"This guy is on his own, he's a test pilot"

A Vans customer wonders what to do next, and a 172 pilot asks if carb heat is really necessary all the way to the ground. Plus, the best spark plugs, and a vexing gear issue are on tap for Mike, Paul, and Collen this time. Email podcasts@aopa.org to be on the show.

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Full notes below:

Greg has a kit from Vans on order and he’s wondering what to do next. He can replace his quick build wing kit with the small cracks installed, but he wants to know if he should order replacements. Paul said when sheet metal work is done on certified aircraft in the field, a lot of cracks naturally come up. Greg said a customer has to agree to accept the modified terms of the new contract, and you have to either accept what they send you, or spend money on a second kit. Paul said to deburr as little as possible. The goal is clean, sharp corners, not a knife edge that can cut the rivet. Just barely touch the hole, he said.

Travis has an unusual gear problem. He was tasked with ferrying a Wheeler Express RG, an unusual experimental. On the ground the gear works perfectly, but when flying it won’t reliably retract. The system is based on a Glasair 3, and Colleen said the Glasair racers have a similar experience with their airplanes at Reno. On a ferry flight the hydraulic fluid built pressure over a few hours, and Travis had to select the gear down lever in order to release the pressure. Paul said not to spend any more time on the system, and replace it with something from Cessna.

Brian wants to get to the bottom of the fine wire and massive plug choice. His shop said he had to replace all 12 fine wire plugs at the last annual, all with around 800 hours on them. The shop recommended Temptest massives, which is what he did. He’s wondering if there’s really a difference in performance. Paul said fine wires tend to idle a little better and smoother. Corrosion was an issue on older Champion fine wires, which is what Brian had. And the ceramic is thicker on Tempest. Fine wires also last longer, usually long enough to cover the additional cost. Mike said they cost about four times as much, but last four times as long. He said some people also report smoother operation at very lean mixtures and small fuel economy improvements. Colleen has fine wire Tempests in her Cardinal but massives in her Skybolt. Her fine wires run a bit cleaner and don’t need to be gapped. Brian has seen a larger EGT differential when flying lean of peak with the massives.

Dennis has a 172 and he wants to know if it’s really necessary to keep carb heat on all the way to the ground. Mike said a newer Lycoming Skyhawk is less susceptible to carb ice, but his Continental O-300 is much more likely to produce ice. He recommends installing a carb heat gauge if he really wants to avoid having the carb heat on longer than necessary.