Thursday, October 01, 2009

Not Everything Breaks at the Worst Possible Moment

After shutting down the engines I still have lots more switches to turn off, paperwork to do, and some tidying to do in the cockpit. I see the engineer and the PRM looking at the left engine nacelle. But it's the right one that has the leak. I open the window and they say the same thing, "I thought you said it was the right one that was leaking."

"It is," I tell them. "I left with it clean, so what you see is just from the one flight. Also the left tach is dead.

"The left one? I though it was the right one that had the problem."

"It was. But the right one is still going strong."

Apparently the left engine was feeling left out with all that concern about the right one, and wants some attention, too. I have a moment of irrational worry that a broken left tach cable somehow left a trail of havoc inside the engine, but I know it's inside a channel, separated from everything else. And apparently from itself now.

While I gather my belongings inside the airplane, they hook the airplane up to a 1950s vintage Ford tractor and haul it into the hangar. The engineer and a couple of apprentices swarm over it and start pulling it apart. The right oil leak was exactly what they had field diagnosed it to be, something to do with an O-ring, but clearly not as disastrous as what happened to Challenger. I'm glad I don't fly this thing in outer space. I don't remember if they told me what the new leak was, but I had three different people come up and ask me, "Did you have propeller control during the flight?"

Now that's a pretty bizarre question, along the lines of "were you able to shift gears during your trip?" to the driver of a car. I told each one yes, and assured them that, had I lost control of propeller RPM at any point during the flight, it would have been one of the first things I reported after landing. It turns out that during their routine check of all engine controls from the cockpit, the right propeller lever does not control the propeller. They later showed me a broken end of the cable. I told them about the momentary difficulty I had in the run-up, but that the RPM came back normally for cruise. It's possible that the cable broke at that power adjustment, because when I sync props it is my habit to move only the left one until the beats match. The propellers both went full fine for landing, but apparently the broken cable ends would have pushed together and worked the mechanism. More likely the cable broke at the moment they tested it in the hangar. Sometimes things break at the right time.

I give them my big list of everything this airplane has complained about lately, and drag my luggage out of the shop into the lobby, where there turns out to be doughnuts. Life is now good.


Wayne Conrad said...

I hope you don't ever stop writing about these things--the maintenance puzzles, the gas issues, the customers that need equipment with this much power and just that temperature. Yours is, after all, a career of making a machine do things. The machine's quirks and your reaction to them are part of what makes your life in the air (and hanger) interesting.

Jimmy said...

Always nice when it works out like that...I hope it continues that way for you.

I've had pretty good luck this year. I had a magneto drop problem clear itself magically after a good hot run-up in YXY, only to re-appear once we got back to base a few days later. Similarly the upper bearing block went on the nose gear when I started braking on arrival at home after a week on the road. The gear issue would have really sucked to deal with on the road. Last time it happened I had to do over a dozen gear swings with the emergency handle. My arm ached for a week...

Now that I've committed that to writing I'm going to get stranded somewhere lol.

Anoynmous said...

The propeller pitch cable broke on the family Aztec just before a planned flight to Mexico. Much better than having it occur during the trip, for sure.

And it happened within quick driving distance of the Piper factory, so getting the proper part for repair was no problem.

zb said...

"... they hook the airplane up to a 1950s vintage Ford tractor and haul it into the hangar." Beautiful! Sounds just like fixing (or even developing!) a new, high-tech piece of electronics with ancient lab equipment.