FLC OF AN MLG ON DEP CLB AT 1000 FT AGL HAD TCASII RA OF AN ACFT 200 FT BELOW AND SLIGHTLY BEHIND; TO THE SIDE AND ALSO CLBING. THEY THEN OBSERVED A MIL WARTHOG A10 BELOW AND VERY CLOSE OF WHICH THEY ADVISED ATC. ATC THEN ADVISED THE A10 TO LEVEL OFF WHICH ALLOWED RPTR TO CROSS OVER IN THEIR CLB ON FLT PLAN RTE.

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CLRED FOR TKOF FROM RWY 19L IN BOI; CAPT FLYING. NORMAL DEP TO 1000 FT AGL; WHERE CAPT CALLED FOR 'FLAPS 1 DEG; CLB THRUST;' WHICH IS NORMAL FOR OUR PROCS. SIMULTANEOUSLY WITH HIS CALL; WE RECEIVED A TCASII RA OF 'CLB; XING CLB;' AT WHICH POINT THE TCASII SHOWED AN ACFT TARGET BELOW US BY 200 FT AND JUST BARELY BEHIND US OFF THE R. TCASII COMMANDED IN EXCESS OF 3000 FPM RATE OF CLB TO STAY CLR OF THE ACFT; WHICH WE DID NOT KNOW WAS GOING TO BE THERE AND WHICH WE DID NOT HAVE IN SIGHT. ABOUT THE SAME TIME I QUERIED DEP CTL IF HE KNEW OF AN ACFT; I SAW A MIL OV10 BELOW US AND VERY CLOSE ABOARD. DEP INDICATED HE DID NOT KNOW OF THE ACFT UNTIL AFTER WE RECEIVED THE TCASII RA; AT WHICH POINT HE TOLD THE OV10 TO LEVEL OFF SO WE COULD TURN SW TOWARD J7. THE OV10 LEVELED AND WE CONTINUED THE CLB; CLEANING UP AND ACCELERATING IN THE TURN TOWARD J7. (OUR CLRNC WAS RWY HDG; RADAR VECTORS FOR J7; CLB AND MAINTAIN 12000 FT.) APPARENTLY THE OV10 PLT QUERIED IF HE HAD DONE SOMETHING WRONG; AS DEP CTL ANSWERED HIM ON VHF THAT 'NO; HE HAD DONE NOTHING WRONG IN ACCEPTING CLRNC FOR TKOF TO MAINTAIN VISUAL SEPARATION; BUT THE TWR SHOULD HAVE TOLD COMPANY FLT XXXX (US) THAT HE WAS GOING TO BE THERE.' IN MY OPINION; THIS CONSTITUTED A SERIOUS INCIDENT IF FOR NO OTHER REASON THAN THE 'STARTLE FACTOR' DURING A CRITICAL PHASE OF FLT.