NMAC BTWN AN SEL SMA ON A NIGHT TRAINING FLT TRANSITING THROUGH CLASS D AIRSPACE AND ANOTHER ACFT CLRED ON THE DOWNWIND LEG FROM THE OPPOSITE DIRECTION.

Narrative

WHILE ON A NIGHT TRAINING FLT; MY STUDENT AND I WERE RETURNING TO OUR BASE ARPT OF 06C FROM MDW VIA TRANSITION THROUGH CGX. AFTER CLRING MDW; WE PROCEEDED TO CONTACT CGX TWR AND REQUEST TRANSITION FROM S TO N AT 1700 FT. OUR REQUEST WAS APPROVED AND WE PROCEEDED TO FOLLOW A COURSE APPROX 3/4 MI E OF CGX RWY 36/18. SHORTLY THEREAFTER; ANOTHER ACFT CONTACTED CGX TWR FROM THE N; INBOUND FOR LNDG. THE TWR CTLR INSTRUCTED THE INBOUND ACFT TO ENTER R TFC FOR RWY 36 AND INFORMED HIM OF TFC OFF HIS L SIDE. THE PLT ACKNOWLEDGED HIS INSTRUCTIONS AND RPTED TFC NOT IN SIGHT. THE CTLR THEN RPTED TO US TFC OFF OUR L SIDE TO WHICH WE RESPONDED; IN SIGHT. MY INITIAL ASSESSMENT OF THE SIT WAS THAT IF BOTH ACFT PROCEEDED ON THEIR PRESENT COURSES; THERE SHOULD BE NO CONFLICT. AS WE APCHED THE OTHER ACFT; WE REALIZED IT WAS MOVING ACROSS OUR COURSE FROM L TO R. WE RESPONDED WITH A L 30 DEG BANK TURN TO AVOID COLLISION AND THE ACFT PASSED OFF OUR R SIDE BY APPROX 300 FT. UPON LATER ANALYSIS OF THE CIRCUMSTANCES WHICH LED TO THE NEAR MISS; I REALIZE THAT WE COULD HAVE BETTER ANTICIPATED THE INTENTIONS OF THE OTHER ACFT AND MADE CORRECTIVE ACTION SOONER. OTHER ACTIONS WHICH COULD HAVE DISSOLVED THE SIT SOONER ARE INCREASED COM ON ALL PARTS (BTWN ACFT AND CTLR).