Vnav does not engage on the ground B737NG
Hello,
Has anyone came across the issue where VNAV cannot be selected on the ground, and only when airborne above 1000AGL?
I thought there was a service bulletin on it, but its referring to Update 10.7.
The aircraft from what I have been told has Update 12.0 installed. LNAV also drops out on the take off roll but can be reengaged.
I dont have access to MyBoeing Fleet personally, but if anyone could shed some light on the subject or the bulletin (if there is one) number that would be great.
Cheers.