A (BOMBARDIER) DEHAVILLAND DHC-8-200 ACFT MAINT TECHNICAL CALLOUT REQUIRED THE #2 ENG R HAND FORWARD; OUTBOARD ENG MOUNT TO BE REPLACED. FORWARD LEFT MOUNT SPACER NOT REINSTALLED WHEN ALL THREE ENG MOUNTS REASSEMBLED.

Narrative

MAINT PROC WAS TO REPLACE #2 ENG OUTBOARD FORWARD SIDE MOUNT AFT ISOLATOR WHICH REQUIRED INBOARD FORWARD SIDE MOUNT AND TOP FORWARD MOUNT TO BE LOOSENED. INSTEAD; IT WAS DISASSEMBLED AS WELL AND I DID NOT FOCUS ON THE INBOARD MOUNT AS MUCH AS I FOCUSED ON THE OUTBOARD MOUNT. CONSEQUENTLY; I MISSED THE ASSEMBLY OF INBOARD MOUNT AND DID NOT DETECT THE SPACER NOT INSTALLED INTERNALLY BTWN ISOLATORS. MISCOM BTWN MECHS AND ME; THE INSPECTOR. MORE FOCUS ON MY PART; NOT ALLOWING MYSELF TO BE CAUGHT UP IN THE RUSH TO GET AIRPLANES OUT AND SLOWING DOWN. SUPPLEMENTAL INFO FROM ACN 774075: THE R-HAND FORWARD SIDE MOUNT WAS REMOVED AND REPLACED TO ACCOMPLISH THE ABOVE TECHNICAL CALLOUT. IN ORDER TO REPLACE THE R-HAND FORWARD SIDE MOUNT; THE L-HAND FORWARD SIDE MOUNT AND THE TOP FORWARD MOUNT WERE REQUIRED TO BE REMOVED. ALL 3 FORWARD MOUNTS WERE REMOVED. A NEW MOUNT WAS INSTALLED IN THE R-HAND FORWARD SIDE MOUNT LOCATION; AND THE FORWARD TOP AND L-HAND FORWARD SIDE MOUNTS WERE REINSTALLED. UPON REASSEMBLY OF THE L-HAND FORWARD SIDE MOUNT; THE SPACER THAT FITS INSIDE THE PADS WAS (INADVERTENTLY) NOT REINSTALLED. ABOUT 1 WK LATER; THE ACFT CAME IN AGAIN FOR MAINT FOR AN 'A' CHK. A MECH OPENED THE SIDE COWL DOORS ON THE #2 ENG AND FOUND THE SPACER LYING IN THE LOWER COWL. MAINT INVESTIGATED; AND CORRECTLY ASCERTAINED THAT THE SPACER WAS MISSING FROM THE L-HAND FORWARD SIDE MOUNT; DUE TO THE APPEARANCE AND CONDITION OF THE MOUNT. MAINT WROTE A NON ROUTINE CARD TO REPLACE THE MOUNT. THE MOUNT WAS REPLACED. THE OTHER MOUNTS WERE INSPECTED FOR DEFECTS AND NO OTHER DEFECTS WERE NOTED. SUPPLEMENTAL INFO FROM ACN 774755: I WAS WORKING WITH MR X TO REPLACE AFT PORTION OF FORWARD OUTBOARD MOUNT ON #2 ENG. TO REPLACE THE AFT PORTION; IT IS REQUIRED TO REMOVE BOTH FORWARD MOUNTS AND THE TOP MOUNT. ONCE THE OUTBOARD PORTION WAS REPLACED; I REASSEMBLED THE OUTBOARD MOUNT AND INSTALLED MOUNTING HARDWARE. MR X DID THE SAME FOR THE INBOARD MOUNT. WE THEN TORQUED THE MOUNTS; I HELD THE BOLT HEADS WHILE MR X TORQUED THE NUTS. I INSTALLED THE COTTER PINS. MR Y WAS THE INSPECTOR. I DID NOT VERIFY THAT MR X KNEW THE CORRECT STACK-UP OF THE ENG MOUNT; HE HAD NOT ASKED HOW IT WENT; SO I THOUGHT HE KNEW. I HAD BEEN UP APPROX 20 HRS; IT WAS MY FIRST NIGHT BACK ON AFTER 2 WKS OF BEING OFF; VACATION AND TRAINING. SUPPLEMENTAL INFO FROM ACN 778032: AN ENG MOUNT SPACER WAS LEFT UNINSTALLED AND WITHIN THE COWLING OF ACFT X. THERE WERE 3 PEOPLE DIRECTLY INVOLVED WITH THE TASK. THE EVENT TOOK PLACE AT THE ZZZ MAINT HANGAR. I WAS ASSIGNED BY MY LEAD TO ASSIST MR Z WITH THE ENG MOUNTS ON ACFT X. I REMEMBER THE TASK WAS VERY STRESSFUL BECAUSE OF THE DIFFICULTY IN GETTING THE MOUNTS INSTALLED. I WAS PHYSICALLY AND MENTALLY GETTING EXHAUSTED DUE TO THE FACT THAT IN ORDER TO HELP MR Z TO GET HIS MOUNT INSTALLED; I HAD TO REPEATEDLY MOVE THE ENG BACK AND FORTH FROM A VERY UNCOMFORTABLE POS FOR AN EXTENDED PERIOD OF TIME. I DON'T RECALL WHO TOOK OUT THE ORIGINAL MOUNTS AND INSTALLED THE NEW ONES ONTO THE ACFT AND/OR WHO TORQUED THE HARDWARE. MY ONLY MEMORY I CAN GIVE IS THAT I DO REMEMBER HOW DIFFICULT OF A TIME IT WAS TO GET THE NEW MOUNTS INSTALLED.