Op FERDY was what was colloquially known at Lyneham as the Banner B (ie the Ballykelly runs).
Op BANNER (colloquially known as the Banner A) were the Aldergrove runs.
The Op FERDYs had a particularly 'odd' triangular TACAN let down procedure for when the weather was bad (it certainly did NOT meet APATCE 1 let alone PANSOPS!).
As an aside, I was the Co (along with P... O.... [Obi Wan]) on the crew with the shortest ever groundstop at Ballykelly.
Wheels on to wheels off (with a runway change - we landed on the short, got airborne off the long), 70 odd PAX offloaded, (well) less than 5 minutes on the ground. As operating pilot outbound I was rolling with the 'DOOR OPEN' light still illuminated!
That particular day (Sunday) we pissed off the Staish at Wattisham (but that's another story...)