Lesson 120
21 August 1999
1.1 hours
Tailwheel Lesson 5

I drove to the airport, met Carmine, trotted over to the Citabria's hangar and shoved it out.  Preflighted.  Noticed that both fuel gauges showed 1/4 fullk, but because there was no stick or anything to plumb the tanks I just made a mental note to mention it to Carmine.  Kicked all three tires and looked at the tailwheel assembly for a while to see how it worked (this will be seem more relevant later) until Carmine arrived.  I mentioned to him that the gauges indicated quarter tanks.  He said he likes to fly in the pattern with the tanks not full--no need to haul all that fuel up and down when you don't need it.

"Well," I said," if we run out of gas at least we'll be close enough to land on the field.  He grabbed a wing and wiggled it.

"There," he said. "You can hear it sloshing around."  Then he flipped on the master switch and called for fuel.

With the tanks full, we got in, fired up the engine, and taxied to runway 5.  As we neared the hold line I asked Carmine how you can tell when the tailwheel breaks loose in a tight turn.  He said you can feel it, grabbed the controls, and did a 360 on the taxiway to see how it felt to him.

He said, "You can feel it."

I was curious to try it myself, but instead took his word for it, ran the engine up, and took off for some touch-and-goes.  The wind was about 7 knots and pretty much down the runway, but we soon found that there was a crosswind aloft, varying between about 30 and 60 degrees across the runway.  It was more or less that way on final and on the approach half of the runway, but switched to mostly headwind over the upwind end of the runway.  I did a bunch of landings, none of them very good, but no real disasters.  The main thing was, I just didn't seem to have the feel of slipping in that variable crosswind today.  It should have been easy, because the wind was light and there were no real gusts, but it just didn't seem to be a terrific day for me today.  (That's probably what I get for helping my son Chris move furniture late last night.)  After about an hour of flying around it was time to quit, but we were both enjoying the day, so I decided to go around one more time.

Now, on the last three touch-and-goes, the tailwheel had started shimmying, and Carmine told me shove the stick forward to unload the wheel until it stopped.  The second time that didn't work, so he had me stop dead.  The third time the same thing happened.

Then came the final landing.  We agreed that it would be to a full stop.  I got lined up, hit the right speed, and got it down nicely--my best landing of the day, even though the tailwheel started shimmying again.  We slowed right down to maybe 30 or 40 mph, and I began to turn off on the first taxiway.  It's only a 30 degree turn, but Carmine felt that we were going too fast to turn and without saying anything, jammed in all the left rudder he could.  (He said later that he didn't see any sense in wearing out the brakes and having to taxi slowly past the ramp when we could just whiz on down the runway to the second taxiway.)  All of a sudden I saw that we were swinging around sharply to the left and stomped as hard as I could on the right rudder--Carmine probably did, too--but it didn't have any effect and there we were, in an increasingly tight left turn.  At that point I realized that Carmine had the airplane and let him fool with it.  We did most of a 360 on the runway--fairly gracefully, I thought, but the thing was definitely out of our control--and came to a stop.  When we started taxiing again, the tailwheel was really shimmying and bumping, and Carmine said he thought the tire was blown.

I should mention that each of us had said several other things both before and after that pretty little 360 on the runway, but "The tailwheel's blown" was the first of them that the FCC would sanction on the radio.

We taxied slowly to the FBO hangar and got out.  And sure enough, the tailwheel tire had blown.  The cords were showing almost a quarter of the way around the outside of the tire, and the blowout was about six inches long, right along the center of the tread.

But "tread" isn't quite the right word.  I had seen during the preflight that the tire was bald.  But it had been bald all along, and although I had seen it, I hadn't noticed--hadn't thought about it.  On the other hand, I hadn't noticed the tread showing anywhere, and I'm pretty sure I would have noticed if it had been.

Carmine said that was the closest he'd ever come to groundlooping.  (It was for me, too, of course.)  His face had an odd pale-and-flushed look to it.  I wondered if mine did, too.

I said I thought that that tire must have been blown on the previous three landings, when the wheel began shimmying, but he said it hadn't, that we would have known for sure if it had been.  He located a new tailwheel assembly with a brand new tire--with tread grooves over half an inch deep--so it was easy to see what I hadn't noticed during the preflight: that the tire was worn out.

After mulling it over during the drive home, I came to the conclusion that the tire surely must have been losing air by then, even if it wasn't completely flat.  It had never shimmied before, even when I made much worse landings than today, so something was different today.

Anyway, now I know--almost!--what a groundloop feels like.  What fun!

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