITH ALL SUPPLIED PARTS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED HE HAD PREVIOUSLY COMPLETED AN ENGINEERING CHANGE ORDER TO CHECK THE PT2 SENSE LINE IN THE NOSE COWL FOR WEAR AND INSTALL A NEW TYPE OF RUBBER CUSHIONED CLAMP. THE OLDER STYLE OF METAL CLAMP INNER RUBBER CUSHION DID NOT COMPLETELY WRAP AROUND THE PT2 LINE WHEN ATTACHED TO THE NOSE COWL INNER STRUCTURE. THIS ALLOWED A SECTION OF THE TUBE TO WEAR AGAINST THE METAL PORTION OF THE CLAMP. REPORTER STATED THIS MAINT WORK WAS DRIVEN BY AN A.D. REQUIRING THE METAL CLAMP CHANGES ON ALL RB-211 ENGINES ON THE B757 ACFT; INCLUDING THE #1 ENG HE HAD WORKED. HE WAS TOLD ONE OF THE PT2 SENSE LINE HAD BROKEN CAUSING THE #1 ENG THROTTLE TO ROLL BACK TO IDLE; DURING CLIMBOUT. REPORTER STATED HE HAD EARLIER IDENTIFIED SOME PAPERWORK CONFUSION IN THE ENGINEERING DIRECTIVE. SOME OF THE PT2 SENSE LINES HAVE CONFIGURATIONS THAT INCLUDE ANTI-ICE WIRING THAT ARE ALSO ATTACHED TO THE PT2 LINE. THESE REQUIRED FOUR CLAMPS (CLIPS) TO BE CHANGED; INSTEAD OF ONLY ONE CLAMP. REPORTER ADDED THAT SINCE THE ROLLBACK INCIDENT OF THE #1 ENGINE THROTTLE TO IDLE; HIS CARRIER DECIDED TO COMPLETELY REMOVE THE SECTION OF THE PT2 LINE TO INSPECT FOR WEAR. AS A RESULT; INSPECTORS AND MECHANICS HAVE FOUND MORE AREAS OF WEAR ON THE PT2 LINES THAN EXPECTED.

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.