Hi all , good day 747-400 Locked on localizer for 34r KSEA set the approach on the autopilot to app . approach dosnt work , just get a fmc msg . nav invalid . Just updated to sp3 , real simple flight kpdx to ksea , like 83 nau miles , perfect approach . Also I tried to set the NAV/RAD Ils approach freq to 110.30 the localizer freq for 34r seattle ksea . nothing seems to work . Had this wonderful bird since april , haven't landed it the proper way once . Since I've been making Ils approaches and landings for some years now > I just wonder if it may be the nav data airac or somthing , Help !! Kevin , AMT

Probably outdated airac and/or sidstars. KSEA renumbered runways late last year. Runway 34R is still 34R but 34L became 34C... however, any glitch in the data usally makes the entire location unuseable.

Thanks Dan ; Time to update , what version do you recomend since the very newest may list 34c and flight sim 9 only knows 34l . Also I did get the big bird to capture the glide slope using NAV/RAD Page in FMC. Just plugged in the localizer 110.3 for 34r / 340 deg. Kevin AMT