“Airplane on ground” That’s the notation someone uses when ordering parts or maintenance services for an aircraft that’s stuck someplace it doesn’t want to be due to mechanical issues.
When airplanes break it’s due to one of many factors. Could be that the highly qualified and professional aircraft mechanics (grease monkeys) missed something on the last inspection or put something on or back together incorrectly. (Why do we have parts left over?) This is not usually the case but it happens. I know of a drop zone’s Cessna 182 that had 3! engines stop in mid flight in less than 2 years! Each time the mechanic came out and found that the fuel filter was full of some kind of rubbery orange gunk. No one could figure out what the stuff in the filter was so they would just clean the filter and go back to flying. After the third dead stick landing the pilot took the plane to another mechanic who discovered that the regular mechanic had left an orange rubber mallet inside the fuel tank and it was slowly dissolving.
And of course sometimes when the mechanics give the pilot a well maintained aircraft in perfect (sort of) condition the ham fisted throttle jockey (pilot) brings it back in less than perfect condition. “Honestly, I was just flying along straight and level when the windshield cracked! Out of the blue! I wasn’t teaching myself aerobatics and lost control going over red line and almost killing myself, I swear!” (not me but one of my jump pilots)
But most of the time it’s just that some essential part has decided that it’s had enough. Just off the top of my head my in flight breakdowns are:
2 twin engine aircraft that both lost the vacuum pumps on both engines, within minutes of each other. Losing your vacuum pump means losing most of the instruments that are necessary for flight in IFR conditions. (clouds) Of course in both cases I was in IFR conditions, so yes things got exciting.
1 piston coming apart shortly after takeoff with a full load of skydivers. Dead stick landing into a short dirt strip with the jumpers onboard because they didn’t panic fast enough. (waited to see if the really bad sound from the engine ment they weren’t getting any more altitude.) Here’s a hint from an old pilot. If the plane you’re riding in suddenly makes a big bang sound and starts shaking violently, AND YOUR WEARING A PARACHUTE. It might be time to leave and go get help.
2 cylinders with holes in them on twins. (Thank God) One started burning the cowling, shut the engine down and landed on one. The other started blowing oil all over the place. Oil pressure went down below red line, oil temperature went above red line. Shut it down, landed on one. BTW it was at night, in IFR conditions, over the desert, with both vacuum pumps out. (see above)
2 alternators that stopped alternating. First one was over Africa, at night. Had to fly for 8 hours by flashlight over the Sahara. (long story. I’ll tell it sometime.) Second one was over Minnesota. Also at night but the story isn’t quite as riveting.
1 flap malfunction on my first long cross country as a solo student. Went to put the flaps down and they just went up and down, up and down, wouldn’t stop moving. First no flap landing ever. My instructor hadn’t gotten around to teaching me that yet.
Transponder altitude encoder inop = Claim ignorance and bluff my way from Egypt to Minnesota. It wasn’t as much fun as it sounds.
Big chunk of a 182 spinner flying off due to icing. Had to reduce speed due to vibration and continue across the Med to Rome.
Valve cover gasket blown. leaking a lot of oil. Happened in Greenland and a new one was going to take 8 days to ship. Made one out of gasket material I found and took off for Iceland the next day.
3 times I’ve had a landing gear light not come on confirming one of the wheels is down and locked. Scary landings but no gear collapse.
That’s all the scary things I can think of for now but it’s actually not all that bad considering I’ve been flying for 38 years. Heading to Florida in the Great White Hope today so fingers crossed!