An interesting conundrum this has thrown up!
We certainly have enough airframes in just about every category to nominate 1 as a training aircraft but if we write yet more rules to stipulate which one it's going to be in each category, there's no guarantee that a different aircraft won't be used. We also have an ongoing problem of pilots leaving the VA for whatever reason and aircraft being left off station without a pilot. Those aircraft could well be training aircraft (should they be nominated) which wouldn't help the situation.Personally, I can't see any good reason to ask for a TR then change aircraft but perhaps that's just me. I presume EDDL - EGCC must be one of the training flights (can't think off the top of my head so I'll check) but if it is, you have to get out there in the first place and not start there as all of our training flights originate in the UK. I also can't remember (god.. isn't poor memory a bind!) where Colin started. It's logical that he could have started at EGCC with AXJK then brought the wrong aircraft back but.. he must have been aware of the rule about not taking an off station aircraft even if he didn't know AVMR should have been left at EDDL. If Colin ended up at EDDL (it will be difficult to tell with him not here).. he should logically have ended up there with AVMR not AXJK.. that is, unless he left another aircraft off station there!
Right.. back to work.. this is too hard
EDIT:
You know what.. I'm not even sure if it should be AVMR now. I've looked at the flights for too long and have lost the plot
One more thing about training aircraft though. It would be possible (though a lot of work) to specify training aircraft for training routes by making a flight available for only one airframe. However, there is no way to stop that aircraft being used on 'full rating' flights should a pilot wish to take it. There are just too many 'live' flights and too many aircraft to make an aircraft from each category not available for full rate flights 
ATB
DaveB
,
If we had 'few' aircraft and 'few' routes, it would be a lot easier to police but we don't have 'few' of either which complicates things. We try and keep 'rules' to a minimum and 'expect' pilots to be predictable and for the most part, it works ok but this sort of thing is always going to happen in an organisation the size of ours with only those regulations in force. The only way around it is to have a nominated aircraft with a specified homebase to cover the nominated routes.. much as we have with the PIA, Chinese and Cyprus Tridents. Those fleets are specific to those areas and for the majority.. there is no crossover. This is open to some abuse/misuse (Cyprus in particular) but by and large.. pilots know where they are, who's routes they're flying and where the homebases are and keep within that remit 
seems I opened quite a can of worms 
