Narrative:

B747 was switched to low altitude sector upon reaching FL240. B727 came on frequency climbing through FL226 for FL230. B747 came on frequency high, and I thought low altitude sector would continue his descent to comply with an approach control crossing restr. I climbed B727 to FL260, but saw B747 mode C still indicating FL240. I tried to stop B727 at FL230, but pilot did not respond. I asked low altitude controller if he was descending B747. Controller said he wasn't there. Controller issued descent to B747. Pilot complied, had been waiting for a break in radio congestion? B727 was issued 20 degree left turn and traffic issued, and advised traffic was descending to FL230. B727 reported responding to an RA and he was descending to FL230.

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Original NASA ASRS Text

Title: A CTLR RPT ON LOSS OF SEPARATION BTWN A B747 LEVEL AT FL240 AND A B727 CLBING FROM FL230 TO FL260 15 MI N OF SHB, IN.

Narrative: B747 WAS SWITCHED TO LOW ALT SECTOR UPON REACHING FL240. B727 CAME ON FREQ CLBING THROUGH FL226 FOR FL230. B747 CAME ON FREQ HIGH, AND I THOUGHT LOW ALT SECTOR WOULD CONTINUE HIS DSCNT TO COMPLY WITH AN APCH CTL XING RESTR. I CLBED B727 TO FL260, BUT SAW B747 MODE C STILL INDICATING FL240. I TRIED TO STOP B727 AT FL230, BUT PLT DID NOT RESPOND. I ASKED LOW ALT CTLR IF HE WAS DSNDING B747. CTLR SAID HE WASN'T THERE. CTLR ISSUED DSCNT TO B747. PLT COMPLIED, HAD BEEN WAITING FOR A BREAK IN RADIO CONGESTION? B727 WAS ISSUED 20 DEG L TURN AND TFC ISSUED, AND ADVISED TFC WAS DSNDING TO FL230. B727 RPTED RESPONDING TO AN RA AND HE WAS DSNDING TO FL230.

Data retrieved from NASA's ASRS site as of July 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.