Narrative:

I was training a transferring cpc at R73. Traffic was light and we were working the sector alone. Aircraft X was being handed off to us from ZZZ2 aproach. His route of flight was ZZZ2..ZZZ3.. Etc. At seven thousand feet. I noticed that this route would take him into ABCDE2 and ABCDE3 which were hot to eight thousand and flight level two three zero; respectively. As a training opportunity; I waited to see if my trainee would catch this bad route. Aircraft X checked on frequency and my trainee acknowledged. My trainee then went around the sector and did several other tasks. I waited for a little bit; and then put a route line up on the scope; so that he could see that the aircraft was headed for the restricted area; which was drawn on the scope. He didn't catch it. My trainee started to hand off aircraft X to ZZZ1 approach; which is where abcde is located. I stopped him at this point and flatly told him that he had to route him around the restricted area. My trainee cleared him direct ZZZ1; direct ZZZ3; rest unchanged. Aircraft X didn't answer. My trainee went on to do something else; and I overrode him and tried again to call aircraft X to no avail. Aircraft X had gone NORAC. We tried through multiple transceivers; and had other airborne aircraft try to raise aircraft X with no luck. I called ZZZ1 approach and told them what was happening. Then I immediately talked to the supervisor and told them that I had a NORDO aircraft headed towards abcde; and that I needed them to call the range to stop their activities. We repeatedly tried to contact aircraft X; still no answer. As aircraft X entered approximately 2 miles into the restricted area; he finally answered a radio call. I immediately turned him due west and climbed him out of the restricted area. I told the pilot that we had made multiple attempts to contact him; but he claimed that he had heard none. We then handed him off to ZZZ1 approach. Recommendation; the aircraft went NORAC after checking on. The guy just quit listening to his radio.

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Original NASA ASRS Text

Title: Enroute Controller providing OJT and wanting to allow the developmental to catch a route error; reported a restricted airspace entry event.

Narrative: I was training a transferring CPC at R73. Traffic was light and we were working the sector alone. Aircraft X was being handed off to us from ZZZ2 Aproach. His route of flight was ZZZ2..ZZZ3.. etc. at seven thousand feet. I noticed that this route would take him into ABCDE2 and ABCDE3 which were hot to eight thousand and flight level two three zero; respectively. As a training opportunity; I waited to see if my trainee would catch this bad route. Aircraft X checked on frequency and my trainee acknowledged. My trainee then went around the sector and did several other tasks. I waited for a little bit; and then put a route line up on the scope; so that he could see that the aircraft was headed for the restricted area; which was drawn on the scope. He didn't catch it. My trainee started to hand off Aircraft X to ZZZ1 approach; which is where ABCDE is located. I stopped him at this point and flatly told him that he had to route him around the restricted area. My trainee cleared him direct ZZZ1; direct ZZZ3; rest unchanged. Aircraft X didn't answer. My trainee went on to do something else; and I overrode him and tried again to call Aircraft X to no avail. Aircraft X had gone NORAC. We tried through multiple transceivers; and had other airborne aircraft try to raise Aircraft X with no luck. I called ZZZ1 Approach and told them what was happening. Then I immediately talked to the supervisor and told them that I had a NORDO aircraft headed towards ABCDE; and that I needed them to call the range to stop their activities. We repeatedly tried to contact Aircraft X; still no answer. As Aircraft X entered approximately 2 miles into the restricted area; he finally answered a radio call. I immediately turned him due West and climbed him out of the restricted area. I told the pilot that we had made multiple attempts to contact him; but he claimed that he had heard none. We then handed him off to ZZZ1 Approach. Recommendation; the aircraft went NORAC after checking on. The guy just quit listening to his radio.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.