Mark R. Twombly is an aviation writer residing in Florida and is the co-owner of a Piper Twin Comanche.
"How I spent my summer vacation." It's been a very long time since I wrote an English paper on that subject. If I had to write one today it would be for language arts since English class no longer exists, and it wouldn't be much concerned with vacation because there was precious little of that in my summer. A few days with the family in New York State's Finger Lakes wine-making region, including a visit to the Baseball Hall of Fame in lovely little Cooperstown, was about the extent of it. Most of the rest of my summer was spent in heavy R&R.
Not R&R as in rest and relaxation, but as in rebuild and rejuvenate. I wasn't the one getting rejuvenated, however — the R&R was for the airplane.
It began last May with a trip to Zephyr Engines in Zephyrhills, Florida. We were facing a deadline to comply with a longstanding airworthiness directive to replace the oil pump impellers on our Textron Lycoming IO-320 engines. I knew Zephyr President Charlie Melot from past dealings and, like me, he is a partner in a Piper Twin Comanche. Who better to handle the assignment?
The work is more complicated than it sounds. Removing the oil pump requires removing the engine from its mount. We knew the project would be expensive, especially since we had some additional squawks and action items, including installing new engine vibration dampers. But it had to be done. The FAA said so.
I'm certain a rule-of-thumb formula exists to ballpark the cost of engine work — something improbably, uncannily accurate like 5.5 times engine displacement minus the horsepower rating for any major work up to replacing more than one cylinder, at which point it goes to 10 times displacement plus horsepower rating. And, in fact, we might have come in at a price close to that formula had it not been for the mechanic's noticing the glint and gleam of chunky metal particles caught in the oil drain screen on the right engine.
When the call came from Melot, it was obvious the news was bad. His voice was edgy and nervous, like a doctor who suddenly discovers a troubling problem in a patient who is in for a routine procedure.
"Might be serious, might not," he said, unconvincingly. "It's possible the metal has been there for a while if the screen has not been cleaned. If it's recent, well…." He let the unfinished sentence hang ominously. "It may be wear from a piston pin. If that's the case it might require a new cylinder, but that should do it."
Work on the impeller stopped while the shop removed cylinders looking for telltale wear on the suspect pins. The next time Melot called, his voice was dull and monotonic. That troubling problem the doctor had discovered? It turned out to be terminal.
"The metal is from the crank bearing," the good doctor reported. "Plus, one cylinder is about done with. We can put it all back together if you want. You might get another 200 hours out of it, but…." Another unfinished sentence, another uncomfortable silence.
The choice was clear. The right engine has been cantankerous all along — two of four cylinders have had to be replaced in the last 400 hours, along with the fuel pump and fuel servo. With just a few hundred hours left until TBO, it made no sense to continue on life support. Six weeks later, we had a fully compliant left engine and a freshly overhauled right engine, both sweetly smooth and strong.
We enjoyed a few short weeks of flying behind the engines before the airplane was taken out of service once again, this time for its annual physical. Switlik Aviation, the shop at my home base, had seen the airplane before for oil changes and to correct minor aches and pains, but never for an annual inspection. I assured the head physician, Edd Switlik, that the engines had just been examined extensively and we knew of no significant airframe or system problems, so it should be a routine inspection.
In retrospect, Edd might have taken that statement as a challenge. Edd and his boys have a reputation in these parts for being thorough, which is just what you want in an aircraft maintenance shop. We got it, too. Ten days after turning it over to Switlik, we were reviewing a multipage list of squawks that had been overlooked or ignored in the past. We couldn't argue with a single item, either. Before the annual we assumed, probably incorrectly, that the airplane was in relatively good health throughout; now it truly is.
Following the white-glove annual, we got in two more weeks of flying before parking the airplane yet again, this time at a paint shop. As I write this, Pam and Greg at R&B in Topeka, Kansas, have been stripping, sanding, etching, and priming it for about four weeks. The Matterhorn White base coat is on. Next come the navy blue and wine red stripes. It'll be done soon.
Thanks to a summer of R&R we'll have an airplane that runs great, works perfectly, and looks terrific. I hope we're not too exhausted to fly it.
