Citation III; VI; VII (C650)
Flight Crew Air Transport Pilot (ATP)
Communication Breakdown; Other / Unknown
Conflict NMAC
General Declared Emergency
Aircraft; Human Factors
During our takeoff roll at V1/Vr speed; we experienced an aircraft almost directly in front of our flightpath. We believed it to be the departing training aircraft which departed prior to us which we were told (after the event) had declared an emergency and reversed it's flight path back to the airport environment. The aircraft passed us on our left at an estimated 200-300 FT horizontal distance and 200-300 FT vertical distance. I (PNF-left seat) first saw the approaching aircraft after calling V1/rotate; I looked up and out and visually saw the training aircraft and assumed he saw our departing aircraft for he was not lined up on centerline; but was sidestepped to the left. We did not receive a TA/RA resolution; assuming due to the fact we were still on the squat switch. We continued without altering our departure clearance which was runway heading and a climb to 3;000 FT. We asked for a confirmation of our takeoff clearance with Tower and were told that the aircraft had declared an emergency and reached the airport but was not on Tower frequency and not communicating with Tower.We feel confident the emergency aircraft saw us departing hence his sidestepped position to the runway. Otherwise we feel he would have been on runway centerline attempting a landing to Runway XX; the opposite end of Runway XY. Our best resolution was to continue; although we passed in close proximity; it was obvious our flight paths were not going to intersect and aborting the takeoff above V1/Vr airspeed would actually have been more detrimental to our aircraft. In fact this scenario happened so quickly; we couldn't even collaborate on what was happening until after it happened.
CE650 Captain departing Runway reports an NMAC with a training aircraft returning to land with an emergency on Runway XY. The Tower was not aware of the returning aircraft until after the CE650 had rotated.