Selecting VNAV-----Above 3000' AGL (Boeing FCTM)
While in heavy traffic,or sometimes in bad weather,we select ap on as low as 500'. The ap engages in LVL CHG ,not in VS. At least on the 737.
We use VS when approaching cleared level,to avoid RAs..
Regarding acceleration altitude,well,not bellow 1000'.Depends on noise procedure,or airport characteristics.First select climb power,then flaps up speed.This will produce no less than 1000'/min ROC,while accelerating and retracting flaps.After clean configuration VNAV is selected (above 3000' AGL),the plane is accelerated at 250 kts,ROC >1000'/min ,in about 3-5 NM,after which it climbs with ROC 2500-4000'/min (depending of weight).
Last edited by alexban; 19th Apr 2006 at 07:17.