#15 Innocuous Break, Nearly Deadly Consequences
I was undergoing pilot training and was pretty new to the whole thing. I walked out to do my pre-flight checks before my solo flight. After doing my walk around, I checked the oil. Cessna 172’s have a dipstick that is attached to a cap that screws into the engine. You have to unscrew the cap and remove dipstick along with it to check the oil.
After I unscrewed the cap, there didn’t seem to be a dipstick attached to it. Long story short, the dipstick had broken off during the previous flight that had landed just minutes before. It had slid straight into the engine, where the crank-case had been chomping away metal from the tip. That metal was now circulating in the engine.
At that point, the aircraft was grounded because it was extremely dangerous to fly. At massive cost, it had to be stripped down, with the entire engine disassembled, and they actually had to find every bit of metal missing from the dipstick before the plane could be re-assembled and made flight worthy again. If in a moment of stupidity I’d taken off in that plane, I’d probably not be here today.
Credit: OfFiveNine