Narrative:

I was working an inbound medium large transport into tulsa and stopped his descent at 16000' for a departure off of tulsa (an small transport) climbing to 15000'. They were at a heads up position at approximately 8-10 mi when the medium large transport leveled at 16000' and I noticed the small transport climbing through 15300'. I asked the small transport his altitude and he replied '15500 diving.' traffic had already been issued. I expedited the small transport descent to 15000' and also expedited the medium large transport to climb to 17000' to pull them apart. As far as preventing this occurrence, airlines have altitude alarms they set and GA aircraft could also have them--but whether the GA flying public would use them, I don't know.

Google
 

Original NASA ASRS Text

Title: SMT CLIMBED ABOVE HIS ASSIGNED ALT RESULTING IN LESS THAN STANDARD SEPARATION WITH AN ARR MLG.

Narrative: I WAS WORKING AN INBND MLG INTO TULSA AND STOPPED HIS DSCNT AT 16000' FOR A DEP OFF OF TULSA (AN SMT) CLBING TO 15000'. THEY WERE AT A HEADS UP POS AT APPROX 8-10 MI WHEN THE MLG LEVELED AT 16000' AND I NOTICED THE SMT CLBING THROUGH 15300'. I ASKED THE SMT HIS ALT AND HE REPLIED '15500 DIVING.' TFC HAD ALREADY BEEN ISSUED. I EXPEDITED THE SMT DSCNT TO 15000' AND ALSO EXPEDITED THE MLG TO CLB TO 17000' TO PULL THEM APART. AS FAR AS PREVENTING THIS OCCURRENCE, AIRLINES HAVE ALT ALARMS THEY SET AND GA ACFT COULD ALSO HAVE THEM--BUT WHETHER THE GA FLYING PUBLIC WOULD USE THEM, I DON'T KNOW.

Data retrieved from NASA's ASRS site as of August 2007 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.