BUT, wasn't that pilot incorrect to say he always maintains the initial restricted altitude
If I was intending to level at 4000 for whatever reason and ATC came back with a "maintain 4000", I would think the exact same. Perhaps I may not make such an RT transmission but never the less I would be thinking the same thing i.e. why is this guy telling me to do something I am already doing - did I make a mistake or did ATC?
If it is true and an aircraft was cleared on a SID that involved a climb through an aircraft at a level that was not separated from the SID then that by definition is a reportable incident because after all if the R/T had failed, that departingaircraft could ahve collided with the survey aircraft wile on the SID.
The answer would be for the aircraft not to have been cleared for the SID in the first place.
Regards,
DFC