In the "IGC File Name Decoding Made Easy" it was mentioned about the EW
Avionics recorders (and other recorders) which take a long base10
serial number and convert it to base36 (0-9, a-z) to fit in the file
name format.

"Cambridge, Garrecht (Volkslogger), Zander all use the external serial.
Filser,LX,Colibri,PrintTechnik convert external serial directly to
base36" - Peter Wyld

Peter also comments that depending on the Model of EW recorder, they
take the serial number on the case and add 2000 (B models) or 9000(D
models). A models stay the same. Whew.

From a post by Martin Gregorie I see the following example for an EW
model D

The A line from a trace: AEWAD0430 99429850
The serial number on the case: D0430
The serial number in a filename: 79Y

Taking D0430 and adding 9000 per Peter Wyld's post, I get a base10
serial number of 9430.

Taking 79Y and converting it to Base10.

79Y = 7x36x36 + 9x36 + 34 = 9430. Hey, it works.

All I need now is to get Excel to do the math in reverse and deal with
the add 2000 or 9000 to the SN. I'll report back.

Enjoy, John
johnatderosaweb.com