Narrative:

Given taxi instructions to taxi out of the ramp; Y4 right turn taxiway D to hold short on taxiway K and runway 15L for runway 15R. We complied with that clearance; then was given clearance to cross runway 15L to turn right onto taxiway C to hold short runway 15R. Taxiway C runs between the 2 parallel runways 15L/right. We crossed runway 15L without incident; made the turn onto taxiway C. Along taxiway C I realized I had not fastened my shoulder harness and that my harness was locked and could not work it loose. I instructed my first officer to continue to taxi the aircraft while I corrected the seatbelt issue. Once I had it corrected I assumed control of the aircraft just before the turn to runway 15R on taxiway C. Just as I resumed control of the taxi; we were cleared into position and hold runway 15R which was a left turn. I mistakenly turned right; however; to runway 15L; after the turn the controller queried us. I stopped immediately and we asked for clearance to taxi onto runway 15L then taxi down to taxiway K and back onto taxiway C for runway 15R. The controller asked us if we could depart runway 15L instead. We had already checked the takeoff data for both runways and knew we were legal for the departure and the departure clearance was a vector heading. With only minor modifications to the FMC (departure runway selected) required we accepted a runway 15L departure and departed without further incident. In the future I will secure my seatbelt and shoulder harness prior to taxi; or stop the aircraft to fix the issue; and finally I will verbalize and confirm all turns with my first officer before executing them. I feel that the second xfer of controls while receiving the 'position and hold' clearance distraction my first officer; not allowing him to catch my taxi error. So if I had given him the opportunity to confirm the turn verbally before executing it; we would not have had this incident. Also; from a design standpoint; I have noticed this locking mechanism to be a problem. If there were some type of detent added to send the shoulder harness into lock; this would be in the interest of safety.

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Original NASA ASRS Text

Title: A B747-400 CAPT TAXIED ONTO AN INCORRECT RWY AFTER BEING DISTRACTED BY A SHOULDER HARNESS ISSUE. HE LOST SA BEFORE RESUMING ACFT CTRL FROM THE FO.

Narrative: GIVEN TAXI INSTRUCTIONS TO TAXI OUT OF THE RAMP; Y4 R TURN TXWY D TO HOLD SHORT ON TXWY K AND RWY 15L FOR RWY 15R. WE COMPLIED WITH THAT CLRNC; THEN WAS GIVEN CLRNC TO CROSS RWY 15L TO TURN R ONTO TXWY C TO HOLD SHORT RWY 15R. TXWY C RUNS BTWN THE 2 PARALLEL RWYS 15L/R. WE CROSSED RWY 15L WITHOUT INCIDENT; MADE THE TURN ONTO TXWY C. ALONG TXWY C I REALIZED I HAD NOT FASTENED MY SHOULDER HARNESS AND THAT MY HARNESS WAS LOCKED AND COULD NOT WORK IT LOOSE. I INSTRUCTED MY FO TO CONTINUE TO TAXI THE ACFT WHILE I CORRECTED THE SEATBELT ISSUE. ONCE I HAD IT CORRECTED I ASSUMED CTL OF THE ACFT JUST BEFORE THE TURN TO RWY 15R ON TXWY C. JUST AS I RESUMED CTL OF THE TAXI; WE WERE CLRED INTO POS AND HOLD RWY 15R WHICH WAS A L TURN. I MISTAKENLY TURNED R; HOWEVER; TO RWY 15L; AFTER THE TURN THE CTLR QUERIED US. I STOPPED IMMEDIATELY AND WE ASKED FOR CLRNC TO TAXI ONTO RWY 15L THEN TAXI DOWN TO TXWY K AND BACK ONTO TXWY C FOR RWY 15R. THE CTLR ASKED US IF WE COULD DEPART RWY 15L INSTEAD. WE HAD ALREADY CHKED THE TKOF DATA FOR BOTH RWYS AND KNEW WE WERE LEGAL FOR THE DEP AND THE DEP CLRNC WAS A VECTOR HDG. WITH ONLY MINOR MODIFICATIONS TO THE FMC (DEP RWY SELECTED) REQUIRED WE ACCEPTED A RWY 15L DEP AND DEPARTED WITHOUT FURTHER INCIDENT. IN THE FUTURE I WILL SECURE MY SEATBELT AND SHOULDER HARNESS PRIOR TO TAXI; OR STOP THE ACFT TO FIX THE ISSUE; AND FINALLY I WILL VERBALIZE AND CONFIRM ALL TURNS WITH MY FO BEFORE EXECUTING THEM. I FEEL THAT THE SECOND XFER OF CTLS WHILE RECEIVING THE 'POS AND HOLD' CLRNC DISTR MY FO; NOT ALLOWING HIM TO CATCH MY TAXI ERROR. SO IF I HAD GIVEN HIM THE OPPORTUNITY TO CONFIRM THE TURN VERBALLY BEFORE EXECUTING IT; WE WOULD NOT HAVE HAD THIS INCIDENT. ALSO; FROM A DESIGN STANDPOINT; I HAVE NOTICED THIS LOCKING MECHANISM TO BE A PROB. IF THERE WERE SOME TYPE OF DETENT ADDED TO SEND THE SHOULDER HARNESS INTO LOCK; THIS WOULD BE IN THE INTEREST OF SAFETY.

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.