Hi Erich/Alan
Here's the logo for OAMTC
Unless the logic has changed without me noticing, C plus a number will be treated as an IATA code and converted to an ICAO code as defined in the database Airlines table, so, for example C5 will show the logo for UCA - CommutAir.
To get the OAMTC logo to show, Erich will have to edit the Airlines table to convert all the required Cn and Cnn codes to a fake OAMTC three-letter code for the correct logo to show - and then avoid updating the Airlines table in future!
At least C10 - C19 will all be treated as C1, so that will save some work!