Narrative:

Inadvertently retracted nose gear on a boeing 737-300 aircraft while performing an operational check on an aircraft system during maintenance. Gear retracted due to the removal of the gear pin locks by the previous maintenance crew, and by me not physically checking the gear area before placing the gear handle into the up position after taking over the maintenance operation. Failure to perform each step of the operational check and physically checking that the gear pins were not removed by someone else before accomplishing the procedure. Boeing 737- 300 arrived with 'B' system hydraulic failure and loss of hydraulic fluid. Replaced engine driven hydraulic pump, changed filters, ran engines and all aircraft hydraulic system including pinning the landing gear and operating gear lever up and down with no fluid loss found. Maintenance crew could not find any fluid loss and therefore would not release the aircraft for service. I took over the trouble-shooting of the aircraft system and replaced a computer card and a landing gear transfer valve. Parts of the operational checks which failed prior to the valve change passed per the maintenance manual check and upon completion of the checks and because fluid lines to the landing gear had been opened, I wanted to verify positive pressure on the down locks of the gear and cycled the gear handle to accomplish this. Upon raising the gear handle the aircraft nose settled onto the ramp, damaging the nose gear doors. The previous maintenance crew removed the gear pins prior to leaving even though the aircraft was not released for service. My failure to physically check the gear to be sure the gear pins were still installed caused the incident.

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Original NASA ASRS Text

Title: RPTR ERROR ADMITTED IN RAISING GEAR HANDLE AND NOT INSURING THAT THE GEAR PINS WERE IN PLACE. ACFT DAMAGED.

Narrative: INADVERTENTLY RETRACTED NOSE GEAR ON A BOEING 737-300 ACFT WHILE PERFORMING AN OPERATIONAL CHK ON AN ACFT SYS DURING MAINT. GEAR RETRACTED DUE TO THE REMOVAL OF THE GEAR PIN LOCKS BY THE PREVIOUS MAINT CREW, AND BY ME NOT PHYSICALLY CHKING THE GEAR AREA BEFORE PLACING THE GEAR HANDLE INTO THE UP POS AFTER TAKING OVER THE MAINT OP. FAILURE TO PERFORM EACH STEP OF THE OPERATIONAL CHK AND PHYSICALLY CHKING THAT THE GEAR PINS WERE NOT REMOVED BY SOMEONE ELSE BEFORE ACCOMPLISHING THE PROC. BOEING 737- 300 ARRIVED WITH 'B' SYS HYD FAILURE AND LOSS OF HYD FLUID. REPLACED ENG DRIVEN HYD PUMP, CHANGED FILTERS, RAN ENGS AND ALL ACFT HYD SYS INCLUDING PINNING THE LNDG GEAR AND OPERATING GEAR LEVER UP AND DOWN WITH NO FLUID LOSS FOUND. MAINT CREW COULD NOT FIND ANY FLUID LOSS AND THEREFORE WOULD NOT RELEASE THE ACFT FOR SVC. I TOOK OVER THE TROUBLE-SHOOTING OF THE ACFT SYS AND REPLACED A COMPUTER CARD AND A LNDG GEAR TRANSFER VALVE. PARTS OF THE OPERATIONAL CHKS WHICH FAILED PRIOR TO THE VALVE CHANGE PASSED PER THE MAINT MANUAL CHK AND UPON COMPLETION OF THE CHKS AND BECAUSE FLUID LINES TO THE LNDG GEAR HAD BEEN OPENED, I WANTED TO VERIFY POSITIVE PRESSURE ON THE DOWN LOCKS OF THE GEAR AND CYCLED THE GEAR HANDLE TO ACCOMPLISH THIS. UPON RAISING THE GEAR HANDLE THE ACFT NOSE SETTLED ONTO THE RAMP, DAMAGING THE NOSE GEAR DOORS. THE PREVIOUS MAINT CREW REMOVED THE GEAR PINS PRIOR TO LEAVING EVEN THOUGH THE ACFT WAS NOT RELEASED FOR SVC. MY FAILURE TO PHYSICALLY CHK THE GEAR TO BE SURE THE GEAR PINS WERE STILL INSTALLED CAUSED THE INCIDENT.

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.