Gear doors not closing on gear extension.

[hharney]

Originally Posted by AV8ing

We've got a D Model (engine driven hydraulic pump) and the gear doors are not closing on gear extension.

Ground test: battery off, hand pumps gear doors open - battery switch on, hand pumps doors closed, checks ok.

Any ideas on troubleshooting this ?

Thanks!

Sounds like it's in the microswitch loop. It's daisy chained so any open connection will not allow the doors to close. Check all the micro switches and inspect each connector very carefully. A loose connection on a terminal or broken wire are sometimes hard to see.

[B2C2]

I had this issue as well when I first bought my T337D skymaster. The switches would close on the ground after following the manual procedure for setup but not in the air. The issue is that the airflow over the back of the plane in flight creates negative pressure that forces the gear away from the switches. If these don't all close the gear doors won't close either. A slightly more aggressive adjustment on the switch position fixed the problem. I haven't had it since. One other issue I have consistently is that the hydraulic mule used to swing the gear on the ground would suck hydraulic fluid out on shutdown. So every year I remind the A&P to top up the fluid after annual.

[Kim Geyer]

Had this problem with our E model years ago and it was the handle switch on the bottom of the power pack