B777 CAPT AND DISPATCHER DISAGREE AS TO WHETHER AN FMS GENERATED DISPLAY CAN BE SUBSTITUTED FOR AN OTS VOR FOR A SPECIAL ENG FAIL PROC AT SFO.

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THE FLT WAS ORIGINALLY PLANNED WITH A TKOF GROSS WT OF 608.2 LBS. THE ARPT WAS DEPARTING ON THE RWY 28L/R. THE SFO VOR WAS OTS. THE 'ENG FAILURE ON TKOF' PROC (T-PROC) FOR RWY 28L/R IS PREDICATED ON A TURN AT 2 DME FROM THE SFO VOR TO INTERCEPT AND TRACK THE SFO 296 DEG RADIAL. THE SFO DETAILED PAGE LISTS AN ALTERNATE T-PROC TO USE IF THE SFO VOR AND DME ARE OTS. IT ALSO STATES; 'USE ACARS TKOF WTS DENOTED. USE THESE WTS WHEN SFO VOR OTS.' THE MOST FAVORABLE OF THESE WTS (28RO) LISTED A MAX TKOF WT ABOUT 6000 LBS LESS THAN OUR PLANNED TKOF WT. WHEN THE CAPT CONFERRED WITH DISPATCH; THE DISPATCHER STATED THAT A B777 COULD USE THE ORIGINAL WTS AND T-PROC BECAUSE THE T-PROC COULD BE FLOWN USING FMS AS A SUBSTITUTE FOR THE VOR. SHE REFED THE PARAGRAPHS ENTITLED 'NAVAID OTS' AND 'FMS NAVAID/WAYPOINT SUBSTITUTION' FOUND IN THE MANUAL. THE CAPT DISAGREED POINTING OUT THAT THE FIRST SENTENCE OF THE 'NAVAID OTS' PARAGRAPH SEEMS TO REQUIRE THAT AN ALTERNATE T-PROC BE FOLLOWED IF ONE IS PUBLISHED. THE PROB BECAME MOOT WHEN THE WT DROPPED ENOUGH AND THE HEADWIND INCREASED ENOUGH TO ALLOW A PACKS-OFF TKOF USING THE 28RO WTS. THE BASIC DISPUTE BTWN THE CAPT AND THE DISPATCHER ABOUT WHETHER THE ORIGINAL T-PROC CAN BE USED REMAINS UNRESOLVED. SINCE THE SFO VOR WILL BE OTS FOR SOME TIME; THIS PROB NEEDS TO BE RESOLVED QUICKLY.