No Flying this Weekend

It could be worse.

Robinson Mixture ControlThe other day, I reported a mechanical problem with my helicopter. In summary, the mixture control had been kind of stiff and it made a weird noise when I pulled it out. When my mechanic attempted to lubricate it, the mixture cable snapped.

The photo here shows a Robinson Raven II instrument panel very similar to mine. I’ve circled the mixture control. Remember: push in to allow fuel flow, pull out to stop fuel flow. Airplanes have similar controls. Airplane pilots adjust this in flight — that’s called leaning the engine. Helicopter pilots generally do not do this. It’s either in and the engine is running or out and the engine is stopped.

I didn’t make a big deal out of it then because it seemed to be a simple enough fix. We ordered the replacement cable from the factory and I figured that Ed, my local mechanic, would get that sucker installed not long after it arrived.

The more amazing thing to me — at least at the time — is that I’d proactively found and set about resolving a minor mechanical problem before it got me stranded somewhere inconvenient. The timing couldn’t have been better. The day before, I’d written an article for HeliNews about that exact topic. I was pleased that I’d learned a lesson.

Mixture Control SchematicWell, things are never as easy as they should be. Ed got the cable and went to work installing it. He soon ran into problems. The cable wouldn’t move smoothly. It wouldn’t go in all the way. He’s pretty sure we’ll have to order the entire cable assembly today. (This image, taken from Robinson SB-55, shows where the mixture cable attaches to the fuel mixture control. I highlighted the cable and its sheath in red. We ordered just the cable and it is apparently having trouble moving in the original sheath.)

Today is Friday. Although they could overnight the part for Saturday delivery, Ed doesn’t normally work on Saturdays. So I’ll save a few bucks on shipping and get it delivered Monday. With luck, it’ll be just what Ed needs and he can install it then.

Until it’s installed, there’s no flying for me.

But that doesn’t seem to matter much. I have no flights scheduled for this week and I have plenty of writing work to do. (I’m developing my third course for Lynda.com and have an open request for short how-to articles to fill for one of my publishers.) This weekend, I’m volunteering at the annual Land of the Sun Endurance Ride by marking horse butts with numbers, making my famous vegetarian bean soup, and timing in the 50-milers at the 25-mile manditory break. It’s almost a good thing that the helicopter is down for maintenance; less of a distraction for me.

I do want it running soon, though. Murphy’s Law of helicopter charter operations states that the most calls for your service will come in when you’re least able to meet customer needs. It must be a sign of the economy that my phone hasn’t started ringing off the hook yet.

2 thoughts on “No Flying this Weekend

  1. Maria,

    I love to read your blogs…especially about flying. Just read the cable problem and Keith says, “Often times a stiff mixture control starts with a sticky mixture shaft. Make sure your mixture operatures very smoothly, if not, remove your fuel control assembly, and have a service facility clean the shaft and housing.

    Whenever a cable goes bad…you always change the housing”

    So good work! says Deb

    • I’m not sure if he replaced the housing for the mixture control knob. In fact, I don’t think he did. And he didn’t replace the sheath that goes around the cable. He just replaced the broken cable and fixed the mixture control arm on the fuel control so it moved smoothly again. I’ll talk to him about the housing today; maybe we’ll order one and have it standing by at the first sign of a repeat problem. Thanks for this input. This is one of the reasons I prefer having the aircraft worked on more often by an experienced Robinson mechanic. They know all the little Robinson things. Ed’s a great airplane mechanic and I sent him to the Robinson maintenance course, but he doesn’t know Robinson-specific secrets and issues. The factory, however, was familiar with the control arm issue; it’s evidently related to the fuel control reorientation that was required a few years back. Keith would know all about that, too.

What do you think?