AN ACR CAPT RPTS THE CREW TRACKING THE LOC TO THE INCORRECT RWY AT EGLL DUE TO FATIGUE FOLLOWING AN ALL NIGHT FLT.

Narrative

AFTER AN ALL NIGHT FLT TO EGLL; WE INTERCEPTED AND WERE TRACKING THE LOC TO THE WRONG RWY. THANKS TO AN ALERT CTLR; WE WERE DIRECTED TO THE CORRECT RWY FOR LNDG. I HAD BRIEFED THE RWY 27L APCH TO EGLL. RWY 27L WAS THE RWY ADVERTISED ON ATIS AND EVENTUALLY ASSIGNED BY ATC. WHEN PLACED ON VECTORS; THE FO ASKED IF I WAS READY TO HAVE THE LOC EXTENDED. I VERIFIED WHAT HE HAD IN THE FMC AND AGREED. WHAT I REMEMBER SEEING WAS THAT HE HAD LOADED AND EXTENDED THE LOC FOR RWY 27R. IT DIDN'T REGISTER THAT THAT WAS THE WRONG RWY. AS WE INTERCEPTED THE LOC FOR RWY 27R; THE CTLR CAME ON AND ASSIGNED A 240 DEG HDG TO COME BACK TO THE LOC. THE FO TOLD HER WE WERE JUST INTERCEPTING THE LOC (WHICH WAS TRUE BUT FOR RWY 27R). SHORTLY THEREAFTER; THE CTLR CAME BACK AND ASSIGNED A 245 DEG HDG TO INTERCEPT RWY 27L AND THEN WE WERE TRACKING RWY 27R. THE FO WAS STILL INSISTING WE WERE ON THE CORRECT LOC BUT I HAD FINALLY REALIZED OUR MISTAKE. WE REINTERCPTED AND LANDED ON RWY 27L. ALTHOUGH IT WAS AN ALL NIGHT FLT; I THOUGHT I WAS FUNCTIONING WELL DURING THE ARR TO EGLL. I NOW REALIZE THAT FATIGUE PLAYED A BIG FACTOR IN OUR CREW ERRORS. I PERSONALLY HAD MISSED OUT ON PLANNED REST BEFORE THE TRIP AND DID NOT REST WELL DURING MY BREAK; IN SPITE OF HOW TIRED I WAS. I DIDN'T VERIFY THE FREQ IN THE NAV/RAD PAGE; WHICH I TRY TO INCORPORATE IN MY BRIEFING TO VERIFY THE CORRECT RWY IS LOADED INTO THE FMC. NUMEROUS OPPORTUNITIES TO DISCOVER THE ERROR WENT UNNOTICED DUE TO OUR FATIGUE.