I can't seem to reengage VNAV Path or VNAV SPD after proceeding past VNAV topd point with MCP set to a lower altitude. I (correctly) get ALT HOLD and SPD annunicated on the ADI. FLCH used to initiated decsent and whenever VNAV attempted, ALT HOLD and ALT CAPTURE occurs. Aircraft levels off even if outside a reasonable capture range with a very high R.O.D. Descent continued in FLCH. No digital or graphic VERTICAL TRACK ERROR info displayed on Progress Page 2 or ADI.Can any one assist?RegrdsAero767

HeyIt may be because you have no runway selected in the FMC. Try selecting an approach runway in the FMC next time. Without a valid runway selected for the approach, it has no way of knowing where you'll land, and thus can't calculate a T/D point. VNAV can't enter descent mode till it know's where you'll be touching down. I guess this is to remind the pilots to select a runway.

Thanks,I'll go and check that I did have a runway in the correct place. I should have thought of that. I think I did have one in but then again you know what 'Thought' did! Briefly, I'd built a non precision approach with a Missed Approach and a discontinuity between the last waypoint and the RW.P.S. The actual 767 VNAV decsent function dosen't behave in that manner , if a RW (with speed and crossing alt)isn't entered you just don't get a TD donut symbol (ie no arrival or approach entered).Thanks again!Aero767