Back in July I had an alternator failure while taking off. It wasn't that big of a deal, we were only 10-15 minutes from home base - we just shut off pretty much everything but the radios. We let tower know about the failure, and they cleared us right in. It was a good experience for having only about 10 hours at the time.
Today while doing aerobatics, the engine quit. After about 5 tries it came back on. It stopped while entering a spin, and it usually doesn't happen when the RPM was up as high as we had it, but today it decided to.
After practicing engine-out procedures in the practice area, my instructor and I decided to go home and practice some in the pattern. My instructor was about to intentioanly "kill" the engine, when it did so itself. I thought it was some good acting, but after landing we had to get out and push the plane off the runway.
I had a leading edge flap fail to retract indication and we had to burn off some gas and go back and land....turned out to be a faulty indication. Also had a generator failure when I was a S/O. So nothing too exciting.
Once in a 150 the carb heat cable failed in a way that the carb heat was on all the time. I just lost 100 rpm and the engine sounded funny so I headed for the nearest airport. It took 10 minutes to get there but then I figured it was not getting any worse so I pressed on another 20 minutes to my takeoff airport. The next day we found out what the problem was.
The worst and most unsafe experiences were with bad weather or low fuel in small planes...only the failure of the pilots brain....not the airplane.
Both my failures were on C-152's.
The first, during my private, the transmitter on our comm radio died just before entering our class D airport. We decided to divert to an uncontrolled field, land and call the tower on a cell phone to let them know our intentions. The funny part was that they made us squak 7600 but the transponder decided to report 7700 instead. The tower switched us back to 1200 immediately.
The second was a vacuum failure just about 10 nm from our base airport. We were VMC so it was not a big deal, the good learning experience I've got was to actually see what happens to the instruments. The first thing I noticed was the DG card spinning rather fast, there was no immediate indication of a failure on the AI during level flight, the vacuum indicator needle was all the way down.
I was on an IFR training flight with my instructor in IMC and we lost comms. Both radios out, nothing but static. We manage to get approach back just long enough to get cleared for the ILS back in, and then lost the comms again. Then after the GS intecept, I start getting the LOC needle swinging back and forth. So I'm scanning both NAVs at this point, and I break out of the clouds at about 100 feet above DH. After that day my instructor and I swore we would never do a training flight in our school's 172Ns again. I was dripping with sweat by the time we hit the ground, and I think that is probably the most scared I have been so far. At least he let me lose the foggles for a while....