alt hold problems

[theuglypigeon]

First of all, I love the 727. Everyday my pilot skills are becoming sharper because of it. Now for a little problem. When ever I turn on alt hold the 727 will shoot up sometimes 2000 feet before slowly descending back to the altitude I set it on in the first place. It seems regardless of how smooth of a level off I accomplish the plane will jump up 2000 feet and then eventually level off where I wanted it to. I'm not sure what I'm doing wrong, I hand fly the plane to cruise and thats when I enable alt hold.

Thanks for any help.
David

[Paul Golding]

As you've guessed, it's not supposed to act that way :-)

Are you engaging the AP during a climb and then quickly selecting alt hold, or flying by hand using control pressure to maintain pitch instead of trimming?

First check would be to take-off and level out at 5,000ft adjusting power and trim to be able to fly level and hands off, then engage the AP - at this piont you should still be flying level at a near constant speed - now engage alt hold ...... on the AP and not the FD controller on the glareshield.

Let me know what happens, and if it's bad, give me details of exactly what you were doing beforehand, weight, speed etc. Doing a forum search shows nobody else is having this happen so we just need to find out a bit more about how you're abusing our airplane :-)

[ToddNicholson]

Sounds like a trim issue. Level off manually at your desired altitude, then trim the aircraft for level flight using the trim wheel. Only after your trimmed for level flight, engage altitude hold.

If there is still a problem, it could be an issue with an old saved flight. Always start your flight by first loading the default flight, then switch to the 727.

[theuglypigeon]

Yep, its a trim issue. I trim the airplane for climb and I for some reason never thought about trimming for cruise. Thanks for the help.

Doing his best not to destroy the 727
David