NMAC.

Narrative

CLBING OUT OF INDIANAPOLIS (ABOUT 6 MINS AFTER TKOF); WE WERE ON AN ASSIGNED HDG OF 230 DEGS; PASSING THROUGH 9600 FT; I NOTICED A SINGLE ENG; LOW WING ACFT AT OUR 1-2 O'CLOCK POS FLYING DIRECTLY AT US AND JUST SLIGHTLY ABOVE US. AT TIME OF SIGHTING; THE OTHER ACFT WAS ONLY 400-500 FT AWAY. I WAS HAND FLYING AND IMMEDIATELY PUSHED THE NOSE OVER EXPERIENCING SLIGHT NEGATIVE G-FORCE. WE PASSED UNDER THE OTHER ACFT AT AN ESTIMATED 50-100 FT. FROM TIME I SPOTTED THE ACFT UNTIL IT PASSED ABOVE US WAS ABOUT 2-3 SECONDS. OUR HDG AT TIME WAS 230 DEGS; AND OTHER ACFT WAS ON ABOUT A 110 DEG HDG. WE DID NOT SEE OTHER ACFT TAKE AN EVASIVE MANEUVER. THE OTHER ACFT WAS A SINGLE ENG; PROP; LOW WING AND CONVENTIONAL TAIL. IT WAS MOSTLY SILVER/ALUMINUM COLOR WITH A RED/ORANGE NOSE COWL AREA. IT APPEARED TO BE AN OLD MIL TRAINING ACFT. OUR ACFT WAS EQUIPPED WITH TCASII AND IT WAS OPERATING PROPERLY AT THE TIME. WE DID NOT SEE THE ACFT ON OUR TCASII DISPLAY; NOR DID WE RECEIVE AN RA OR TA WARNING. ZID DID NOT HAVE ANY ACFT ON RADAR IN OUR VICINITY. APPARENTLY THE OTHER ACFT DID NOT HAVE A XPONDER OR IT WAS NOT OPERATING. SUGGESTION FOR NON-REOCCURRENCE OF THIS TYPE OF SIT: REQUIRE ALL ACFT TO HAVE AND USE MODE C XPONDER WHILE IN CTLED AIRSPACE.