Mooney N9256V Landing Gear Woes

The first Mooneys that rolled off the assembly line in the late 1950s and early 1960s were equipped with a manually retractable landing gear. A large metal bar sticking up from the cockpit floor is directly connected to the tubes that move the wheels up and down. Starting in 1969, the year during which my Mooney was constructed, Mooney opted instead to use an electric motor to drive the landing gear. This decision had one major plus, in that sheer arm strength was no longer needed to move the landing gear, and one major minus, in that our arms are actually far more reliable than electric motors. (The manual gear was considered so reliable, in fact, that it remains to this day the only retractable gear ever certified by the FAA without a backup system.) Sure enough, in late October, 2007, the electric motor that had been driving my landing gear every flight for 38 years decided it was time to quit. To answer the most common questions I've received about this, yes, I was in the air when I learned that the gear would not automatically extend and yes, I cranked the gear down by hand before landing.

I brought the airplane to Brian Stout to determine the cause the gear motor malfunction. We eliminated the circuit breaker immediately, as it had been replaced earlier in the year, and the wiring tested as working. After jacking up the airplane, we were able to get the problem to recur after several gear cycles. The epiphany came when I accidentally jostled the motor while working under the plane, after which the gear extended. I removed the gear motor and actuator and sent the entire mess to George's Electrical in Sacramento, CA, a shop that was recommended by both Brian and by the Mooney email list for landing gear motor repair. Michael at George's rebuilt the motor to like-new condition (with Dukes out of business for many years, there is no such thing as new), while the actuator went to LASAR in Lakeport, CA, to be inspected. The found significant wear on the 20:1 ratio gears inside, so I opted to have them replaced with a set of upgraded 40:1 ratio gears. With these new gears, the landing gear would run retract and extend slower, but would incur less wear doing so. The two shops were able to complete their tasks and return the components fast enough that I was able to reinstall them by Thanksgiving.

Removing the landing gear motor requires that the plane be suspended in the air on jacks so that there is no weight on the landing gear.

Another angle of the airplane suspended on jacks in the maintenance hangar.

A shot taken at the beginning of the job, before removing the motor and actuator assembly.

My friend Keith came down to the airport for a bit to help pull the recalcitrant actuator out of the plane.

The actuator with its new gears and freshly rebuilt motor have been reinstalled and reconnected, ready to be tested.

With the landing gear working again, Brian Stout adjusts the gear rigging in order to ensure that the gear doesn't collapse.

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Version: 1.0 / December 16, 2007