Stiffness in Elevator Control Circuit

[James Young]

Hello All,

Looking for a little advice. Just completed this years annual and my inspector is concerned with the stiffness in the elevator control.

It's always been heavy in pitch and there is a lot of sticktion when returning to the trimmed position.

The pushrod was disconnected behind the seat and I've pinned the problem to being somewhere aft of this connection. It seems there was a lot of force on the pushrod as it sprung up when disconnected.

It looks like it follows a series of guides into the tail and I suspect maybe it's rubbing on these.

Has anyone has a similar issue and if so what was the fix?

The aircraft is an ASW15 and is just coming up to its 3000hr inspection.

Cheers,
Jimmy

[Max-I]

Hello Jimmy,

only heard about an pushrod (J) in the front which scratched at the inside of the fuselage and had to be exchanged. But obviously you can exclude this failure in your case.

Presumably the drawings in the TM 21 and  TM22 on the Schleicher-Hompage http://www.alexander-schleicher.de/tm-lta-wa/tm-flugzeuge/asw-15-technische-mitteilungen/
could help you with the further investigation.

Disconnecting the pushrod, you mentioned, also at the rear end from the elevator-leaver, it is possible to check weather this pushrod has sticktion in the guides or the problem is above in the leverages of the elevator for example in the bearings. Better ask an experienced airplane technician or inspector at your place for advice before you try this. You might find an easier way or ore you can check with an Endoskop before removing major parts of the steering.

Anyway the problem sounds very much safety relevant and I would recommend to get it fixed previous to the next flight.

Please keep us updated

Yours, Max