"a" wrote in message
...
A recent thread reminded me it might be worth discussing an personal
flying practice. When en route, as a way of reducing the likelihood
of a midair by about a binary order of magnitude (that's a factor of
two for the non mathematically inclined) I fly the nominal altitude
less 100 feet VFR, or the assigned altitude less 50 feet IFR. The idea
of course is if the unseen/unreported converging traffic is at the
correct altitude or on the high side of it, we'd miss. I chose lower
because I fly a low winged airplane, and of course I would agree this
makes a very unlikely event only slightly less likely. On the other
hand, I don't see that I've significantly increased other in-flight
risks much by doing this, What (if anything) might I have overlooked?
To the wiseguys, yes I in fact do hold altitude pretty closely when
flying.

Even if you do hold altitude pretty closely, it's inevitable you're going to
vary every now and then. As far as IFR goes, 200' altitude deviation busts
are pretty common these days. In theory, you could get busted for a 100'
variation, but I don't know if anyone has ever received a deviation for
such.

One thing to remember is if a controller ever asks, do NOT tell them you are
200' (or more) off your assigned altitude. A good stalling technique is to
ask them for the altimeter setting again and quickly correct while they are
giving it to you. The people who get busted are the ones that fess up.