In article
,
Mike125 wrote:

On May 1, 12:23*pm, Mike Ash wrote:
In article
,

*Mike125 wrote:
I don't see how a mis-adjusted altimeter gets by the pre-flight
checklist. Instruments: altimeter set to field elevation?

You check it, see that it's a bit off, and set it so that it's correct.

All the while, never noticing that the thousands hand is in the wrong
place.

The human brain has a powerful capacity for illusion. If you "know" that
something is true, it can be difficult to see otherwise. Especially when
the object in question is small and you're not concentrating on it.

I agree anything can happen to anyone, especially me. Having the
altimeter off by 1000' is would be easy to overlook in a hurried
check. Having it off by several hundreds should be caught. I assume
that would grounds for failure on a check ride.

Right, hundreds errors are easy and should always be caught, thousands
errors are tougher. When it happened to me, I think the altimeter was
reading around 0, with field elevation at 700ft. I turned it the quicker
way, ending up with a reading of -300ft, never noticing that the
thousands hand was under the zero. I didn't notice at any time during
the tow either, even though I was watching it in order to release at
3,700ft. It was only after release, when I could relax and take my time,
that I finally noticed that it was reading 1,000ft low.

--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon