Regarding ATC Involvement :
Let’s look at this with an open mind; ATC was not responsible for this accident, but is one of the holes in the cheese barrier.
Why ? is easy for us (ATC) to understand per perhaps not for all pilots here. So let me explain, so that , at least to those reading this, you might avoid the same fate in the future if you find yourself in a similar situation.
ATC in Europe is multi-layer . Like pancakes belonging to different entities.. For us , TWR, APP, en-route are totally different things . Coordination through the pancakes / entities involves a lot of work. Today many TWR controllers are basically trained for TWR duties only and are not in the loop of what are the procedures done en-route. So much so that they even can belong to different companies with different procedures. An example : In Germany TWR controllers in say, Dortmund, will belong to the TTC company, the middle low level radar centre (until FL240) above it will be located in Bremen, 100 of Kms away, and belonging to the DFS, and the airspace above that will be controlled from Maastricht, in another country belonging to Eurocontrol.
For us ‘ ATC” is not a generic term. And for a pilot Asking “ ATC” or getting approval from “ ATC” means in fact getting approval for the airspace that controller is responsible for, not for the whole flight profile. To a pilot it means differently of course. The telephone conversation between the TWR controller in Perpignan and the Capt is revealing of the misunderstanding to that effect.
Perpignan is a very large airport with very little traffic, like many today in Europe. EAS is one of the main local employer . Relations EAS-ATC are close and everyone wants to help, and assuming the local flexibility will extend further, But what is feasible in that local environment, especially with very low traffic, is not necessarily transposable elsewhere.
The flight plan issue is another good example. It would appear that the XL Captain counted on EAS to do the proper FPL paperwork while EAS expected the Capt or XL Ops to do this. As a result a few ( more than one ) PLNs were filed that day , none of them correctly, in the sense than none described what was intended in reality.
Performing test flights maneuvers in European en-route controlled airspace is very much traffic dependant. Asking this at he time they asked in a busy Bordeaux sector ( Gaillac) was not going to work . Not in France, not in anywhere in core continental Europe for that matter . I have many times in my career authorized Flight tests, but refused a lot too. It depends on the traffic , period. I do not have to provide an alternative neither( I would not know where to send the aircraft to.) if I am busy, my priorities are to separate and expedite the other traffic, and keep the frequency clear, not to engage in Flight tests negotiations on the R/T. Not an excuse, just explaining how we work.
So if you have to perform flight tests , or acceptance tests maneuvers, if it is long ( say more than 10-15 min ), make an airspace reservation request a day or 2 before, like manufacturers and large airlines do,. You will be assigned a reserved airspace and a dedicated frequency to work for as long as you want .
If it is for a short duration, make a RMK in Flied 18 of the PLN indicating what maneuvers you want to perform, and call ( or have your Ops call ) the supervisor of the en route ACC in which airspace (FIR) you intend to perform the tests, and get his approval . He might, like I always did, suggest a quite time period, or an area, where your chances to get what you want are better. The TWR controller is not the best person to do this with.
There is unfortunately far too little “ bridges” between ATC and Flight OPS. ATC is there to help, but certain things are not always feasible as they used to when traffic was lower and available airspace bigger. I find it personally disturbing to see more and more accidents recently where ATC was one of the “holes” in the cheese. Closing a hole is most of the time very easy, but unfortunately afterwards, always afterwards.