twisted engine .. You'll have to untwist on this one. Each aircraft return has a Track Data Block (TDB) associated with it on the radar screens. One of the vital pieces of information the radar controller always displays is the aircraft intention code(destination) in the TDB. Misreading FF for PF would mean the radar controller was preparing to route the aircraft a completely different way. If they made assumptions about climb and descent of other aircraft was based on the expected track of West rather than the actual track of North there could be a serious problem.
This does affect both Planner and Tactical (radar) screens so what the heck does Ian Findlay know about it ?
Moderator I think this belongs in the general pilots area because they should be aware of the problems here. They could just be the one directly affected.