[Milsurplus] Re: APN-1 usage.. was APN-1 vs C-1

[C Whitaker]

de WB2CPN

Ol'  8403, the C-47 I bumed around in a lot, had the indicator
at the navigator's  position.   There was a little telescope that
looked down at the ground as it went under the airplane.  The
navigator could measure drift, and ground speed (TAS) if he knew
how far it was to the ground.  Hence APN-1 and its little
blip on the circle.   Over water an iceberg or waves driven by
the wind helped.   I don't think APN-1 tied into anything, except
maybe a minimum altitude gear warning horn.

Of course, I could be lying.

73  Clete