I just noticed strange FMC behaviour during my long distance trip. I have it programmed with ICAO step climb command, reflected in 'legs' page. MCP ALT is consequently set to target altitude (say, the highest altitude during the trip). The problem is that VNAV would not initiate ascent at appropriate moment, instead it just remains at original 'first altitude segment' altitude. To cut long story short, FMC would not initiate step-climb. When I noticed this very behaviour for extended time I attempted to manually adjust altitude by pressing FLCH to start ascent. It did, indeed reach target step-climb altitude of FL440, but to my amazement it went into ALT HOLD mode with SPD activated. Moreover, I could not re-engage VNAV mode to remain in accordance with FMC displayed data.I am interested, if anyone have experienced similar in the past and what was the cure.I tried to search the forum to find an answer, but found just one relevant question, however not replied to.I hope not to share this poster's fate. Please help me out.Thanks in advanceDon

http://www.avsim.com/cgi-bin/dcforum/dcboa...D43&archive=yeshttp://www.avsim.com/cgi-bin/dcforum/dcboa...D43&archive=yeshttp://www.avsim.com/cgi-bin/dcforum/dcboa...D43&archive=yesSome parts of those answers may have changed with the two patches but the general principle is the same; the aircraft DOES NOT execute step climbs automatically.BTW, if I'm not mistaken, the maximum cruising altitude for a Boeing 767-300ER in normal operations in 43,100 ft.

Thank you very much.It pays to search through old forum messages as well.All clear now. Still, I am not sure why is it, that I cannot re-engage my VNAV mode, after flying on FLCH.Don