Narrative:

Level at 16000 ft; ZOB asked if we were VMC on top; the first officer answered we were. (It was actually a very clear night.) ATC then informed us we had 2 F16's at our 2 O'clock position approximately 15 mi. (I don't recall the actual phraseology ATC used in relation to their altitude other than that they were above our altitude.) we obtained the visual on the traffic between 10-12 mi as well as a TCAS indication showing the traffic about 1000 ft above our altitude (17000 ft). I directed the first officer to inform ATC we had a visual on the traffic; which he did. ATC then cleared us to maintain visual separation with that traffic and to climb and maintain FL230. With my concurrence the first officer acknowledged the clearance. I inserted FL230 into the FCU; selected 'open' climb. As our aircraft started to climb; the traffic was about 6 mi and appeared to begin a descent. I received a TCAS TA that almost instantly changed to an RA 'descend; increase descent.' upon receiving the RA; we had ascended about 200-300 ft and were between 167200-16300 ft. I immediately began a pushover to descend when the RA changed to 'climb; climb now' and was indicating a maximum climb rate required. I reversed my descent to a climb and within a couple seconds an F16 passed directly under the aircraft from right to left. The first officer saw it and said he heard it. I was monitoring the TCAS and saw the altitude separation decrease to 200 ft. From the beginning of the climb from 16000 ft through the RA maneuvers until passing the F16; I don't believe we ascended or descended more than 300 ft due to the rapid change in direction of the RA from descent to climb. The F16 passed below us at about 16000 ft is my best guess. The F16's were on another frequency or on UHF; we did not know the clearance received by the F16's. I believe a few items could have prevented this occurrence: 1) the fact that both aircraft were not on the same frequency reduced situational awareness of the intentions and clrncs of all aircraft involved. I assume the F16's were on UHF with us on VHF with the controller not simulcasting on both radios. 2) there was no operational necessity to assume visual separation at night with converging traffic. Maintaining IFR separation with ATC would have been much safer; especially at night not having the visual references you would during daylight. 3) once declaring we had the visual with the traffic (we had their lights at between 10-12 mi) for ATC to give us clearance and us to accept a clearance to climb at night through their altitude is an unsafe procedure with converging traffic that will meet within 1 min. This was especially compounded by not having the situational awareness of the radio xmissions; clrncs and intentions of the other aircraft. 4) bottom line: I don't see any operational necessity for an air carrier to accept visual separation at night from other aircraft except possibly in the air traffic area where the route of flight and altitudes are known.

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Original NASA ASRS Text

Title: A320 CAPTAIN; WHILE MAINTAINING VISUAL SEPARATION; REPORTS NMAC WITH AN F16 AT 16000 FEET 30 NM WEST OF DTW.

Narrative: LEVEL AT 16000 FT; ZOB ASKED IF WE WERE VMC ON TOP; THE FO ANSWERED WE WERE. (IT WAS ACTUALLY A VERY CLR NIGHT.) ATC THEN INFORMED US WE HAD 2 F16'S AT OUR 2 O'CLOCK POS APPROX 15 MI. (I DON'T RECALL THE ACTUAL PHRASEOLOGY ATC USED IN RELATION TO THEIR ALT OTHER THAN THAT THEY WERE ABOVE OUR ALT.) WE OBTAINED THE VISUAL ON THE TFC BTWN 10-12 MI AS WELL AS A TCAS INDICATION SHOWING THE TFC ABOUT 1000 FT ABOVE OUR ALT (17000 FT). I DIRECTED THE FO TO INFORM ATC WE HAD A VISUAL ON THE TFC; WHICH HE DID. ATC THEN CLRED US TO MAINTAIN VISUAL SEPARATION WITH THAT TFC AND TO CLB AND MAINTAIN FL230. WITH MY CONCURRENCE THE FO ACKNOWLEDGED THE CLRNC. I INSERTED FL230 INTO THE FCU; SELECTED 'OPEN' CLB. AS OUR ACFT STARTED TO CLB; THE TFC WAS ABOUT 6 MI AND APPEARED TO BEGIN A DSCNT. I RECEIVED A TCAS TA THAT ALMOST INSTANTLY CHANGED TO AN RA 'DSND; INCREASE DSCNT.' UPON RECEIVING THE RA; WE HAD ASCENDED ABOUT 200-300 FT AND WERE BTWN 167200-16300 FT. I IMMEDIATELY BEGAN A PUSHOVER TO DSND WHEN THE RA CHANGED TO 'CLB; CLB NOW' AND WAS INDICATING A MAX CLB RATE REQUIRED. I REVERSED MY DSCNT TO A CLB AND WITHIN A COUPLE SECONDS AN F16 PASSED DIRECTLY UNDER THE ACFT FROM R TO L. THE FO SAW IT AND SAID HE HEARD IT. I WAS MONITORING THE TCAS AND SAW THE ALT SEPARATION DECREASE TO 200 FT. FROM THE BEGINNING OF THE CLB FROM 16000 FT THROUGH THE RA MANEUVERS UNTIL PASSING THE F16; I DON'T BELIEVE WE ASCENDED OR DSNDED MORE THAN 300 FT DUE TO THE RAPID CHANGE IN DIRECTION OF THE RA FROM DSCNT TO CLB. THE F16 PASSED BELOW US AT ABOUT 16000 FT IS MY BEST GUESS. THE F16'S WERE ON ANOTHER FREQ OR ON UHF; WE DID NOT KNOW THE CLRNC RECEIVED BY THE F16'S. I BELIEVE A FEW ITEMS COULD HAVE PREVENTED THIS OCCURRENCE: 1) THE FACT THAT BOTH ACFT WERE NOT ON THE SAME FREQ REDUCED SITUATIONAL AWARENESS OF THE INTENTIONS AND CLRNCS OF ALL ACFT INVOLVED. I ASSUME THE F16'S WERE ON UHF WITH US ON VHF WITH THE CTLR NOT SIMULCASTING ON BOTH RADIOS. 2) THERE WAS NO OPERATIONAL NECESSITY TO ASSUME VISUAL SEPARATION AT NIGHT WITH CONVERGING TFC. MAINTAINING IFR SEPARATION WITH ATC WOULD HAVE BEEN MUCH SAFER; ESPECIALLY AT NIGHT NOT HAVING THE VISUAL REFS YOU WOULD DURING DAYLIGHT. 3) ONCE DECLARING WE HAD THE VISUAL WITH THE TFC (WE HAD THEIR LIGHTS AT BTWN 10-12 MI) FOR ATC TO GIVE US CLRNC AND US TO ACCEPT A CLRNC TO CLB AT NIGHT THROUGH THEIR ALT IS AN UNSAFE PROC WITH CONVERGING TFC THAT WILL MEET WITHIN 1 MIN. THIS WAS ESPECIALLY COMPOUNDED BY NOT HAVING THE SITUATIONAL AWARENESS OF THE RADIO XMISSIONS; CLRNCS AND INTENTIONS OF THE OTHER ACFT. 4) BOTTOM LINE: I DON'T SEE ANY OPERATIONAL NECESSITY FOR AN ACR TO ACCEPT VISUAL SEPARATION AT NIGHT FROM OTHER ACFT EXCEPT POSSIBLY IN THE ATA WHERE THE RTE OF FLT AND ALTS ARE KNOWN.

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