Technicalities: It Will Maybe Be OK

Chasing down a starter issue results in a surprise conclusion. Peter Garrison

Many voices crowded the advisory frequency as I approached Paso Robles, but by the time I was on the 45 the other pilots had landed and silence reigned. I landed long on 19, turned off at the end, and found a parking spot at the end of a long line of visitors to the annual Antique Aero invitational barbecue.

Three hours later it was time to leave; I was due at another barbecue back in Los Angeles. That's California in summertime — just one barbecue after another.

A couple of guys helped me push my homebuilt out of the sloping rough and up onto the taxiway. A Lockheed Lodestar, sleek behemoth, was starting its engines farther down the taxiway, but I would soon be out of its way.

I pressed the starter button. There was a sort of pop, and then nothing. I pressed it several times. Still nothing. The voltmeter read 8 volts — not a good sign in a 28-volt airplane.

I pushed Melmoth 2 back into the weeds and watched disconsolately as the Lodestar lumbered past.

Had the starter solenoid failed? But that would not account for the low voltage. What had made that odd sound? It must have been a major electrical short. I took off the side panel of the cowling, expecting to find something blackened around the batteries. No, all looked normal. The prop turned freely. Apparently, the battery — actually two 12-volt motorcycle batteries wired in series — had failed suddenly and catastrophically.

Half an hour later Antique Aero's start cart got the engine running. As I taxied to the approach end of the runway the voltage kept dropping, however, and so I turned around and taxied back. I must have had the rpm a bit higher now — alternator output is very sensitive to rpm at the low end — because the voltage started coming back up, and by the time I was back where I had started it was at 28 volts. Well, I thought, it'll probably be OK; the alternator would support the radios, gear and flaps, and I would get home without any problem. And so I turned around and taxied out again.

At the approach end I started to put the flaps down but then reflected that I might as well put as little load on the system as possible. I left them extended a few inches — they are Fowlers and normally translate aft 10 inches or so for takeoff. Once airborne, I retracted the gear. Good — up and locked. I then raised the flap handle. Nothing. They didn't budge.

Now, this was puzzling for a couple of reasons. For one, the hydraulic system had just retracted the landing gear, which takes a great deal more power than retracting the flaps does; in fact, the flaps would practically retract themselves if they were not connected to hydraulic cylinders. So why would they not move? The voltage was still 28, so there was alternator output; on the other hand the ammeter, which displays charging current, stuck at a solid zero.

I climbed to 9,500 feet, where the penalty for having several inches of flap sticking out turned out to be just a few knots.

Since the flaps had recused themselves, I suspected that the landing gear might be uncooperative as well. I should have taken the precaution of lowering it at a high altitude, but for some reason I waited until I was at 3,000 feet and a few miles from my destination.

The three legs of my gear are mechanically linked and do everything in unison. Hydraulic power releases the central up lock; the gear then drops most of the way on its own accord, but, because of the aerodynamic drag on the forward-swinging nosewheel, a little extra force is needed to get all three wheels fully down and locked. A gas spring is supposed to help the nosewheel along, but it evidently wasn't doing it now: The gear had dropped, but it had not locked.

Strangely enough, I had foreseen this eventuality. For the past 12 years I have always carried around in an inconspicuous corner of the cabin an aluminum tube about 5 feet long. There is a small hole in the back of the nosewheel well that provides a visual check of gear extension; the window, a piece of acrylic plastic, is held in place with aluminum tape. I peeled it away, stuck the pole through the hole, felt about until the tip of the pole found the nosewheel strut, and pushed. On the first try, it swung forward and locked.

The rest of the landing was uneventful, except that I turned off the runway one taxiway farther down than usual. I got to the second barbecue a little late, but no matter; it was not as good as the first one anyway.

I could not figure out what had happened. Why would the gear go up, which required a lot of power, and not come down, which required very little? And why, by the same token, would the flaps not retract, when I supposedly had 30 amps available from the alternator? Were the batteries somehow sucking up power, and if so, how? Where was it going? And what had gone wrong with the batteries, anyway?

A few days later I installed new batteries and charged them. I found one of the old ones very low on fluid, but whether that was a cause or an effect of the failure I could not tell. I then attempted to retract the flaps. The hydraulic motor replied with an uncharacteristic whine, and the flaps did not move.

I checked the hydraulic fluid level. The reservoir was empty.

I looked under the wings and fuselage. No sign of a leak.

I took out the back seats and the floor under them. I already knew what I would find, and there it was: a huge pool of red stuff, and not Château Lafite.

The hydraulic line to the retraction side of the right inboard flap actuator had popped out of its nylon fitting. Any attempt to raise the flap just sent the ruby oil squirting out into the space under the seats.

So this, as far as I can tell, is what happened. When I retracted the flaps after landing at Paso, the brief pressure spike caused by the flap hitting the up stop caused the connector, which must have been working its way toward freedom for a long time, to finally come loose. The battery failure was a separate event, sheer coincidence. Later, when I started to lower the flap, the fluid that should have been returning to the reservoir instead ran out the open line. After I took off, there was still enough fluid left in the reservoir and lines to retract the gear. When I tried to retract the flap, however, it didn't move because there was no pressure; fluid was just pouring out the open line. There must still have been enough fluid left in the reservoir and the landing gear lines to get the gear past the up locks, but not enough for the full down cycle.

So there had been two unrelated but practically simultaneous failures, one electrical, one hydraulic. Each was improbable. I've had the flaps working for six years without a fitting failure, and I've never before had a battery say "pop" and suddenly go dead. Yet the two events had occurred so close together in time that they appeared to be the same.

One of the problems of having the only plane of its kind is that everything that happens to the type happens to you. While I was designing and building my airplane, and since then, I have fallen asleep many a night thinking about what could go wrong and how to prevent or remedy it. But those wretched gremlins whose job it is to dream up weird new glitches — they must never sleep at all.

Peter Garrison taught himself to use a slide rule and tin snips, built an airplane in his backyard, and flew it to Japan. He began contributing to FLYING in 1968, and he continues to share his columns, "Technicalities" and "Aftermath," with FLYING readers.

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