On Mon, 08 Dec 2003 09:26:00 -0500, Roy Smith wrote:

"Trent Moorehead" wrote:
Here's the important step: I checked over the Navigation log to make sure
that it somewhat matched my crude manual numbers.

Excellent idea. The problem with computers is not that they make
errors, but that they don't notice or care if you feed them bad data.
Garbage in, garbage out. Type in the name of a GPS waypoint wrong and
the computer is perfectly happy to send you to Nebraska instead of New
Jersey.

I once sat in the cockpit of an airline flight during the pre-flight
preparations for a flight to Bermuda. Between the plane's computers and
the airline's dispatch department, the flight was planned about as
carefully and accurately as possible. But the pilot still pulled out a
chart and a plotter (looked just like the one you got in your student
pilot kit, except that it had the airline's name printed on it and
looked like it had accumulated a lifetime's worth of dings and
scratches), drew some lines, and went over it leg by leg verifying that
the headings and distances the computer spat out looked reasonable.

This is one of the biggest problems with computers and machines. A
couple of studies about 10 years (or so) back showed that adults are
unlikely to question the output from a computer.

Most adults in the 50 and over group fall into two camps. Those that
can't, or won't use computers, and those who believe them to be
unfailing (Windows aside). Of course there is a small fraction who
believe them to be a creation of the Devil...

Young people are more likely to challenge the output of the computer
unless they are used to variable results as when using GPS, or
devices like computer games.

In between the reaction to faulty output is divided and no real
percentages exist as to how many behave in what way.

The problem is there is a very good chance of people, such as pilots,
accepting faulty output with little or no questioning. Hence it pays
to not only have completely independent navigation systems, but the
ability to fall back on pilotage where possible. Far too many accept
the current systems as their only need due to their reliability and
both let their pilotage skills atrophy and do not use independent
backup systems.

One thing to remember, that like pilotage the back up system does not
need to be as precise as the GPS, only "good enough for who its for".
IE Adequate. OTOH, those who don't trust computers are likely to
ignore inputs that they distrust. (The National Geographic episode
"Flying on Empty" is a prime example) This was the one where the
pilot received the award for the longest glider flight or something
similar.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair?)
www.rogerhalstead.com
Return address modified due to dumb virus checkers