Originally Posted by
poldek77
Yes, I can.
LNAV - normally armed on the ground but I have flown some SIDs where it's not possible due to location of the 1st waypoint. According to OM-B:
Note: For LNAV to be armed on the ground, the departure runway must be selected and the course, to the first waypoint, must be within 5 degrees of the runway heading.
VNAV - my company allowed us to arm VNAV on the ground just last year so before that we used it after clean up. Nowadays armed for take-offs except noise abatement departures - some pilots prefer FLCH, others - VNAV+SPD INTV. On PF's discretion.
When selected on the ground, LNAV engage at 50ft, VNAV at 400ft.
The issue with VNAV armed on the ground is in the case of engine failure after V1. If you didn't carrefully select EO acc Alt on Take off page 2, it will level off and accelerate to VREF40 + 70 at 1000ft AGL. It could be hazardous expecially if you have high terrain in the vicinity