|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0001 To 0600|
|Locale Reference||airport : zzz.airport|
|Altitude||agl single value : 0|
|Operator||common carrier : air carrier|
|Make Model Name||Q400 (Formerly Dash 8-400)|
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Affiliation||company : air carrier|
|Function||maintenance : technician|
|Anomaly||aircraft equipment problem : less severe|
maintenance problem : improper maintenance
non adherence : published procedure
non adherence : far
|Independent Detector||other other : 1|
|Resolutory Action||none taken : detected after the fact|
|Maintenance||contributing factor : briefing|
performance deficiency : training
performance deficiency : inspection
performance deficiency : scheduled maintenance
performance deficiency : non compliance with legal requirements
performance deficiency : installation
|Problem Areas||Maintenance Human Performance|
|Primary Problem||Maintenance Human Performance|
Nov/08; c-chk Q400; I was assigned to accomplish installation of the top engine mount of engine #1 and to continued tension spoilers after XA00 due to 24-hour soaking time. Swing shift took a turnover with who we had to proceed to install that top engine mount. Since I haven't done installation of engine mounts during my career time in air carrier; I asked my previous shift mechanic to brief me into it verbally; and later we used Q400 amm tasks for installation. Engine mounts were installed as per Q400 tasks; installation looked good and was inspected by our quality control inspector X. Yes; we did have some hard time during installation; due misalignment of one or the other engine mounts; but we got it aligned; installed; torqued and cotter-pinned as per Q400 amm tasks. All the above work performed was signed off (possibly by me). Everything was inspected; engine hoist; etc; were removed and we had to begin our other task on spoiler systems. I was informed about the incident over the phone; that some other technician and quality control inspector noticed improper installation of the l-hand top engine mount. I don't know what happened; possibly reinstallation of the l-hand top engine mount. I don't even exactly know what was found; what was installed improperly or poorly because I refuse to believe that mistake was made as per Q400 amm task. Finally; the work performed was inspected and found to be good. However; I think none of the parties involved can guarantee that after the installation; engine #1 mounts were not altered or reassembled. Supplemental information from acn 815050: in the hangar; me and mr X took a turnover from previous shift for the installation of the forward top engine mount. The side engine mount was already loose for us so we can get the top mount in place easily. Me and mr X begin installing the top mount first. We have to move the engine forward so we can top mount in place. After the top mount was in place; we move the engine hoist to get the bolt hole lined up with mount by using the engine hoist up and down to move the engine; but we couldn't get the hold lined up side-to-side and we drained the torque comparator and once we had done that; holes lined up. Once we got the bolt hole lined up; we put the mount together and put the bolt threw the hole to torque tight nut on the other side of the mount. Then we start tightening side mount and got the mount pin aligned with hole. We got the quality controller mr Y to see us torque top and side mount. We start with torquing the top mount first. I was on the forward side of the mount; holding with the wrench; keeping bolt from moving and mr X was torquing the nut. We torque the bolt but cotter pin hole didn't line up and then we start torquing side mount and cotter pin hole line up and cotter pin them. I got the new hardware; new nut and 2 washers and we start torquing; processing again for the second time on the top mount and we got mr Y to see us torque the nut and cotter pin hole line up and mr X did the cotter pin. Mr Y looked at the bolt and cotter pin of all 3 mounts. We start to service the torque comparator. This was the first time me and mr X did the forward engine mount. Lack of experience between both of us; and didn't verify the mount after torquing if installed correctly and didn't doublechk our work after we finished with our work. Callback conversation with reporter revealed the following information: reporter stated another mechanic and inspector later noticed the #1 engine forward top engine mount was not properly mated (seated) on one corner of the mount assembly. Although the mount bolt and nut had the proper torque; their installation had to be loosened up to allow the mount block to seat correctly and then be retorqued. They were working from a high lift vehicle and did not notice the unseated corner of the engine mount. Reporter stated he followed the task card; but realizes if he had used a mirror to look under the engine mount; he would probably have seen the unseated section of the forward mount. The torque comparator oil that was drained and reserviced; is a 5606 type fluid.
Original NASA ASRS Text
Title: TWO MECHANICS ARE INFORMED OF AN IMPROPER INSTALLATION OF A TOP; FORWARD ENGINE MOUNT FOR THE #1 ENGINE OF A DHC-8-Q400.
Narrative: NOV/08; C-CHK Q400; I WAS ASSIGNED TO ACCOMPLISH INSTALLATION OF THE TOP ENG MOUNT OF ENG #1 AND TO CONTINUED TENSION SPOILERS AFTER XA00 DUE TO 24-HR SOAKING TIME. SWING SHIFT TOOK A TURNOVER WITH WHO WE HAD TO PROCEED TO INSTALL THAT TOP ENG MOUNT. SINCE I HAVEN'T DONE INSTALLATION OF ENG MOUNTS DURING MY CAREER TIME IN ACR; I ASKED MY PREVIOUS SHIFT MECH TO BRIEF ME INTO IT VERBALLY; AND LATER WE USED Q400 AMM TASKS FOR INSTALLATION. ENG MOUNTS WERE INSTALLED AS PER Q400 TASKS; INSTALLATION LOOKED GOOD AND WAS INSPECTED BY OUR QUALITY CTL INSPECTOR X. YES; WE DID HAVE SOME HARD TIME DURING INSTALLATION; DUE MISALIGNMENT OF ONE OR THE OTHER ENG MOUNTS; BUT WE GOT IT ALIGNED; INSTALLED; TORQUED AND COTTER-PINNED AS PER Q400 AMM TASKS. ALL THE ABOVE WORK PERFORMED WAS SIGNED OFF (POSSIBLY BY ME). EVERYTHING WAS INSPECTED; ENG HOIST; ETC; WERE REMOVED AND WE HAD TO BEGIN OUR OTHER TASK ON SPOILER SYSTEMS. I WAS INFORMED ABOUT THE INCIDENT OVER THE PHONE; THAT SOME OTHER TECHNICIAN AND QUALITY CTL INSPECTOR NOTICED IMPROPER INSTALLATION OF THE L-HAND TOP ENG MOUNT. I DON'T KNOW WHAT HAPPENED; POSSIBLY REINSTALLATION OF THE L-HAND TOP ENG MOUNT. I DON'T EVEN EXACTLY KNOW WHAT WAS FOUND; WHAT WAS INSTALLED IMPROPERLY OR POORLY BECAUSE I REFUSE TO BELIEVE THAT MISTAKE WAS MADE AS PER Q400 AMM TASK. FINALLY; THE WORK PERFORMED WAS INSPECTED AND FOUND TO BE GOOD. HOWEVER; I THINK NONE OF THE PARTIES INVOLVED CAN GUARANTEE THAT AFTER THE INSTALLATION; ENG #1 MOUNTS WERE NOT ALTERED OR REASSEMBLED. SUPPLEMENTAL INFO FROM ACN 815050: IN THE HANGAR; ME AND MR X TOOK A TURNOVER FROM PREVIOUS SHIFT FOR THE INSTALLATION OF THE FORWARD TOP ENG MOUNT. THE SIDE ENG MOUNT WAS ALREADY LOOSE FOR US SO WE CAN GET THE TOP MOUNT IN PLACE EASILY. ME AND MR X BEGIN INSTALLING THE TOP MOUNT FIRST. WE HAVE TO MOVE THE ENG FORWARD SO WE CAN TOP MOUNT IN PLACE. AFTER THE TOP MOUNT WAS IN PLACE; WE MOVE THE ENG HOIST TO GET THE BOLT HOLE LINED UP WITH MOUNT BY USING THE ENG HOIST UP AND DOWN TO MOVE THE ENG; BUT WE COULDN'T GET THE HOLD LINED UP SIDE-TO-SIDE AND WE DRAINED THE TORQUE COMPARATOR AND ONCE WE HAD DONE THAT; HOLES LINED UP. ONCE WE GOT THE BOLT HOLE LINED UP; WE PUT THE MOUNT TOGETHER AND PUT THE BOLT THREW THE HOLE TO TORQUE TIGHT NUT ON THE OTHER SIDE OF THE MOUNT. THEN WE START TIGHTENING SIDE MOUNT AND GOT THE MOUNT PIN ALIGNED WITH HOLE. WE GOT THE QUALITY CTLR MR Y TO SEE US TORQUE TOP AND SIDE MOUNT. WE START WITH TORQUING THE TOP MOUNT FIRST. I WAS ON THE FORWARD SIDE OF THE MOUNT; HOLDING WITH THE WRENCH; KEEPING BOLT FROM MOVING AND MR X WAS TORQUING THE NUT. WE TORQUE THE BOLT BUT COTTER PIN HOLE DIDN'T LINE UP AND THEN WE START TORQUING SIDE MOUNT AND COTTER PIN HOLE LINE UP AND COTTER PIN THEM. I GOT THE NEW HARDWARE; NEW NUT AND 2 WASHERS AND WE START TORQUING; PROCESSING AGAIN FOR THE SECOND TIME ON THE TOP MOUNT AND WE GOT MR Y TO SEE US TORQUE THE NUT AND COTTER PIN HOLE LINE UP AND MR X DID THE COTTER PIN. MR Y LOOKED AT THE BOLT AND COTTER PIN OF ALL 3 MOUNTS. WE START TO SVC THE TORQUE COMPARATOR. THIS WAS THE FIRST TIME ME AND MR X DID THE FORWARD ENG MOUNT. LACK OF EXPERIENCE BTWN BOTH OF US; AND DIDN'T VERIFY THE MOUNT AFTER TORQUING IF INSTALLED CORRECTLY AND DIDN'T DOUBLECHK OUR WORK AFTER WE FINISHED WITH OUR WORK. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED ANOTHER MECHANIC AND INSPECTOR LATER NOTICED THE #1 ENGINE FORWARD TOP ENGINE MOUNT WAS NOT PROPERLY MATED (SEATED) ON ONE CORNER OF THE MOUNT ASSEMBLY. ALTHOUGH THE MOUNT BOLT AND NUT HAD THE PROPER TORQUE; THEIR INSTALLATION HAD TO BE LOOSENED UP TO ALLOW THE MOUNT BLOCK TO SEAT CORRECTLY AND THEN BE RETORQUED. THEY WERE WORKING FROM A HIGH LIFT VEHICLE AND DID NOT NOTICE THE UNSEATED CORNER OF THE ENGINE MOUNT. REPORTER STATED HE FOLLOWED THE TASK CARD; BUT REALIZES IF HE HAD USED A MIRROR TO LOOK UNDER THE ENGINE MOUNT; HE WOULD PROBABLY HAVE SEEN THE UNSEATED SECTION OF THE FORWARD MOUNT. THE TORQUE COMPARATOR OIL THAT WAS DRAINED AND RESERVICED; IS A 5606 TYPE FLUID.
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.