Good day, Ken
Example
original built as C-160NG
serial F218 c/n 221 code 64-GR
all C-160 where upgraded with new avionics, they re registered the serial
after upgrade type: C-160R
serial R218 c/n 221 code 64-GR
another on:
original built as C-160F
serial F15 c/n 15 code 61-MJ
after upgrade type: C-160R
serial R15 c/n 15 code 61-MJ
codes started with 61 flying for ET61 airbase Orleans
codes started with 64 flying for ET64 airbase Evreux
regard remco