So I recently got back from my third aerobatic contest, the Northern California Aerobatic Challenge at Paso Robles. I finished in second place, a nice surprise considering some serious obstacles were encountered along the way.
After the Apple Valley contest (where I finished in sixth place), the plane developed a crack in the right fuel tank. Replacing this tank definitely falls into the “heavy maintenance” category, as it includes removing the wing from the aircraft, ripping open the top of the wing, replacing the tank, recovering the wing, doping and painting it, reattaching the wing and flight controls, and a thorough test flight.
The general consensus, based on previous wing tank replacements in this airplane, was that there was virtually no chance the plane would be done in time for Paso Robles. The lead time for even getting a new fuel tank was estimated to be several weeks.
There was some talk of flying a standard Decathlon or trying to work out a deal to use one of the northern California airplanes, but nothing ever came of it. Which was fine with me, becase after flying the Super D in the high density altitude at Apple Valley, I want more power, not less.
Paso Robles was pretty much written off in my mind until a week or so before the contest, when I heard that not only did we have a tank, but it had already been installed in the wing and the maintenance department was preparing to reattach it to the fuselage. Within a few days, the plane was back on line and ready to go.
As usual, I ferried the Super Decathlon to the contest. It’s always a nice change from instructional flying, because I don’t have to do anything but fly the plane and enjoy the view. Oh yeah, and navigate. The Super D has no navigational equipment of any kind on board, so I get to fly cross country using nothing but a compass and sectional chart. In an era of $300 GPS receivers, this kind of pilotage is something everyone learns in primary training but typically never uses again on non-local flights.
A persistent stratus layer along the coast made the navigation somewhat challenging. Many of the typical waypoints were under the clouds and I was left with a homogenous mountain range to find my way up to PRB. But find it I did.
So things were looking up on Thursday. The weather was great. The plane was in good shape. And I had a coveted early time slot reserved for practicing my sequence in the aerobatic box (every competitor gets 15 minutes of practice time the day before the contest starts). I took off around 10 a.m. and ran through the sequence once just to shake off the rust. I was pretty happy with how it went, and felt good during the climb back up to 5,000 MSL.
I came into the box a second time and pushed the nose over to gain speed, wagging the wings good and hard as you’re supposed to when starting a sequence. It was on the third wing wag that the stick froze — and I mean it locked up tight.
Initially I didn’t realize that it was only the ailerons that were immobilized. All I knew was that the airplane was 45-50 degrees nose down, approaching Vne, and some very important bits were not working properly. There had been no grinding, binding, clicking, or anything else in the control system. It was perfectly smooth and normal right up to the point where it froze.
They say time slows down when something like this happens. I wish. I’m sure there was a moment of denial on my part, but it didn’t last very long. I pulled the throttle to idle and was moving my hand down to the elevator trim slider when I realized that the stick would still move back and forth, just not laterally. It had stuck so firmly that I initially thought both elevator and aileron control had been lost.
The relief didn’t last long, becase it was about this time that I realized that the ailerons were deflected and the aircraft was rolling right at about 10-15 degrees per second, slow by aerobatic standards but more than enough to get my attention now. As I raised the nose, I instinctivly glanced at the outboard sections of the left and right wings, but there was no apparent abnormality with the control surfaces.
By this point the Super D had rolled about 40 degrees to the right. I started to use ever increasing force on the stick, hoping to overpower whatever obstruction was in the system, but it was to no avail. I used both hands. No good. Then I made a fist and whacked the stick from the side as hard as I could. Nada.
Time for plan B, the only alternative: full left rudder, which I had already started to feed in while working on the stick. Thankfully it stopped the roll. I added in some throttle to increase airflow over the tail, which improved rudder authority enough to overcome the deflected ailerons and return the airplane to a semblance of level flight.
So there I was, slipping through the sky without any idea of where I was headed. Lord only knows what the folks on the ground were thinking. I took a moment to catch my breath and then keyed the mike to let the starter (the contest equivalent of an air boss) know there was a problem.
Eventually the stick came free on its own after a couple of minutes of me just sort of slopping through the sky trying to figure out how I was going to land it like that. When I got it back on the ground, Bill and I pushed the plane into the hangar and spend the next eight hours taking it apart. Every cover came off, the seat came out, the carpets and floorboards were removed, the bellcrank tunnel came out, the stick boots were pulled, the wingroots were pulled off, the whole nine yards. We inspected the airplane below the floorboards (where the cables run) from the tailcone to the firewall with flashlights, mirrors, and more.
Eventually we found an unused 2″ pop rivet near the wing root aileron pulley. If you’ve never seen one, pop rivets have a long metal shaft that is used to drive them. We had one of the competitors who is also an A&P look at it and he was able to duplicate the jam using the pop rivet. My theory is that when I pushed over to go into the box, the negative Gs allowed the rivet to float up to the control cable, which was moving back and forth during the wing wags. Eventually it got stuck in the pully.
Anyway, we visually inspected every single inch and component of the aileron system and didn’t find anything else, so we test flew it again without incident. But that’s the first time I ever seriously considered bailing out of an airplane. I was totally calm about it, but the adrenaline really kicked in, so much so that later on when we were working on the airplane, I got really sleepy once it wore off.
Last year the airplane had a broken elevator cable during a flight. So now that the ailerons have had their moment in the sun, I’ll be expecting the unexpected from the rudder.
Just kidding. But it does prove once again that the first few flights after maintenance are one of the most dangerous times to be in an aircraft. The wing had been off the plane for the installation of the new fuel tank, and the mechanics did it pretty quickly. So that’s probably what happened — they just left an extra pop rivet in there. I rather like the composite planes that have the translucent inspection panels in the tail so you can look for this stuff before flying. Of course, in this case, that wouldn’t have helped since the object was in the wing root.
Throughout the next couple of days, I was regaled with stories of other aerobatic pilots who’ve been killed by FOD (foreign object damage). The guy who won first place related how his first aerobatic instructor got killed in a Yak 55 when some FOD got stuck in the elevator during a sequence.
So I’m not sure I won second place as much as it was God paying me back for all the hell He put me through.
With respect to the infamously confusing aerobatic box at Paso Robles, it didn’t confuse me, but it did get Bill. On his 2nd flight, he torqued out of the hammerhead and didn’t realize it until he was nose down, and then when he saw the box markers at an angle, he corrected the wrong way and zeroed that maneuver. He also did the final maneuver on the Y-axis, so that knocked him out of contention. He was probably tired after working his tail off to help find out what was wrong with the plane, so I think that played a part in it.
The key at PRB seems to be ignoring the runways. If you look beyond them, you’ll notice that the field section lines that radiate out across the valley are perfectly aligned with the box. But yes, it’s tough because the box is a square and it’s overlayed on a triangular runway.
Surprisingly, it wasn’t difficult to fly the airplane in the competition. I thought after the incident with the aileron jam that I might be reticent to fly the Super D really hard, but I just went out to have fun and ended up flying it harder than ever. It was great being down near sea level instead of up at 8000 foot density altitudes.
The flight home was interesting, too. On the way back the clouds obscured the southern half of the state, so I flew back in formation with the Pitts (he has a GPS) and we just circled down through a hole over Huntington Beach.
As always, when I got back many people asked how the contest went. I can sum it up by saying “I learned about flying from that.”