OK, forget everything I said last week. If the damned engine ever gets back on the plane, we’re not going to follow our original break-in plan. I’m going to do it by myself. Or at least the first part of it.
Now, in case you’ve forgotten, back in early September the freshly rebuilt engine was bolted onto Tess and I innocently planned a break-in flight. My flight plan had us taking off from Santa Fe early in the morning, turning south and shooting down the gap between the northern tips of the Sandias and Rowe Mesa at low altitude, turning east at Moriarty, then barnstorming at 500 feet AGL across the empty wastes of eastern New Mexico and over our home base of Santa Rosa—where the colors on the sectional chart change from khaki to pale yellow, telling us we’d be below 5,000 feet. On we’d fly into West Texas, our nose pointed toward Herford, a town southwest of Amarillo, where we’d stop for fuel. All of this was planned for an optimal break-in: The lowest possible altitude; minimal low RPM ops; no long descents; landing with some power; and keeping the taxi as short as possible.
Next, we’d fly to Palo Duro Canyon to follow the wide dry wash called Prairie Dog Town Fork. This is where the sectional map changes from pale yellow to tan. We’d then be below 3,000 feet for the first time on the flight. A scant thirty miles farther on, at a random lat-long, the color on the sectional map changes to sage green and the terrain below our wings would stand at 2,000 feet above sea level. We would have travelled 349 miles to reach this point. There’s no closer low-lying land. From there we’d turn northeast and follow the edge of the escarpment until we reached Weatherford, OK, elevation 1,605 feet.
The next morning we’d do it all again. In reverse. Then it would be time for the new engine’s first oil change.
Of course, as you all know, that flight never got beyond Santa Fe’s Class D airspace. The engine vomited out all its oil in minutes. As it was really part of the racing story, I wrote about it for GA News, and was roundly criticized by my readers for having a “passenger” along during a “test flight.”
First off, it wasn’t a test flight. It was a break-in. Secondly, Lisa is a pilot, and a common (if not required) crewmember, so I never think of her as a passenger. That said, I do know the statistics on engine failures after rebuilds, and she and I discussed the issue at great length. She accepted the risk and basically threatened to chain herself to the propeller if I refused to take her along. But then she also insisted that we create a series of customized engine failure checklists for each runway we might use, and procedures at each altitude—a degree of safety I probably wouldn’t have bothered with on my own.
Still, I never thought of it as a test flight. Only an engine break-in.
But the story doesn’t end there. Remember last week when I told you that the flight instructor I use for my flight reviews declined to help me with my current currency issue? He followed that up with an email that quoted 14 CFR Part 91.407, a Federal Aviation Administration regulation titled, “Operation after maintenance, preventive maintenance, rebuilding, or alteration.”
I won’t bore you with the details, but the crux of it is that it’s verboten to carry a passenger in a plane after any maintenance that “may have appreciably changed its flight characteristics,” until the airplane has undergone an operational check, and that flight is logged in the airplane’s records. The Feds don’t use the word “test flight,” and any pilot with a Private ticket or higher can undertake the operational check. The section also includes several exceptions, including one that says a ground check will suffice if the rebuild “has not appreciably changed the flight characteristics or substantially affected the flight operation of the aircraft.”
Soooooo….. Does a simple engine rebuild fall under this regulation? As it turns out, that’s a hotly debated subject, but one that I’ve been thinking a lot about since the reg was pointed out to me. On the surface, I’d say, no, it doesn’t. At least not for most rebuilds. If you follow the manufacturer’s recommended schedule for overhauling the engine, you’d be hard pressed to tell the difference in performance before and after a rebuild—except when looking at the balance in your checking account. And it certainly wouldn’t cause an “appreciable” change in flight characteristics. Even if you put off the overhaul until your engine was getting pretty doggy, you might find your plane had quite the spring back in its step, but it wouldn’t fly differently. I personally feel that the intent of the law is aimed more at things like the installation of vortex generators, which totally change takeoff performance.
On the other hand, we didn’t just rebuild our C-85 engine. We (legally) converted it to a 0-200 stroker. That’s mainly for ease of parts availability, and while the Supplemental Type Certificate (STC) paperwork says there’s no power change, most people I talked to reported a lovely increase in horsepower. Was that because they put off the rebuilds so long that it just seemed better compared to their worn out engines, or does the stroker really deliver more oomph?
The more I thought about it, the more I began to wonder if my “new” engine fell under 91.407, but the coffin on my original plan wasn’t nailed tightly shut just yet.
But the next nail came swiftly. Now, I’ve been behind on my reading. I have no excuse for that because it’s not like I’m busy flying, or anything. But two nights ago, I finally got to the August issue of AOPA Pilot. As I was thumbing though it, I came across Mike Busch’s excellent Savvy Maintenance column. And guess what? Yeah. He was talking about the damn 91.407, and it sounded like he was talking directly to me.
He was quick to point out that the regulation isn’t clear about what types of maintenance require a “test flight,” but he specifically talked about a crash following an engine overhaul. Well, a crash plus a second almost crash, both of which, thankfully, had happy endings—at least for the people in the planes, if not for the planes themselves.
In the first crash the pilot had his girlfriend and her two young children aboard on an Island-hopping day adventure in Puget Sound, Washington. Busch caustically wrote, “I can’t help asking what possessed this pilot to conduct his initial post-maintenance test flight (immediately following an extensive engine teardown and propeller overhaul) on an overwater flight with a cabin full of passengers, including young children.”
Well, at least I had the sense not to take my son with me on the first flight, but maybe I wasn’t taking this seriously enough, even so. I gave the article to Lisa.
She’d previously read the readers’ comments and the CFI’s email. The next day she told me she’d read the article and that she decided that when we get the engine back, I should orbit the Santa Fe airport—solo—for an hour or so, land, inspect, then fly solo back to our home base. If all was well, on another day we could make the formal break-in flight to sage green on the sectional chart as a team.
She reflected for a moment, then added, “the Universe usually needs to tell me something two or three times, but eventually I listen.”
Yeah. Me too.