Autopilot won't engage - sometimes

[Pod562 0]

I have posted this question on the PMDG forum but I am repeating it hear in case anyone with FS2Crew has experienced a similar problem.I have a frustrating intermittent problem engaging CMD A autopilot after take-off. This problem is only experienced with the PMDG 747. I have no problems with the PMDG 737.Having set-up the plane, including FMC, for T/O, after getting airborne, and with the FD, autothrottle, LNAV and VNAV enagaged, the autopilot CMD A will not enagage. Well, sometimes it will, and sometimes it won't but if you've spent an hour preparing for T/O and then find the whole flight has to be aborted because of this problem, it is very annoying.For the record:1. I have tried re-installing and without success.2. I have installed the updates.3. No other program is using the "A" keystroke.4. I have checked that the 747 is configured to use the "A" keystroke.5. I have FS2crew installed but I am sure the problem is unrelated to this program as it does not use the "A" keystroke.I have found that if I change planes, from the 747 to the 737 and then back again to the 747, I can then engage the autopilot.The problem with finding the cause is that the problem is intermittent but if anyone has experienced similar issue, I would be glad to hear from them.GrrggghhhRenzo

[Pod562 0]

I now think this may be something to do with my CP Flight MCP and the fact that it won't work with any "TAB" keyboard assignments. Anyone successfully used this bit of hardware with FS2crew?ThanksRenzo

[walfob 10]

I have a similar problem but prior to touchdown and performing a manual landing. I sometimes cannot disconnect the autothrottle and autopilot, which is more frustrating because it's at the end of the flight and I end up hovering a few feet above the runway before careering off the end. At about 100 feet above the runway I disenage autothrottle by right clicking on the TOGA screw, and disengage the autopilot by clicking on the disengage bar. Am I doing this correctly?Bernard

[byork 2,258]

Bernard,That sounds right.Run the FS2Crew Start Center and restore the original panel.cfg.FS2Crew won't load if you do that.See if you can reproduce it.Cheers,Bryan

[Guest flightsimrulesbrando]

Hey, I experience that problem on the rare occasion. It used to occur quite often a few months ago, but has only happened once in the last month. Like you, I would set up all the aircraft's systems for departure, and program the Takeoff Speeds, Runway, SID, set the Trim, Autothrottle, LNAV and VNAV, and correct flap setting, etc; yet when I got to 1000 feet AGL, I would not be able to engage the autopilot. I believe that when the problem occured often a few months ago, I noticed that each time I tried to connect the centre autopilot (or any of the autopilots), I would not be on an intercept heading to intercept the flight path as set out by the magenta line on the ND. If you are navigating in flight (with the Autopilot connected) using HDG SEL, and the aircraft is facing away from the magenta flight path and you activate LNAV, a message will pop up on the FMC saying that the aircraft is "NOT ON INTERCEPT HEADING," and the aircraft will continue to fly the heading as commanded by the HDG SEL bug. If, however, you turn the aircraft toward the flight path using the HDG SEL bug, and then activate LNAV, it will work. Now, back to the takeoff, I noticed that each time I tried to engage the autopilot and LNAV and it wouldnt work, I would be facing away from the Magenta flight path. (In those instances, I would fly the aircraft for a few minutes and then try to re-engage the autopilot and it would work - this is because I would have been vectored by ATC to turn toward the programmed flight path.) After making this realisation, on later flights, I began activating the autopilot only when the aircraft was set on a course to intercept the magenta flight path displayed on the ND. Thus, I believe that in order to activate the autopilot with LNAV selected after takeoff, you need to be on a heading to intercept the flight path of your SID or route. I hope that this solves your problem.

[byork 2,258]

That's a good point.If the FMC/Autopilot is not configured properly, things won't work.The test is to go into the VC and try it manually.If you can't make your desired autopilot selection in the VC, then your autopilot/FMC is not setup right.Remember that all FS2Crew does is literally send a key command (same one you could use) to get the FO to interface with the autopilot.Cheers,Bryan