WRONG PART INSTALLED IN LNDG GEAR CAUSED A RETURN LAND.

Narrative

I WAS ASSIGNED TO AN ACFT; FOR A MAINT OPPORTUNITY VISIT OF APPROX 5 1/2 HRS BEFORE ITS NEXT SCHEDULED DEP; WHICH WAS FLT X ON THE EVENING OF JUL/XX/94. MYSELF AND ANOTHER MECH WERE ASSIGNED THE TASK OF PERFORMING A CHANGE ORDER AUTH (COA) TO THE L WING LNDG GEAR WHICH INVOLVED REMOVING THE DOWNLOCK ACTUATOR AND REPLACING IT WITH AN IMPROVED ACTUATOR. OUR LEAD MECH GAVE US OUR NECESSARY COA PAPERWORK AND WE SET UP FOR THE TASK. I ORDERED THE PART (ACTUATOR). PER THE PAPERWORK; WE REMOVED AND REPLACED THE ACTUATOR AND PERFORMED THE OPERATIONAL CHK WHICH CHKED GOOD. THE ACTUATOR WAS A MAINT RECORD PART; SO THE MAINT RECORD NUMBERS WERE NEEDED FOR THE PAPERWORK TO SIGN OFF THE JOB. WHILE RECORDING THESE NUMBERS; I NOTICED THAT THEY WERE DIFFERENT; AS DID MY PARTNER; BUT DID NOTHING TO FURTHER INVESTIGATE THIS BECAUSE I THOUGHT SINCE THIS WAS A COA; THE PART NUMBERS WERE CHANGING ON PURPOSE. AS I WAS GOING BACK THROUGH THE PAPERWORK; I REALIZED THE PAPERWORK THAT HAD BEEN PRINTED WAS FOR A BODY LNDG GEAR. I TOOK THIS TO MY LEAD; AND HE RELAYED IT TO MGMNT; AS THEY WERE RESPONSIBLE FOR THIS PAPERWORK. (PRINTING IT) THE LEAD MECH THEN WENT BACK HIMSELF AND PRINTED THE CORRECT COA PAPERWORK. I THEN REVIEWED THE CORRECT COA PAPERWORK; WENT THROUGH THE REMOVAL AND INSTALLATION; AND OPS CHK PROCS WHICH WERE BASICALLY IDENTICAL. I THEN SIGNED OFF THE PAPERWORK FOR THE COA. ACFT N LEFT HONOLULU AT APPROX XG15 AND RETURNED AT APPROX XH30 WITH LNDG GEAR PROBS. UPON FURTHER INVESTIGATION; IT WAS FOUND THAT THE WRONG ACTUATOR HAD BEEN INSTALLED WHICH WAS NOT LETTING THE GEAR RETRACT FULLY. THIS WAS THE ACTUATOR WHICH WAS LISTED ON THE ORIGINAL INCORRECT PAPERWORK. BOTH OF THE NEW AND OLD ACTUATOR ARE IDENTICAL IN SIZE AND SHAPE. ALTHOUGH I SHOULD HAVE CAUGHT THE ERROR IN PAPERWORK; I FEEL THE PARTY IN MGMNT WAS JUST AS RESPONSIBLE BECAUSE THEY PRINTED IT UP; AND THAT'S WHAT GOT THE EVENT STARTED IN THE WRONG DIRECTION.