Narrative:

I was called to ship XXX to assist a technician. When I arrived at the gate, he had the gear (landing) pinned and wanted to cycle the gear to check for a hydraulic leak (possible) on the center landing gear. There was not enough hydraulic fluid in the wheel well to justify concern but the crew now needed to be assured so I proceeded with the course of action. I asked the technician if the gear was properly pinned and he said yes. I saw the flags hanging from the pins in all gear. I went to the flight deck pwred hydraulics and raised the gear handle. The aircraft shuddered (unusual) and I immediately put the handle back down, depwred hydraulic, and went to investigate. The center gear pin he told me broke -- came out and the gear retracted and went back down when I had put it back down. It was not down and locked -- no hydraulic leak. Instructed the technician to depressurize the strut so we could get the gear down and locked. We got the gear locked, svced the strut, looked the gear over, determined no evidence of damage. I signed the aircraft off. Later I was notified the aircraft was not able to retract the center landing gear and was coming back. When the aircraft arrived, we looked at it again and saw no obvious damage. The next day, I was notified the retract actuator was bent, not allowing the gear to retract fully. In retrospect, if we had looked from the far side inside the wheel well we might have seen the actuator was bent. They believe it was bent when it was put back down on a loaded aircraft. If I thought there was any chance of a problem, I would have swapped aircraft and asked for a gear swing. The technician that pinned the gear was not thorough and too sure of himself. Next time I will check the pins myself. Callback conversation with reporter revealed the following information: the reporter stated when he arrived at the airplane the technician working the airplane advised the gear pins were installed. The reporter said the center gear pin is 36 inches in length and is inserted overhead in the wheel well and really difficult unless someone has received a little basic training. The reporter stated the maintenance manual illustration for the gear pin installation is worthless and does not show the precise holes to place the pin. The reporter said the technician working the job who inserted the pin has slightly more than 1 yr on the line is intelligent but displays overconfidence on the job. The reporter stated when the gear was pressurized and the handle raised it started to retract and the handle was quickly placed to extend. The reporter stated when the gear extended it bent the landing gear retract ram piston and was not observed by the technician. The reporter said the center landing gear lock pin was not installed correctly and fell out when the gear was pressurized in the retract position. The reporter said the airplane was dispatched and returned to the field due to unable to retract the center landing gear. The reporter stated the FAA has interviewed the reporter and the technician involved.

Related reports:

Google
 

Original NASA ASRS Text

Title: AN MD11 WAS DISPATCHED AND RETURNED DUE TO UNABLE TO RETRACT THE CTR LNDG GEAR. CAUSED BY DAMAGE TO THE GEAR ACTUATOR DURING MAINT.

Narrative: I WAS CALLED TO SHIP XXX TO ASSIST A TECHNICIAN. WHEN I ARRIVED AT THE GATE, HE HAD THE GEAR (LNDG) PINNED AND WANTED TO CYCLE THE GEAR TO CHK FOR A HYD LEAK (POSSIBLE) ON THE CTR LNDG GEAR. THERE WAS NOT ENOUGH HYD FLUID IN THE WHEEL WELL TO JUSTIFY CONCERN BUT THE CREW NOW NEEDED TO BE ASSURED SO I PROCEEDED WITH THE COURSE OF ACTION. I ASKED THE TECHNICIAN IF THE GEAR WAS PROPERLY PINNED AND HE SAID YES. I SAW THE FLAGS HANGING FROM THE PINS IN ALL GEAR. I WENT TO THE FLT DECK PWRED HYDS AND RAISED THE GEAR HANDLE. THE ACFT SHUDDERED (UNUSUAL) AND I IMMEDIATELY PUT THE HANDLE BACK DOWN, DEPWRED HYD, AND WENT TO INVESTIGATE. THE CTR GEAR PIN HE TOLD ME BROKE -- CAME OUT AND THE GEAR RETRACTED AND WENT BACK DOWN WHEN I HAD PUT IT BACK DOWN. IT WAS NOT DOWN AND LOCKED -- NO HYD LEAK. INSTRUCTED THE TECHNICIAN TO DEPRESSURIZE THE STRUT SO WE COULD GET THE GEAR DOWN AND LOCKED. WE GOT THE GEAR LOCKED, SVCED THE STRUT, LOOKED THE GEAR OVER, DETERMINED NO EVIDENCE OF DAMAGE. I SIGNED THE ACFT OFF. LATER I WAS NOTIFIED THE ACFT WAS NOT ABLE TO RETRACT THE CTR LNDG GEAR AND WAS COMING BACK. WHEN THE ACFT ARRIVED, WE LOOKED AT IT AGAIN AND SAW NO OBVIOUS DAMAGE. THE NEXT DAY, I WAS NOTIFIED THE RETRACT ACTUATOR WAS BENT, NOT ALLOWING THE GEAR TO RETRACT FULLY. IN RETROSPECT, IF WE HAD LOOKED FROM THE FAR SIDE INSIDE THE WHEEL WELL WE MIGHT HAVE SEEN THE ACTUATOR WAS BENT. THEY BELIEVE IT WAS BENT WHEN IT WAS PUT BACK DOWN ON A LOADED ACFT. IF I THOUGHT THERE WAS ANY CHANCE OF A PROB, I WOULD HAVE SWAPPED ACFT AND ASKED FOR A GEAR SWING. THE TECHNICIAN THAT PINNED THE GEAR WAS NOT THOROUGH AND TOO SURE OF HIMSELF. NEXT TIME I WILL CHK THE PINS MYSELF. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED WHEN HE ARRIVED AT THE AIRPLANE THE TECHNICIAN WORKING THE AIRPLANE ADVISED THE GEAR PINS WERE INSTALLED. THE RPTR SAID THE CTR GEAR PIN IS 36 INCHES IN LENGTH AND IS INSERTED OVERHEAD IN THE WHEEL WELL AND REALLY DIFFICULT UNLESS SOMEONE HAS RECEIVED A LITTLE BASIC TRAINING. THE RPTR STATED THE MAINT MANUAL ILLUSTRATION FOR THE GEAR PIN INSTALLATION IS WORTHLESS AND DOES NOT SHOW THE PRECISE HOLES TO PLACE THE PIN. THE RPTR SAID THE TECHNICIAN WORKING THE JOB WHO INSERTED THE PIN HAS SLIGHTLY MORE THAN 1 YR ON THE LINE IS INTELLIGENT BUT DISPLAYS OVERCONFIDENCE ON THE JOB. THE RPTR STATED WHEN THE GEAR WAS PRESSURIZED AND THE HANDLE RAISED IT STARTED TO RETRACT AND THE HANDLE WAS QUICKLY PLACED TO EXTEND. THE RPTR STATED WHEN THE GEAR EXTENDED IT BENT THE LNDG GEAR RETRACT RAM PISTON AND WAS NOT OBSERVED BY THE TECHNICIAN. THE RPTR SAID THE CTR LNDG GEAR LOCK PIN WAS NOT INSTALLED CORRECTLY AND FELL OUT WHEN THE GEAR WAS PRESSURIZED IN THE RETRACT POS. THE RPTR SAID THE AIRPLANE WAS DISPATCHED AND RETURNED TO THE FIELD DUE TO UNABLE TO RETRACT THE CTR LNDG GEAR. THE RPTR STATED THE FAA HAS INTERVIEWED THE RPTR AND THE TECHNICIAN INVOLVED.

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.