Narrative:

I was the trainer on R27/97. During this session we had numerous aircraft with bad routing; spacing requirements; and conflicts. Aircraft X was climbing under aircraft Y from sector 62. My trainee climbed aircraft Y to their requested altitude 27000 feet. When aircraft X checked on frequency the trainee climbed aircraft X to 24000 feet (requesting FL310). Aircraft Y was out of 24600 feet. At this point I knew the aircraft were not an issue with each other and I began to discuss options on how to get the aircraft horizontally separated so that we could get aircraft X up to their requested final altitude of 31000 feet. Initially the trainee requested control for turns (aircraft X) from 62 and assigned a heading 170 to help separate the aircraft and to avoid vance approach control. We then began to again discuss proper routing for aircraft X landing ftw. Along with this discussion we talked spacing into okc with 2 other aircraft we were working.my trainee assigned proper routing to aircraft X which further separated them from aircraft Y. At this point I continued searching for more traffic situations; handoffs; routes; and future aircraft. During my scan the trainee climbed aircraft X. I did not hear what altitude they were climbed to nor did I hear the read back from aircraft X. When my scan returned to aircraft X and aircraft Y; I saw a temporary altitude of 26000 feet in the data block of aircraft X. At that point 26000 feet was 1000 feet below aircraft Y. I did not question/insure that 26000 feet was the altitude that was assigned. Moments later aircraft X's altitude was showing 26200 feet and the conflict alert began to flash. The trainee told aircraft X to maintain 26000 feet. Aircraft X and aircraft Y were continuing to diverge. I asked aircraft X what their last assigned altitude after the trainee assigned 26000 feet they responded that it was 29000 feet. At this point I knew that aircraft X would still be climbing higher before they were able to correct their altitude to 26000 feet. So; I assigned aircraft Y a 15 degree left turn to further the divergence from aircraft X.since I did not hear the altitude the trainee assigned after 24000 feet nor hear the read back from the aircraft; I should have not only confirmed with the trainee the assigned altitude but with the aircraft as well. This could have ensured that aircraft X would have not have climbed beyond 26000 feet. Instead I trusted that the trainee assigned the proper altitude and trusted aircraft X read back the proper altitude.

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Original NASA ASRS Text

Title: A ZKC Controller reported a miscommunication between a trainee and the flight crew of a climbing aircraft. The aircraft climbed above the intended altitude causing a loss of separation.

Narrative: I was the trainer on R27/97. During this session we had numerous aircraft with bad routing; spacing requirements; and conflicts. Aircraft X was climbing under Aircraft Y from sector 62. My trainee climbed Aircraft Y to their requested altitude 27000 feet. When Aircraft X checked on frequency the trainee climbed Aircraft X to 24000 feet (requesting FL310). Aircraft Y was out of 24600 feet. At this point I knew the aircraft were not an issue with each other and I began to discuss options on how to get the aircraft horizontally separated so that we could get Aircraft X up to their requested final altitude of 31000 feet. Initially the trainee requested control for turns (Aircraft X) from 62 and assigned a heading 170 to help separate the aircraft and to avoid Vance approach control. We then began to again discuss proper routing for Aircraft X landing FTW. Along with this discussion we talked spacing into OKC with 2 other aircraft we were working.My trainee assigned proper routing to Aircraft X which further separated them from Aircraft Y. At this point I continued searching for more traffic situations; handoffs; routes; and future aircraft. During my scan the trainee climbed Aircraft X. I did not hear what altitude they were climbed to nor did I hear the read back from Aircraft X. When my scan returned to Aircraft X and Aircraft Y; I saw a temporary altitude of 26000 feet in the data block of Aircraft X. At that point 26000 feet was 1000 feet below Aircraft Y. I did not question/insure that 26000 feet was the altitude that was assigned. Moments later Aircraft X's altitude was showing 26200 feet and the conflict alert began to flash. The trainee told Aircraft X to maintain 26000 feet. Aircraft X and Aircraft Y were continuing to diverge. I asked Aircraft X what their last assigned altitude after the trainee assigned 26000 feet they responded that it was 29000 feet. At this point I knew that Aircraft X would still be climbing higher before they were able to correct their altitude to 26000 feet. So; I assigned Aircraft Y a 15 degree left turn to further the divergence from Aircraft X.Since I did not hear the altitude the trainee assigned after 24000 feet nor hear the read back from the aircraft; I should have not only confirmed with the trainee the assigned altitude but with the aircraft as well. This could have ensured that Aircraft X would have not have climbed beyond 26000 feet. Instead I trusted that the trainee assigned the proper altitude and trusted Aircraft X read back the proper altitude.

Data retrieved from NASA's ASRS site 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.