On Stiff Mixture Control Arms

The saga comes to an end…I hope.

If you follow the helicopter-related posts in this blog, you may know that I’ve been having a problem with my helicopter’s mixture control. My usual interface with this device is the red knob with a button on my instrument panel. Push the knob to get fuel flowing. Pull the knob to shut down the engine. Don’t mess with the knob in flight.

Simple enough, until it got stiff and then broke. I wrote about it here and here.

Mixture Control ArmTurns out, the reason the mixture cable became fractured is because the mixture control arm (lavender in this image) on the fuel control was too stiff. When I pushed or pulled the mixture control in the cockpit it was buckling and fraying. Pushing it in may not have resulted in full rich fuel, which could result in the engine running hot and lead to even more problems.

Good thing we caught it!

Fuel ControlEd, Wickenburg’s very best airplane mechanic, followed up by pulling the fuel control and fixing it, following instructions of the device’s manufacturer in Wichita, KS. Here’s what it looked like sitting on his workbench with the offending arm removed for repair. This is a lot more of my helicopter’s innards than I usually like to see. But it was interesting to see the piece I’d found an illustration of for this blog (see above) in a place where it was clearly recognizable.

Ed has since put everything back together. I was busy yesterday with the Endurance Ride, so I didn’t fly. And I don’t want to bother Ed on a Sunday. But come tomorrow morning, I’ll be at the airport with the helicopter out on the ramp. I’ll start it up and Ed will likely look at everything from below as its running to make sure the mixture is indeed full rich. I’ll pull the mixture and he’ll watch it work. And then he’ll sign off on it.

And give me a bill. (Ah, the joys of aircraft ownership!)

Of course, if things don’t go as planned, you’ll likely read more about it here.

What do you think?