Hello all, I have been flying the 800 with all the relevant keyboard/PMDG commands with no problems. However, yesterday I changed to the 900 and loaded a flight and tried to load the LNav on the ground without success, I carried on and took off, engaged VNav and A/Pilot and only then did LNav take effect. I was under the impression that Boeing permitted activation of LNav on the ground or is the 900 an exception. Thanks in advance. richard welsh.

The first way point must be within 5° of runway heading for LNav to arm on the ground.

Also, sometimes people forget the obvious ! You must have an active route in the CDU !!! Fred.