738 Autopilot

[Guest Devlin]

Hi,I have recently bought this fine aircraft, and although I seem to have grasped the fundamentals I have a problem with the Autopilot.Ok, Alt set, hdg set, FMC primed, take off roll, hit TOGA, reach Vrgear up. flaps retract, but then I cant arm the autopilot (cmd)or Lnav.Questions, then.Is there an altitude until which Autopilot/Lnav wont arm?Can I arm Autopilot on the ground?Am I missing something with the FMC? (I dont think so)CheersAndrew

[downscc 1,327]

The A/P won't engage until you are at least 400 ft AGL.. very realistic. The LNAV may arm on the ground if it has a "solution" to the first fix, but not VNAV.You didn't mention if autopilot was activating after initial climb is established (above 400AGL). Not sure if I answered your question.

[Qavion 19]

Andrew, did you see the message thread about engine generators?Cheers.Q>

[Guest Devlin]

Hi, thanks for your replies,Dan, yes you answered my question, 400ft agl sounds right, (plus a slightly slow processor)I was expecting to gear up then engage Autopilot, obviously the fact that I was probably below 400 ft would explain it.(cant remember reading that in the manual though, we should be told!)Thanks again.Andrew

[downscc 1,327]

You're right.. I was taught during my instrument training to hold runway heading until 400AGL by an instructor who used to be an ATC controller. He said that departures are designed to avoid obstacles only above that height, therefore, never start a turn until after that. This is how I came by the info.

[Guest Devlin]

QYes I have read it, thanks for the inforegardsAndrew