“What’s that noise?” asked Gus.
“What noise?” I replied.
“Listen.”
We were at 1000 feet, over the lake, headed home after a short but glorious flight in the Pulsar on a spring day.
I strained to hear any extraneous sounds. The purr of the engine was normal, the rush of air through the vents was normal, and there were no squeaks or rattles…
Until there was.
A squeak. An odd squeak.
“It’s coming from the back. Did you put anything back there?”
“No, I didn’t even look back there.”
Soon we were on the ground. I tried to hear the noise again with no luck. We taxied up to the hangar and shut down. Then a high-pitched meow.
“Oh, my gosh!” I pushed the canopy forward. “Ace got into the airplane.”
A frazzled cat emerged from the cargo area and jumped into my arms.
“I guess we’ll need to add this to the preflight.”
When you’ve finished your preflight, you’re only half done. When you fire up the engine, continue your concentration on the health of the airplane by listening carefully to the engine. After you have done this many times, you’ll develop a sixth sense for happy operation, making problem noises stick out for attention.
As you get underway, keep listening. On run-up, on takeoff, and on climb-out, keep your attention on sounds. If you’ve never done this before, you’ll be amazed at all the things you hear.
Keep listening throughout the flight. From engine noise, air noise, whistles, vibration, and frequency changes, you’ll fine-tune your trouble antenna. When you land, pay attention to brakes and tires and anything else that comes to your attention.
While squeaking cats are typically not a problem, other sounds can be. I’ve herded up my top five for attention.
Engine: whistling or hissing sound; frequency changes; erratic idle. You may be hearing an induction air leak. Your aircraft engine needs a precise balance of fuel and air plus compression and a well-timed spark to produce efficient combustion. Any problem with this mix will affect performance. Induction air leaks will do the least amount of damage if caught and fixed promptly. Check gaskets, hoses, flex elbows, clamps, head to intake tube joints, and even alternate air doors not closing all the way.
Engine: clicking, missing, and rough-running sounds when cold that go away when warm. The most serious is sticking valves and especially an exhaust valve stuck closed. The cause can be a buildup of deposits and/or corrosion. Don’t be fooled if the noises go away upon warmup. Sticking valves may free up temporarily but don’t get better over time, so this is something to get checked out.
Banging. This is the sound of something coming loose, something that came loose, or something about to come loose. Most often this is baggage shifting, parts coming off, or the dreaded “Where are the wheel chocks?” Double-check baggage security before leaving. Use your hands to feel anything that looks loose, and don’t take off if there are mystery noises.
Radio noise. Murphy’s Law states that any radio noise you hear will be on your end, not the other end. The first thing to check is your ground wire. Is there damage? Are connections tight? Do you have multiple grounds? If so, change the signal path so you have just one path to ground.
Thumping noises while taxiing. Probably tires; check this out instead of dealing with it later, since a tire defect can send you into the weeds upon landing.
You’re on your way to becoming the airplane whisperer.
