"Tony" wrote in message
oups.com...
[...]
What about those of you with 500 plus hours: what has your experience
been like? Am I just unlucky, or typical?

Probably similar. Like Robert, I wonder why you felt it necessary to make a
precautionary landing when your vacuum pump failed in VMC. Were you flying
under IFR? I was VFR the one vacuum pump failure I experienced, and I not
only completed that flight, but made another one to take the airplane to the
shop to have it repaired ("placarded" inop).

As far as other mechanical problems/precautionary landings go...

I did have a magneto failure. I didn't find out until my next flight. The
only symptom was slightly higher fuel flow for the same power setting. So,
no precautionary landing there, but there would have been had I any idea
what was actually going on.

My most dramatic (as in nerve-wracking) precautionary landing happened right
after a takeoff. During my first turn in the pattern, I felt/heard an
unusual noise combined with a slight drop in power. I immediately told the
tower I needed to land and, while keeping an eye on the runway, nervously
made my way around the pattern.

Everything turned out okay, but it took awhile to figure out what was
actually going on. In fact, it turned out to be two completely unrelated
problems. The first, more serious, was a p-lead that was wearing against a
corner, cutting through the insulation and shorting it out. That didn't get
diagnosed for a few months, until it had worn enough to actually show up
during the run-up.

The other problem, that was actually causing the unusual noise I had
noticed, only recently got resolved. After a few years of complaining about
it, and having the airplane inspected thoroughly numerous times in search of
any problems, my mechanics finally discovered two engine mounts that had
been installed backwards. That had misaligned the engine just enough that,
under just the right conditions, some additional engine vibration made it
through the airframe, causing the noise I was feeling and hearing.

I don't know whether those two problems really count as two events, since
they only resulted in the one landing. I'm not even sure that either one on
its own would have scared me enough to get me to land; for sure, the
combination got my instant attention.

There have been other mechanical issues that, thankfully, were caught during
inspections of the airplane (mostly preflights) and which could have easily
turned into unplanned landings. All told, I'd say that 300 hours per might
be a *little* on the high side for *landings*, but it's a pretty good track
record if you're counting ALL mechanical issues that might have forced a
landing, whether you did make an early one or not. In either case, I doubt
it's far from the average. You'd have to have a lot more mechanical
problems than that to warrant being called "unlucky".

Pete