Hi,i wondered if this is normal if not how do i rectify it?when im cruising at say 20000 feet i notice that my elevator trim keeps going from -2.9 through to -5.0 and then back again causing the plane to keep going up and downthis i feel is not normal!! what am i doing wrong?lee

Depends on a lot of things, what aircraft? What autopilot settings?Al

Hi Sorry for the lack of infoim flying the default 747-400i was using FD,AT both on (IAS set for 230kts) Nav set for EDSS via GPS, Vert speed 1400 FPM, Alt set for 20000, Auto pilot on-5.0 was set for take offthis may sound dumb but would it be anything to do with pitot heat being off ( cant remember what the outside temp was)cheerslee

Hi Sorry for the lack of infoim flying the default 747-400i was using FD,AT both on (IAS set for 230kts) Nav set for EDSS via GPS, Vert speed 1400 FPM, Alt set for 20000, Auto pilot on-5.0 was set for take offthis may sound dumb but would it be anything to do with pitot heat being off ( cant remember what the outside temp was)cheerslee

what's your weight? 230 kias is way too low for a 747-400 except without any load and only very little fuel!Sound more like the AP is fighting a stall.

what's your weight? 230 kias is way too low for a 747-400 except without any load and only very little fuel!Sound more like the AP is fighting a stall.

Hi the payload was 54341 kg Pass and Cargofuel at start flight was 22100 kgtrip fuel 12010 kgAll done with Topcat

5m0kin,I'm not sure exactly how the pax/cargo/fuel loads were configured for your flight, but I've experienced a similar problem with FSPassengers when there is either too much weight loaded forward or aft (out of CoG limits), and sometimes when speed is too low. It would appear that the default autopilot is unable to handle these non-standard conditions for flight, and so it begins to rock forwards and backwards as it attempts to maintain level flight.Just my two cents...

5m0kin,I'm not sure exactly how the pax/cargo/fuel loads were configured for your flight, but I've experienced a similar problem with FSPassengers when there is either too much weight loaded forward or aft (out of CoG limits), and sometimes when speed is too low. It would appear that the default autopilot is unable to handle these non-standard conditions for flight, and so it begins to rock forwards and backwards as it attempts to maintain level flight.Just my two cents...

Cheers for the reply,i think your right,just spent some more time going through the load sheet within Topcat and have done a couple of test flights and it seems fine now thanks for all your assistance guys.5m0kin