My memory must be going !!I'm sure not too long ago that somewhere in the FMC I was able to put in an extended centreline. I can't sem to bring this up now, I end up creating a waypoint using the ILS frequency which works OK, but I'm just baffled as to where the RW Ext option has gone. Did it disappear when I upgraded to the 800/900 series?

I'd have to load the NG up to check for sure, but provided you didn't actually select an IAP, the runway extension point entry should appear below the runway after you select it. (just the runway, not an approach!)

How do u create a wpt using the ILS frequency?Paul

Paul,Now you ask I'm not sure that I did - maybe I created a waypoint using the airfield NDB or VOR frequency. I'm at work so will have to check one night this week, (sorry if you know this already) but certainly creating a place/bearing waypoint is easy and well documented in the FMC Manual.

whats the purpose of the runway extension in the FMC? It is used to guide the pilots into the runway when there is no ils i.e a purely VOR approach?

It is useful for giving guidance on visual approaches.CheersSteve

I find the rwy ext fix useful for visual approaches where I plan to enter a base leg. I put the rwy ext fix at 3 nm with an altitude constraint of 1000 ft agl. Just used it last night going into KJAN.In a relatively heavy 737, my entry was a right base to 16R (coming from the West) with LNAV & MCP SPEED control but using VS for descent. I slowed to 210 kts about 10 nm out, 160 kts at about 5 nm and added flaps to 5 as she slowed. I let LNAV make the turn at the rwy ext fix to a 3 nm final, check my position relative to the runway and since it looked good, slowed to 140 with gear and 15 flaps. As soon as landing was assured I hung out 40 flaps and turned off the AP and used autothrottle with handfly to the runway at Vref+5. If anything, I was a little high over the threshold but it worked pretty good.

. . . and ND range at 5?

Another way you guys can get an extended centerline is to use the FMC fix page and enter in the localizer as the fix. So going into my home airport, KTUS, I could enter in ITUS, the 11L localizer, set it to draw the 303 radial (reciprocal of the runway heading, 123) and I'll get an infinite line along the runway on the ND...