A B737-800 ON TKOF FROM A SHORT RWY AT V1. RIGHT SEAT PLT FLYING LOST ALL PRIMARY FLT DISPLAYS AND OTHER FMC/FMA FUNCTIONS.

Narrative

ON TKOF FROM A SHORT RWY IN VMC CONDITIONS APCHING V1 WITH A LINE CHECK CAPT FLYING FROM THE RIGHT SEAT; WE EXPERIENCED A LOSS OF THE FO'S PRIMARY FLT DISPLAY AND SEVERAL OTHER MODE CTL PANEL/FMC/FMA FUNCTIONS. ALSO LOST FLAP INDICATIONS; FLT DIRECTORS. CONTINUED TKOF AND CTL WAS TRANSFORMED TO THE LEFT SEAT. INSPECTOR RIDING THE JUMP SEAT HELPED US DETERMINE THAT THE SPARE LIGHT BULB HOUSING HAD FALLEN DOWN SNAGGING A CIRCUIT BREAKER ON THE P-6 PANEL.(CB # D-14 28V TRANSFER BUS 2 SECT 22). AFTER RESETTING THE CB; ELECTRICAL EQUIPMENT WAS RETURNED TO NORMAL. LUCKILY; THIS OCCURRED IN VMC CONDITIONS OR IT COULD HAVE BEEN A MUCH MORE SERIOUS CONDITION. I UNDERSTAND THAT THE DESIGN OF THE SPARE BULB HOUSING HAS BEEN A PROB ON THE B737-800 AND THE NEWER ACFT HAVE AN IMPROVED DESIGN. I BELIEVE THEY NEED TO RETROFIT THE OLDER MODELS OF THE B757-800 BEFORE THIS HAPPENS IN A WORSE SIT. UNTIL THEN; WE SHOULD EMPHASIZE THE NEED TO CHECK THE SECURITY OF THE SPARE BULB HOUSING BEFORE EACH FLT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED HE WAS IN THE CAPT'S SEAT DURING AN INITIAL OPERATING EXPERIENCE AND THE CHK CAPT WAS FLYING FROM THE R SEAT AND AN INSPECTOR WAS THE JUMPSEAT. THE RPTR SAID ON TKOF FROM A SHORT RWY AT V1 SPEED THE PLT FLYING LOST ALL PRIMARY INSTRUMENTS; MODE CTL PANELS AND FMC/FMA. THE RPTR STATED CTL WAS TRANSFERRED TO THE L SEAT AND THE TKOF CONTINUED. THE RPTR SAID IT WAS DISCOVERED THE SPARE BULB TRAY MOUNTED ON THE P-6 CIRCUIT BREAKER PANEL HAD FLOPPED DOWN TRIPPING CIRCUIT BREAKER D-14 28 VDC TRANSFER BUS 2 SECTION 2. THE RPTR STATED THE BREAKER WAS RESET AND ALL INSTRUMENTS AND DISPLAYS WERE NORMAL. THE RPTR SAID THE LATCH OR FASTENER USED ON THE SPARE BULB TRAY IS UNRELIABLE AND LATER MODELS OF THE B737-800 HAVE POSITIVE LATCHES.