I've flown in that Devon! Farnborough - Bedford and return for my first day visit after I was posted to Farnborough.
In the days when military aircraft had 5 letter 'registrations' for flying overseas, VP975 was allocated MPDXM hence the 'M' on the fin. All of RAE Farnborough's fleet had one of these registrations starting 'MPDX_' although some were rarely used if ever, with Dakota ZA947 (previously KG661) being allocated MPDXY, Comet XV914 was MPDXA and BAC 1-11 XX919 was MPDXF.
They fell into disuse when RAE was allocated the official ICAO 3 letter designator 'RAE' callsign 'Nugget'.
The only exception as far as I recall was the MRF Hercules which was allocated a Lyneham 'registration' and I have to say I cannot remember what it was!
Nowadays of course, 'M' registrations indicate Isle of Man registry not military!!
Last edited by chevvron; 22nd Oct 2012 at 04:41.