Narrative:

Navy X departed ntu and was climbed to FL160 by orf approach. Center took handoff from orf approach and climbed navy X to FL230. Navy X called center leaving FL227 requesting a higher altitude. I saw a limited data block above X at FL240. I told X he had traffic behind him at FL240 and he would get higher altitude when the traffic passed him. He misunderstood and climbed to FL240. His mode C showed him at FL238 and when I asked him his altitude he said FL240. Callback conversation with reporter revealed following information. Reporter gave years in ATC. Says aircraft Y was also military aircraft swbnd at 6 O'clock to X. Tapes show that when reporter (controller) gave traffic to aircraft X he said traffic at FL240, but pilot of X read back 'climb to FL240' and reporter missed the pertinent part of pilot readback. When both aircraft at FL240 the lateral distance was 4.8 mi. Controller gave location of incident as the orf 290R. High sector working aircraft Y. Facility has not yet completed operation error review.

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Original NASA ASRS Text

Title: LESS THAN STANDARD SEPARATION BETWEEN 2 MIL ACFT. OPERATIONAL ERROR.

Narrative: NAVY X DEPARTED NTU AND WAS CLBED TO FL160 BY ORF APCH. CENTER TOOK HANDOFF FROM ORF APCH AND CLBED NAVY X TO FL230. NAVY X CALLED CENTER LEAVING FL227 REQUESTING A HIGHER ALT. I SAW A LIMITED DATA BLOCK ABOVE X AT FL240. I TOLD X HE HAD TFC BEHIND HIM AT FL240 AND HE WOULD GET HIGHER ALT WHEN THE TFC PASSED HIM. HE MISUNDERSTOOD AND CLBED TO FL240. HIS MODE C SHOWED HIM AT FL238 AND WHEN I ASKED HIM HIS ALT HE SAID FL240. CALLBACK CONVERSATION WITH RPTR REVEALED FOLLOWING INFO. RPTR GAVE YEARS IN ATC. SAYS ACFT Y WAS ALSO MIL ACFT SWBND AT 6 O'CLOCK TO X. TAPES SHOW THAT WHEN RPTR (CTLR) GAVE TFC TO ACFT X HE SAID TFC AT FL240, BUT PLT OF X READ BACK 'CLB TO FL240' AND RPTR MISSED THE PERTINENT PART OF PLT READBACK. WHEN BOTH ACFT AT FL240 THE LATERAL DISTANCE WAS 4.8 MI. CTLR GAVE LOCATION OF INCIDENT AS THE ORF 290R. HIGH SECTOR WORKING ACFT Y. FAC HAS NOT YET COMPLETED OP ERROR REVIEW.

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.