Hard to comment without further knowing the exact NOTAM and what it raised.
If the NOTAM did not raise an official temporary restricted or otherwise closed for public airspace, the PA may have been absolutely legal to do so, even not very wise in particular. NOticeToAirMen are many times just that, a notice.
Do you have any confirmation the pilot did not recognize the NOTAM, other than not answering a call? If not, there is no real argument he or she didn't see it.
People sometimes misjudge what it means to issue a NOTAM, one part being more responsible for observation within the specific area, not less. The usual NOTAM does not change rules of the air and while display practice training the trainer has to follow see and avoid as normal, even more the area of the NOTAM has been noticed to the public to have them a special lookout. Again, you can interpret a NOTAM as either "please do not enter", emphasis on please, or "this is the area we are practicing and will have a sharp lookout", the viewpoint changes much. What if a complaint is filed and the complainer has to explain why precautions for an official NOTAM area were not taken in a sufficient way to operate on adequate safety, why they decided to not file a NOTAM restricting airspace?
I remember a famous parachute drop little king treating a local parachute area as "his" and the traffic under "his royal kingdom regulations", filing a complaint against a fellow pilot flying through "his area", just to get authorities explain him the nature of "his" parachute area in rude and expensive words.
Flying G without radio contact is absolutely legal, again maybe not very wise. If authorities decide it is necessary to have radio contact, they issue airspace other than G. And, you cannot be sure the pilot did not monitor the frequency. Sometimes it is wiser in the vicinity of a busy airport to keep your mouth shut and not add to radio congestion - pilot decision.
Was a display training frequency issued, maybe even public in NOTAM?
I assume the OP tried to contact the aircraft?
Was this done in a polite and adequate manner, asking whether the aircraft would be so kind to stay outside the area? If it was rude command, I do understand the pilot had no driving force to answer in any way, even more, flying away grumbling over the buttheads down there. Not very helpful ...
More open questions raised than answered, sorry, but I try to understand the exact situation and yes, it may be complicated and even different from what we, the pilot or ATCO feels. Following recent discussions, on particular younger pilots, I read somewhere about the difference of piloting to airmen-ship, mentioning that many airliner-minded pilots rush through the PPL phase and jump very early on ATPL spirit, where timetables and button pushing keeps you from feeling airmen-ship. I somehow like the approach for a discussion and think we should stay at the fraternity of airmen, not converting to bus-like drivers of the air ;-).
Reading "despite a NOTAM warning" in the OP post, I speculate it was just a "notice" NOTAM. Maybe whoever was in the PA decided it is worth a look at the high performance FJ and did not want to congest the radio frequency? Not a decision I would take, but possible and probably totally legal, once again maybe neither wise nor polite from the pilot. But, airmen-ship includes to operate on incomplete information and on personal responsibility on personal decisions and by a good reason.
Personal note.
I do try to read and recognize NOTAMs, but sometimes my decision can be to fly through such a noticed area, sometimes by fault, but sometimes by intention and the respective caution.
I also try to monitor relevant frequencies, but depending on the radios in the aircraft, there is a limit what I am able to follow, my decision which frequencies to monitor also not free of mistakes.
Just from feeling, I do estimate for certain areas there are the same number of aircraft flying through a parachute area with no radio contact as there are parachute machines not giving the appropriate jump notice calls on the radio. As long we all are aware of that, I see no real issue.
A general remark. It always helps to adjust tonality in a call to a legal situation, stay polite and know what you are responsible for. We decided as a society to not lock away anybody at the first sign of weirdness, but this has the side effect of real weirdos walking around - in such a case to remember - always possible on both sides ;-). I am fine with that little freedom to discuss things in person with the relevant people without some far-minded authority representative and don't want to change it, do you?
Last edited by ChickenHouse; 11th Mar 2017 at 08:17.