Throttled

After the airplane was returned to me, my gut was telling me something was wrong. Some of the work was, in short, a bit sloppy. I took this as a sign to go over everything, including 10 hours of high-speed taxi tests before the first flight, but clearly it wasn't enough. I recall looking at the throttle and how unprofessional it looked, in particular, "full throttle" on the right side only opened the throttle to 75 percent. The left seat throttle lever opened and closed the carbs fully, so I decided I could live with it.

Editorial Staff

Thursday, October 03, 2019 at 12:00 AM ET

Verified

Key Takeaways:

The author's decision to upgrade a light sport plane's engine led to a problematic throttle relocation, which introduced design flaws and sloppy workmanship.
During the second flight, the modified throttle system malfunctioned upon landing, causing the engine to unexpectedly accelerate and forcing the pilot to execute a ground loop to stop the plane.
The incident highlighted the dangers of deviating from factory designs, not thoroughly vetting modifications, and ignoring warning signs of substandard work, with the author ultimately taking responsibility for complicating the aircraft.

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Ipurchased a popular light sport that had been sitting in a hangar after the builder injured his back. We both walked away happy with the sale, but I soon decided it needed an engine with more horsepower. I worked with an A&P and builder to coordinate the engine upgrade, and we agreed on a number of other projects, one of which involved relocating the throttle.

This was my first mistake, not leaving well enough alone. Clearly the factory knew a simple, foolproof throttle easily reached by both pilots was the way to go. Fabricating a dual-throttle so both pilots can fly with one hand on the stick and the other on the throttle ended up introducing problems that didn’t exist before.