Just heard about this recent story of a pilot who made three (count 'em) emergency landings in one day to due smoke in the cockpit. After the first landing, it seems the pilot discovered an exhaust hose clamp or the hose itself was to blame. The pilot reportedly tried to fix the aircraft himself, at one point using parts from a local Wal-Mart. Each time he took off, smoke filled the passenger compartment. After his last landing, his passenger jumped out and was injured. The plane caught fire and was substantially damaged. One wonders if the pilot was still convinced he could fix the problem himself. In addition to his questionable aeronautical decision-making, the pilot did not hold an A&P certificate. Oh, and it was his passenger's first ride in a small aircraft.
I'm not sure if this is still the case, but when I was a high school student, girls had to take home economics and boys had to take shop class. Girls presumably learned how to cook and sew and boys learned how to use tools and curse. Talk about social engineering!
A cartoon I saw in shop class stuck with me, probably because I like puns and the play on words. The cartoon showed two mechanics trying to loosen a pipe fitting with a large wrench. If you know much of anything about pipes and wrenches, you quickly realized that these guys were having difficulties because they'd slipped a length of pipe over the handle of the wrench to provide more leverage.
Of course they were drawn in such a way as to reveal they were straining mightily - faces swollen, sweat spilling off their arms. In the right edge of the frame was another mechanic, wiping off his hands as we walked toward them. He's the only one speaking and his words were "Did somebody say all it would take was one more jerk?"
My shop teacher used this an as example of how to disrespect tools, use them incorrectly, and create a dangerous situation in the process. He was trying to teach us to think rather than use brute force. He warned us to avoid becoming what is sometimes called a hammer mechanic (someone who bangs on things to fix them) or a pliers mechanic (someone who uses tools inappropriately and ends up damaging the very thing they are trying to repair).
I've been thinking about that shop class because lately I've been seeing a lot of aircraft maintenance problems. In fact, I've had too many flights cancelled recently because a plane was broken and my income has suffered mightily. Some of the maintenance problems resulted because a part just wore out from use. Some of the problems were because the aircraft had been repaired, but the logbook entries were not taken care of properly or because the incorrect parts were used. Some aircraft were damaged because the pilot operated the plane is such a way as to cause the damage.
My observation is that pilots and aircraft owner/operators tend to be far too optimistic when it comes to mechanical things. I can understand the owner/operator being in denial because they want to make money or (more realistically) minimize their losses. I think pilots tend to be optimistic for one simple reason - we want to go flying, dammit! Pilots are the ones most at risk for being overly optimistic, especially when you stop to think that their wallet, their pilot certificate, and or their life could hang in the balance. It's an old saw, but I'll repeat it: A good pilot is a pessimist.
Notwithstanding this story about goats being sacrificed to fix an electrical problem with a Nepalese 757, seldom is there much mystery about what is broken on a plane. This brings up an important point for all concerned to remember: Things wear out. Anything made by the hand of humans has a useful life and we need to make peace with that fact. More often than not, there is some warning that a part or device on an aircraft is failing or on its last legs, so the first weak link in the maintenance chain is the pilot who doesn't report the problem after their flight or who takes flight in spite of a significant discrepancy. Some examples include:
Heading indicators that begin spinning after just a couple of steep turns.
Attitude indicators that become lazy and don't agree with the pilot's view of the outside world.
ATC regularly complaining that a transponder's mode C altitude reporting is intermittent.
Avionics frequency displays that don't function in dim light.
Engine starters that only engage after the fifth attempt.
Tires with no tread left or with flat spots.
Loose alternator belts.
Multiple, missing cowling screws.
Landing gear struts that appear partially collapsed or are leaking fluid.
Out-of-date GPS databases.
There's really not a lot of mystery to aircraft maintenance, aside from where the money will come from to pay for it. Pilots need to be careful with planes they fly and operate them skillfully, carefully and conservatively. And above all, a good pilot is a pessimist.