Narrative:

Aircraft X ferried into ZZZ on jul/tue/06 at approximately XA00 with a #1 main landing gear forward gear door amber light illuminating in flight write-up. I was asked to check the pseu for codes when the aircraft entered the hangar. After power was applied; I moved the power levers forward to supply power to the pseu for testing. At that time the horn for takeoff warning sounded; due to the parking brakes being set. It required pulling the circuit breaker to stop the horn. I then proceeded to retrieve the codes from the pseu. Once this was done; I proceeded to help with getting the aircraft on jacks to troubleshoot the landing gear problem. Once the aircraft was on jacks; I volunteered to situation in the cockpit to man the landing gear control handle. Once instructed to raise the landing gear; I raised the handle; causing the landing gear horn to sound. I then proceeded to pull the circuit breakers for landing gear horn so I could communicate with the ground personnel. I also pulled the hydraulic xfer circuit breaker so the ptu would not come up while the gear swung. The gear swings; troubleshooting; and repair of the landing gear door continued for an hour. In the meantime I was asked to look at the nose landing gear steering system; which was also MEL'ed; to see if I could see anything obvious. At this point I never returned to the cockpit for the duration of the aircraft's visit into the hangar; getting involved with different aspects of maintenance. The aircraft was removed from jacks; towed to the flight line; parked; and prepped all without anyone checking for circuit breakers being pulled. At this point; 3 breaker takeoff warning; landing gear horn; hydraulic power xfer were pulled.

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Original NASA ASRS Text

Title: A DHC8-100 WAS RETURNED TO SVC AND OPERATED 1 FLT WITH HYD PWR XFER; TKOF WARNING AND LNDG GEAR WARNING HORN CIRCUIT BREAKERS PULLED AND NOT RESET.

Narrative: ACFT X FERRIED INTO ZZZ ON JUL/TUE/06 AT APPROX XA00 WITH A #1 MAIN LNDG GEAR FORWARD GEAR DOOR AMBER LIGHT ILLUMINATING IN FLIGHT WRITE-UP. I WAS ASKED TO CHECK THE PSEU FOR CODES WHEN THE ACFT ENTERED THE HANGAR. AFTER PWR WAS APPLIED; I MOVED THE PWR LEVERS FORWARD TO SUPPLY PWR TO THE PSEU FOR TESTING. AT THAT TIME THE HORN FOR TKOF WARNING SOUNDED; DUE TO THE PARKING BRAKES BEING SET. IT REQUIRED PULLING THE CIRCUIT BREAKER TO STOP THE HORN. I THEN PROCEEDED TO RETRIEVE THE CODES FROM THE PSEU. ONCE THIS WAS DONE; I PROCEEDED TO HELP WITH GETTING THE ACFT ON JACKS TO TROUBLESHOOT THE LNDG GEAR PROB. ONCE THE ACFT WAS ON JACKS; I VOLUNTEERED TO SIT IN THE COCKPIT TO MAN THE LNDG GEAR CTL HANDLE. ONCE INSTRUCTED TO RAISE THE LNDG GEAR; I RAISED THE HANDLE; CAUSING THE LNDG GEAR HORN TO SOUND. I THEN PROCEEDED TO PULL THE CIRCUIT BREAKERS FOR LNDG GEAR HORN SO I COULD COMMUNICATE WITH THE GND PERSONNEL. I ALSO PULLED THE HYD XFER CIRCUIT BREAKER SO THE PTU WOULD NOT COME UP WHILE THE GEAR SWUNG. THE GEAR SWINGS; TROUBLESHOOTING; AND REPAIR OF THE LNDG GEAR DOOR CONTINUED FOR AN HR. IN THE MEANTIME I WAS ASKED TO LOOK AT THE NOSE LNDG GEAR STEERING SYS; WHICH WAS ALSO MEL'ED; TO SEE IF I COULD SEE ANYTHING OBVIOUS. AT THIS POINT I NEVER RETURNED TO THE COCKPIT FOR THE DURATION OF THE ACFT'S VISIT INTO THE HANGAR; GETTING INVOLVED WITH DIFFERENT ASPECTS OF MAINT. THE ACFT WAS REMOVED FROM JACKS; TOWED TO THE FLT LINE; PARKED; AND PREPPED ALL WITHOUT ANYONE CHKING FOR CIRCUIT BREAKERS BEING PULLED. AT THIS POINT; 3 BREAKER TKOF WARNING; LNDG GEAR HORN; HYD PWR XFER WERE PULLED.

Data retrieved from NASA's ASRS site as of January 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.