Second Thoughts

by w3woody

So now after a night of sleeping on it, I’m having second thoughts about the aircraft I looked at. Give that it is the first one that I physically took the time to look at I’m not sure if my second guessing is warranted–but I am having some second thoughts for the following reasons:

(1) The fuel gages are inaccurate. When containing a half-tank of fuel, the fuel readings show a quarter full. This was definitely on my list of things that I wanted to ask the seller to fix before I bought the airplane; it actually means the aircraft is not really airworthy: fuel gages is actually the first item on the GOOSE A CAT acronym. (Fuel Gages, Oil temperature, Oil Pressure, Seat Belts, Emergency Locator Transmitter, Air Speed Indicator, Compass, Altimeter, Tachometer.)

(2) The spring which helps return the flaps back to zero position is not able to move the flaps all the way back. When you set the flap control lever to the ground the flaps don’t move–until you nudge them by hand, at which point they pop back into position.

(3) The trim motor is unable to move the trim lever very well; sometimes it sticks and requires assistance to move.

Last night I didn’t really think of these things other than as squawks to be fixed prior to taking possession of the airplane; minor issues which just require adjustment or the replacement of an inexpensive part.

But today–I’m starting to think there is an underlying systemic problem.

See, an airplane operates as basically a series of pulleys and cables. Turn the yoke, and a bunch of pulleys and cables pull down the ailerons. Push the yoke forward, and pulleys and cables move the elevator surface. In an Piper Arrow, the lever that you use to put down the flaps pulls a cable that pulls down the flaps, and a spring returns them to the home position. Even in the fuel tank a float attached to a lever and a hinge which turns a potentiometer drives the fuel gauges.

And the one thing these squawks have in common is rust and contamination.

Rust on a pulley can cause the spring that returns the flaps to zero can cause the flaps to stick, and not return to zero. Rust on a pulley can make it harder for the electric trim motor to rotate a pulley. Even rust or contamination on the float lever arm hinge in the fuel tank can prevent the fuel gauges to read accurately.

And worse, because many of these cables pass through holes in the spar and other structural members inside the airplane, contamination or corrosion may be taking place inside those structural members rather than in the pulley itself.

So after seeing this I think the plan of attack has changed to me looking around at more airplanes.

Which is fine: my original schedule was sometime in the Spring.