Originally Posted by
Sidestick_n_Rudder
That sounds more like an excercise to check if the pilot under asessment understands what approach clearance is and/or is able to calculate 3 deg path.
Having said that, I still emphasize that CDFA concept is valid from FAF onwards. Before the FAF you are free to descend as you please, as long as you stay at or above the min published altitudes. Both level flight and constant descent before the FAF are perfectly 'kosher', with the latter being a bit more tricky than the former, requiring a bit of practice and vigilance...
This, with emphasis on the part I bolded. Now I'm tempering the strength of my words due to any subtleties I'm not familiar with European procedures, but from what others have posted it seems that it's the same as FAA-land: that an approach clearance
is a clearance to descend to the minimum altitude for any segment that you're established on. So the pilot in the situation was cleared to 2000 once established on the leg prior to the FAF, even though that wasn't explicitly said. So his choice to stay at 2500 was an inappropriate one that set him up for an unstabilized approach, and hopefully lead to an illuminating debrief.
... all assuming that the procedure is indeed the same as in the US.