A DC10-30 FREIGHTER PIC EXPERIENCES A HDG TRACK DEV ON DEP FROM RJAA ARPT. THE NRT DEP CTLR QUESTIONS HIM REGARDING THE HDG DEV. DEP WAS BASED UPON NOISE ABATEMENT.

Narrative

ON APR/XA/98 AT APPROX XA02 LCL; TKOF HAD JUST BEEN MADE FROM RWY 16 NEW TOKYO INTL ARPT (RJAA); JAPAN; AND THE 'PAPAS 5 DEP' WAS BEING FOLLOWED IN CLR WX AND EXCELLENT VISIBILITY. THE DEP; FROM TKOF; PROCEEDS RWY HDG TO THE 'YQ' NDB (5.5 DME NRT); THEN THE 156 DEG YQ TO 12.0 DME NRT; THEN L TURN TO INTERCEPT THE 140 DEG RADIAL OFF NRT TO PAPAS INTXN. AT THE YQ NDB THE CAPT BEGAN TO DIRECT THE CLEAN-UP OF THE DC10'S FLAPS AND SLATS AT 3000+ FT AGL WHEN THE FO SAID; 'THERE'S 5.5 DME; READY TO TURN L; IS 120 DEG HDG TO INTERCEPT OK?' I (CAPT) FELT A MOMENT OF CONFUSION; THINKING THAT WE WERE TO FLY BEYOND THE NDB BEFORE TURNING L; BUT RECALLED THE 5.5 DME REF AND HAVING MY HANDS FULL OF RETRIMMING THE JET AND ACCELERATING; FIGURED THE FO MUST BE REFERRING TO HIS SID PAGE BUT I WAS MISTAKEN; SO I TURNED L AND BEGAN THE 140 DEG RADIAL INTERCEPT. SHORTLY THEREAFTER; DEP CTL ASKED IF WE WERE TURNING TO INTERCEPT THE 140 DEG RADIAL; AND THEN SAID THE NEXT TIME TO TURN AT 12.0 DME. WE REALIZED OUR MISTAKE -- CUEING ON THE 5.5 DME REF OVER THE YQ NDB AND THINKING WE HAD REACHED THE TURN POINT. I; AS PF; SHOULD HAVE INSTEAD CUED IN ON MY CONFUSION AS A WARNING; TAKEN THE TIME TO RECHK THE SID PAGE AND THEN TAKEN APPROPRIATE ACTION. THE CTLR DID NOT SEEM TO BE OVERLY CONCERNED WITH THE DEV. HOWEVER; THE AREA IS VERY NOISE SENSITIVE. SUPPLEMENTAL INFO FROM ACN 399336: I; AS SO; AM NOT GIVEN A SET OF APCH/DEP PLATES AND SO HAVE NO REF DATA. ALSO; I WAS NOT INCLUDED IN THE DEP BRIEFING AS I WAS CLOSING UP THE FLT. I SHOULD HAVE ASKED TO LOOK AT THE SID MYSELF; SO AS TO BETTER BACK UP THE FRONT END CREW.