Narrative:

On the above date I performed the second half of a takeoff warning operational check depicted as our company's work card, steps #40 through #54. It is still unknown whose signatures are in blocks #1 through #39, but it is common practice to do these steps when the aircraft is picked up at the gate. The reason for this is that it involves flap movements that are quicker to do during run-up. (This card is incorporated into a 'phase check' package of approximately 20-30 work cards.) and the reason for stopping at step #39 is because step #40 involves removing wires from a terminal board in the closet behind the pilot's seat just aft of the cockpit. Last night I was informed by the FAA and our chief inspector that the system failed some 7 days after the operations check was completed. I still don't remember when I performed the operations check after reinstalling the wire, but I do know I would not have signed off the operations check if it didn't work. I was also informed that when the system failed on the line, the #1 power lever would turn a light on and off in the lavatory and that the wire was installed in the wrong terminal block. Steps #40 through #47 involve removing 2 wires from 2 terminals, install 1 removed wire into the terminal of the other, and to do a quick operational check then to reinstall the wires into the original terminals. Step #48 has you recomplete steps #6 through #33 with all the operational checks involving flap movements, park brake position, elevator trim, and engine control unit rating selection. This step is to insure the wires were installed correctly. These steps are commonly performed on engine run in the morning, or so I was trained that way. I don't remember if I performed steps #6 through #33 with external hydraulic power or if I did it in the morning run. In any case, step #15 has you advance #1 power lever above flight idle +28 degrees, check for a horn sounding and return #1 power lever to the flight idle gate. Step #16 is to repeat #15 with #2 power lever. Steps #21, #24, #27, #30, and #33 have you repeat steps #15 and #16 after reconfiguring the condition of the aircraft between each step. Nowhere in the work card does it state that you cannot do steps #15 and #16 together, nor does it tell you what the removed wires are for. During engine run-up training I was always told to keep the power levers together to keep equal thrust on each engine. Last night during performing this task over for the FAA, I was informed that the wire I removed from terminal #6C was for the #1 power lever takeoff warning and that if I advanced both power levers at once it would give the same indication as if all the wires were installed correctly because the #2 power lever would sound the horn. This I did not know and if I had, I would have completed the operational check differently. The work card does not state that you could not do this check with engines running, it does not state what the wires are for, and it does not state that steps #15 and #16 have to be done independently. I only did as I was trained to do. Now that I know differently, I will not repeat these practices.

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Original NASA ASRS Text

Title: A DH8 WAS DISPATCHED WITH THE #1 ENG TKOF WARNING SYS WIRED INCORRECTLY RENDERING THE SYS INOP.

Narrative: ON THE ABOVE DATE I PERFORMED THE SECOND HALF OF A TKOF WARNING OPERATIONAL CHK DEPICTED AS OUR COMPANY'S WORK CARD, STEPS #40 THROUGH #54. IT IS STILL UNKNOWN WHOSE SIGNATURES ARE IN BLOCKS #1 THROUGH #39, BUT IT IS COMMON PRACTICE TO DO THESE STEPS WHEN THE ACFT IS PICKED UP AT THE GATE. THE REASON FOR THIS IS THAT IT INVOLVES FLAP MOVEMENTS THAT ARE QUICKER TO DO DURING RUN-UP. (THIS CARD IS INCORPORATED INTO A 'PHASE CHK' PACKAGE OF APPROX 20-30 WORK CARDS.) AND THE REASON FOR STOPPING AT STEP #39 IS BECAUSE STEP #40 INVOLVES REMOVING WIRES FROM A TERMINAL BOARD IN THE CLOSET BEHIND THE PLT'S SEAT JUST AFT OF THE COCKPIT. LAST NIGHT I WAS INFORMED BY THE FAA AND OUR CHIEF INSPECTOR THAT THE SYS FAILED SOME 7 DAYS AFTER THE OPS CHK WAS COMPLETED. I STILL DON'T REMEMBER WHEN I PERFORMED THE OPS CHK AFTER REINSTALLING THE WIRE, BUT I DO KNOW I WOULD NOT HAVE SIGNED OFF THE OPS CHK IF IT DIDN'T WORK. I WAS ALSO INFORMED THAT WHEN THE SYS FAILED ON THE LINE, THE #1 PWR LEVER WOULD TURN A LIGHT ON AND OFF IN THE LAVATORY AND THAT THE WIRE WAS INSTALLED IN THE WRONG TERMINAL BLOCK. STEPS #40 THROUGH #47 INVOLVE REMOVING 2 WIRES FROM 2 TERMINALS, INSTALL 1 REMOVED WIRE INTO THE TERMINAL OF THE OTHER, AND TO DO A QUICK OPERATIONAL CHK THEN TO REINSTALL THE WIRES INTO THE ORIGINAL TERMINALS. STEP #48 HAS YOU RECOMPLETE STEPS #6 THROUGH #33 WITH ALL THE OPERATIONAL CHKS INVOLVING FLAP MOVEMENTS, PARK BRAKE POS, ELEVATOR TRIM, AND ENG CTL UNIT RATING SELECTION. THIS STEP IS TO INSURE THE WIRES WERE INSTALLED CORRECTLY. THESE STEPS ARE COMMONLY PERFORMED ON ENG RUN IN THE MORNING, OR SO I WAS TRAINED THAT WAY. I DON'T REMEMBER IF I PERFORMED STEPS #6 THROUGH #33 WITH EXTERNAL HYD PWR OR IF I DID IT IN THE MORNING RUN. IN ANY CASE, STEP #15 HAS YOU ADVANCE #1 PWR LEVER ABOVE FLT IDLE +28 DEGS, CHK FOR A HORN SOUNDING AND RETURN #1 PWR LEVER TO THE FLT IDLE GATE. STEP #16 IS TO REPEAT #15 WITH #2 PWR LEVER. STEPS #21, #24, #27, #30, AND #33 HAVE YOU REPEAT STEPS #15 AND #16 AFTER RECONFIGURING THE CONDITION OF THE ACFT BTWN EACH STEP. NOWHERE IN THE WORK CARD DOES IT STATE THAT YOU CANNOT DO STEPS #15 AND #16 TOGETHER, NOR DOES IT TELL YOU WHAT THE REMOVED WIRES ARE FOR. DURING ENG RUN-UP TRAINING I WAS ALWAYS TOLD TO KEEP THE PWR LEVERS TOGETHER TO KEEP EQUAL THRUST ON EACH ENG. LAST NIGHT DURING PERFORMING THIS TASK OVER FOR THE FAA, I WAS INFORMED THAT THE WIRE I REMOVED FROM TERMINAL #6C WAS FOR THE #1 PWR LEVER TKOF WARNING AND THAT IF I ADVANCED BOTH PWR LEVERS AT ONCE IT WOULD GIVE THE SAME INDICATION AS IF ALL THE WIRES WERE INSTALLED CORRECTLY BECAUSE THE #2 PWR LEVER WOULD SOUND THE HORN. THIS I DID NOT KNOW AND IF I HAD, I WOULD HAVE COMPLETED THE OPERATIONAL CHK DIFFERENTLY. THE WORK CARD DOES NOT STATE THAT YOU COULD NOT DO THIS CHK WITH ENGS RUNNING, IT DOES NOT STATE WHAT THE WIRES ARE FOR, AND IT DOES NOT STATE THAT STEPS #15 AND #16 HAVE TO BE DONE INDEPENDENTLY. I ONLY DID AS I WAS TRAINED TO DO. NOW THAT I KNOW DIFFERENTLY, I WILL NOT REPEAT THESE PRACTICES.

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.