"Neil Gould" wrote in
news
Recently, Andrew Sarangan posted:

My prediction is that GPS will become a standard equipment in the
cockpit, and will replace the magnetic compass. Sure, the GPS can
fail, but those are technical issues which will eventually be solved,
and the GPS will become more reliable than a magnetic compass. My
guess is that it will be 10 years or more before it happens.

To paraphrase this idea; your prediction is that a GPS, which has
thousands of components with complex relationships and therefore
countless failure modes will become more reliable than a magnetic
compass which has only one failure mode -- the loss of fluid.

I doubt it seriously.

Neil







The same thing was said about glass cockpits. Now even the ubiquitous
172 comes with a glass cockpit. It won't be long before the backup
vacuum driven gyros are removed from their panel.

You can't count the number of components in a circuit and assign failure
modes to each one of them. If that were the case, your computer will not
be able to run for even a minute. There are millions of transistors
inside your computer, with million different failure modes. The
traditional method of counting failure modes of mechanical parts do not
apply to highly integrated electronic products. Yes, there are a few
failure modes, but not as large as you make it out to be.