Narrative:

Learjet crossed within 4.79 NM of aircraft Y (T1) at FL250 (1000 ft below T1 altitude; but still in the ar block) as aircraft xx transitioned from T2 to T1. Aircraft X had no situational awareness on the learjet traffic as ATC radio was turned down and not updated after cleared to tanker frequency and IFF was in standby per air refueling pre-contact checklist. T1 and T2 had limited situational awareness on the learjet from at and TCAS; but did not pass to aircraft X. For the transition from T1 to T2; military heavy jet formation ar procedures call for R1 to descend 500 ft below T1 altitude; move in line and climb visually. This seems to be the exact moment when the learjet passed underneath aircraft X (FL255) and T2 (FL265); however; I can't be sure. Once in line of T1; aircraft X lost sight due to WX; called blind; descended to FL250 and stopped closure outside of 1 NM using a/a TACAN and WX radar as primary situational awareness tools. This happened sometime shortly after learjet crossed; but nobody (especially zan) was aware of aircraft X's exact position due to lack of squawk during marsa operations. After breaking out of the WX with T1 in sight again -- we continued closure normally for the rest of the track unaware of the possible midair.

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Original NASA ASRS Text

Title: MIL PLT DESCRIBED CONFLICT EVENT WHEN UNKNOWN/UNREPORTED ACFT ENTERED BLOCKED REFUELING AIRSPACE.

Narrative: LEARJET CROSSED WITHIN 4.79 NM OF ACFT Y (T1) AT FL250 (1000 FT BELOW T1 ALT; BUT STILL IN THE AR BLOCK) AS ACFT XX TRANSITIONED FROM T2 TO T1. ACFT X HAD NO SITUATIONAL AWARENESS ON THE LEARJET TFC AS ATC RADIO WAS TURNED DOWN AND NOT UPDATED AFTER CLRED TO TANKER FREQ AND IFF WAS IN STANDBY PER AIR REFUELING PRE-CONTACT CHKLIST. T1 AND T2 HAD LIMITED SITUATIONAL AWARENESS ON THE LEARJET FROM AT AND TCAS; BUT DID NOT PASS TO ACFT X. FOR THE TRANSITION FROM T1 TO T2; MIL HVY JET FORMATION AR PROCS CALL FOR R1 TO DSND 500 FT BELOW T1 ALT; MOVE IN LINE AND CLB VISUALLY. THIS SEEMS TO BE THE EXACT MOMENT WHEN THE LEARJET PASSED UNDERNEATH ACFT X (FL255) AND T2 (FL265); HOWEVER; I CAN'T BE SURE. ONCE IN LINE OF T1; ACFT X LOST SIGHT DUE TO WX; CALLED BLIND; DSNDED TO FL250 AND STOPPED CLOSURE OUTSIDE OF 1 NM USING A/A TACAN AND WX RADAR AS PRIMARY SITUATIONAL AWARENESS TOOLS. THIS HAPPENED SOMETIME SHORTLY AFTER LEARJET CROSSED; BUT NOBODY (ESPECIALLY ZAN) WAS AWARE OF ACFT X'S EXACT POS DUE TO LACK OF SQUAWK DURING MARSA OPS. AFTER BREAKING OUT OF THE WX WITH T1 IN SIGHT AGAIN -- WE CONTINUED CLOSURE NORMALLY FOR THE REST OF THE TRACK UNAWARE OF THE POSSIBLE MIDAIR.

Data retrieved from NASA's ASRS site as of May 2009 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.