Narrative:

On wed, I participated in replacing #2 engine on aircraft X. Eighteen days later on a flight to salt lake city, the crew reported that #2 engine would not reduce power from the cruise power setting. The mechanic that worked the aircraft in salt lake city stated that the nut holding the throttle arm on the cross shaft had backed off. The nut on the left side of the cross shaft for throttle crank arm had not been safetied. The mechanic who rigged the throttle during the engine change had noticed the spacer for fuel cutoff crank arm installed incorrectly which he corrected, but did not disturb the throttle arm nut. Prior to being installed on the aircraft, the engine had a 'C' check performed and the gearbox replaced, during which the crank arms were installed on the cross shaft. Supplemental information from acn 318254: during the rig of the engine, it was discovered that the start lever crank was improperly installed and would not allow full throttle travel. The corrective action was to repos the start lever crank. At no time was any attention given to the throttle crank. No paperwork was generated for the start crank as it became a necessary part of the rig. All safeties that were disturbed were completed and inspected. Supplemental information from acn 318158: the engine gear box was replaced. The jam nut is part of the gear box installation. I was the inspector on the engine change and not the gear box. I probably should have looked at the safety on the gear box cross shaft, but I assumed that it was looked at as part of the gear box installation, and should have been.

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Original NASA ASRS Text

Title: A NUT ON A THROTTLE ARM WAS NOT SAFETIED. ON DSCNT CREW UNABLE TO REDUCE PWR LEVEL FROM CRUISE SETTING.

Narrative: ON WED, I PARTICIPATED IN REPLACING #2 ENG ON ACFT X. EIGHTEEN DAYS LATER ON A FLT TO SALT LAKE CITY, THE CREW RPTED THAT #2 ENG WOULD NOT REDUCE PWR FROM THE CRUISE PWR SETTING. THE MECH THAT WORKED THE ACFT IN SALT LAKE CITY STATED THAT THE NUT HOLDING THE THROTTLE ARM ON THE CROSS SHAFT HAD BACKED OFF. THE NUT ON THE L SIDE OF THE CROSS SHAFT FOR THROTTLE CRANK ARM HAD NOT BEEN SAFETIED. THE MECH WHO RIGGED THE THROTTLE DURING THE ENG CHANGE HAD NOTICED THE SPACER FOR FUEL CUTOFF CRANK ARM INSTALLED INCORRECTLY WHICH HE CORRECTED, BUT DID NOT DISTURB THE THROTTLE ARM NUT. PRIOR TO BEING INSTALLED ON THE ACFT, THE ENG HAD A 'C' CHK PERFORMED AND THE GEARBOX REPLACED, DURING WHICH THE CRANK ARMS WERE INSTALLED ON THE CROSS SHAFT. SUPPLEMENTAL INFO FROM ACN 318254: DURING THE RIG OF THE ENG, IT WAS DISCOVERED THAT THE START LEVER CRANK WAS IMPROPERLY INSTALLED AND WOULD NOT ALLOW FULL THROTTLE TRAVEL. THE CORRECTIVE ACTION WAS TO REPOS THE START LEVER CRANK. AT NO TIME WAS ANY ATTENTION GIVEN TO THE THROTTLE CRANK. NO PAPERWORK WAS GENERATED FOR THE START CRANK AS IT BECAME A NECESSARY PART OF THE RIG. ALL SAFETIES THAT WERE DISTURBED WERE COMPLETED AND INSPECTED. SUPPLEMENTAL INFO FROM ACN 318158: THE ENG GEAR BOX WAS REPLACED. THE JAM NUT IS PART OF THE GEAR BOX INSTALLATION. I WAS THE INSPECTOR ON THE ENG CHANGE AND NOT THE GEAR BOX. I PROBABLY SHOULD HAVE LOOKED AT THE SAFETY ON THE GEAR BOX CROSS SHAFT, BUT I ASSUMED THAT IT WAS LOOKED AT AS PART OF THE GEAR BOX INSTALLATION, AND SHOULD HAVE BEEN.

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.