Here’s our Cheyenne at Aircraft Engineering
in Bartow, Florida, split at the “C” flange
while the hot section is performed.
Have you ever noticed how old married couples sometimes start to look like each other? Or that ardent dog lovers possess a startling resemblance to their bassett hounds? Crazy as it sounds, I fear that I am beginning to look like my airplane.
The 1980 Cheyenne I that my wife, Cathy, and I own is not necessarily a bad doppelgänger to have at my age, but the parallels are beginning to take on a certain eerie quality. Though I am more than twice as old as the 32-year-old turboprop, we’re at about the same spot in our respective life expectancies. If we use the rule of “dog years,” I’d say the airplane and I are at identical points in the trajectory of our lives. In a sense, we’re both old and not worth much, but still running well and somewhat oblivious to the actuarial facts of life.
We both require a certain amount of maintenance. For me, the issues have revolved around an old eye injury (a risk for glaucoma), another ophthalmologic thing called “vitreous detachment” (sounds vaguely risqué to me) and more frequent visits to the gym. For the airplane this year, it has boiled down to a “hot section.”
A hot section involves inspection and replacement or repair of the bits that are exposed to the highest temperatures in the PT6 engines that adorn the Cheyenne. The compressor turbine disc, compressor turbine blades (pricey as we will see), shroud housing and combustion liner, among other parts, comprise the hot section inspection.
There was great discussion with Bill Turley and Mike Naab of Aircraft Engineering in Bartow, Florida, about “what to do with the engines.” Since ours are closing in on TBO, we had some serious decisions to make. As our hull value has decreased in this down market, engine overhauls have become problematic. How can I possibly explain to Cathy that we need to invest at least $150,000 per engine when the airplane itself isn’t worth that kind of money? Then there are the horror stories of engines taken apart for overhaul and “additional items are identified,” making the cost even higher. With the parts scattered on the shop floor, it is hard to turn back, much like when the plumber has taken apart the toilet and tells you the price has just gone up.
We all agreed, however, that a hot section inspection was a reasonable intermediate thing to do on the left engine. The right engine had enjoyed a hot section a few years ago. It was during this time that I learned about the expensive little things inside those engines. Bill joked that I should make a necklace out of the turbine blades, as they were as valuable as diamonds.
Bill Ahern at Southeast Turbines came to Bartow, where the left engine was “split” at the “C” flange. A special hoist held the front part of the engine and the propeller in midair while the hot section was inspected. Soon came the word: The guide vanes had burned through (see photo), and that fact mandated all new turbine blades. These little babies roll out of the factory at $265 apiece. Good thing there are only 58 of them.
