One individual brought me his Cessna 140, and wanted an electrical upgrade. He had already dismantled the electrical system and removed the wiring, and couldn't remember how it went back together.
When asked what was wrong, I can't count the number of times that pilots have said something like, "It was making a funny sound." "It was doing something wierd." "It didn't seem right."
Recently a lightening strike that the pilot didn't report. Burns through the wings, propeller, radome, nacelles, and other places. His only squawks were minor interior trim issues; apparently the holes burned through the airplane (the pictures taken on scene with a digital camera clearly show daylight through the wing) didn't bother him too much.
Recently another pilot complained that his FMS kept tracking four miles off course in the heading mode, on autopilot.
One pilot squawked a voltage annunciator light on the airplane; he aborted a takeoff. I climbed into the airplane with him and noted that while applying takeoff power, both engines rolled back in RPM substantially while torque was increasing, then took off unevenly and very roughly. He wasn't interestedin the engine rollbacks; thought it was fine, but was very upset about the voltage.
One of my favorites occured one afternoon while I was kicked back in a small town terminal, doing nothing. A navajo reported in,and when he landed, I noticed that his left engine was feathered. He managed, after considerable effort, to turn around and taxi on to the ramp. The pilot climbed out, along with 13 people...like a clown car, except a piper navajo. The pilot approached, asking for maintenance assistance.
He indicated that he felt he'd had an oil leak, and had shut down his engine. He had just had two overhauled engines put on board, and the first flight was with paying passengers (the ones on board), when this occured. He had been at a canyon airport and drifted down to land at this rural field about the same time he ran out of range and altitude, luckily for him.
The engine had a hole in it. The mechanic who performed the work was notified. He wanted to know if we could tell the cause. Why, yes. The rod end had fallen off, and the rod had beat it's way through the engine case, and then the oil left through the hole in the case. Can you see the rod end, he wanted to know. Why, yes. It's down there. Why did it come off, he asked. It came off because apparently the end bolts fell out; they're lying at the bottom of the engine, visible wth the rod end, through the hole in the case. Why?
He reasoned that we ought to be able to put the cap back on, patch the hole, fill the engine with oil, and ferry it somewhere.
We hung up. Shortly thereafter, the mechanic left the country. The financial owners of the airplane called some time later, and asked me to go run the engine from time to time until they figured out what to do with the airplane. I obliged them. During the run, the brakes failed, the airplane lurched, and actually straightened out the S hooks on the tie down chains. The airplane got carted away a year later.
I recently reviewed a pilot training manual for a turboprop in which the pilot is directed to "lean the mixture above five thousand feet."
To say nothing of the things that get left in engines, left behind in safety critical areas, and fixed by pilots who think they're mechanics. One pilot told me he'd tightened the forward lower engine cowl attach bolts on a King Air, but that the nutplates must be stripped. He'd tightened them as much as he could, but they just kept slipping. I had to use a cheater baron a wrench just to remove two of them; my torque wrench didn't go high enough to measure their value. Apparently the tighter, the better.
Or another guy who used wire nuts to secure pieces of electrical cord from a household lamp, that was used to do the wiring behind his instrument panel.
Or the folks at a drop zone who asked me to do some work on their Cessna 180. Their pilot reported that the aileron trim was off just a little. It was out of annual, so rather than flying it, I began by checking the rigging agains the manufacturer maintenance manual. With the ailerons symmetrical, I noticed that the control yoke was turned half way left. I asked if this was normal in flight, and the pilot said no, normally it's turned all the way left, 90 degrees. I asked him how he made turns to the left. He didn't...make all turns to the right, and it's okay. Anything you can do to even it up a little, doc?
One pilot sqawked a gear unsafe light, but kept flying the airplane. On jacks, the gear was so loose in it's trunion that the trunion bracket and gear assembly moved independently from the wing; it was hanging on by several broken, and twisted undersized attach bolts. On another airplane the pilot(s) reported a popping noise each time they applied flaps in the pattern...but kept flying the airplane anyway. Turned out the spar was completely cracked through in three places. The popping noise was the spar grinding as it's position changed under an aerodynamic load.
We flew three avionics techs to a different C-130 once, to handle insurmountable avionics problems; terrible com. Turned out that a little re-education of the crew on how to use their volume control fixed everything.
I was in the process of doing work on a glider one night, and became tired. I placarded the glider as unairworthy, noted that none of the interior was attached or bolted in, set all the parts in the cockpit, secured the airplane, and flew home. I came back the next morning to find the sailplane gone. When the owner landed, back from giving some flight instruction, he saw me and chuckled. You're going to laugh when you see what I did. He had put everything back in place, setting it there unsecured, and went flying. The seat, and everything else in that cockpit was just sitting there, unattached. He thought that was funny.
Another pilot who espoused shutting off the mixture on student's while flying, called to report that he couldn't get the engine started. I flew to his location and found the mixture cable pulled out enough to interrupt fuel, and siezed in that position. Luckily it had happened on the ground, because had he done his trick in flight, he wouldn't have been able to restore power.
A write up for a fuel leak. Three to five gallons a minute. I found the person who made the writeup, and enquired as to how they knew that was the rate of leakage. "Because we put a bucket underneath it and it filled up in a minute."
Fair enough. But they couldn't duplicate it, and decided to go flying anyway. I put an end to that, and grounded the airplane. It took three hours of trying to duplicate it, but I did get it to leak, and it did leak a LOT. I found that the fuel feed line to the pressure carburetor had been fabricated using aeroquip hose and automotive air conditioning fittings...which didn't fit. I refabricated all the aircraft fuel lines properly and installed them myself. No more leaks.
And on it goes. I just love writeups like "radio doesn't work." Or
"Engine sounds funny." These tell me absolutely nothing, and make the person executing the writeup look like an idiot.
I really like the folks who never write anything up. "That thing is supposed to be missing fastners...they make them 150% stronger than necessary...you can afford to lose a few. Let's just bend it back, good as new. Gotta love it.