NMAC BTWN A C172 TRAINING FLT AND A PA32 ON AN EXTENDED FINAL FOR RWY 16R AT HEF; VA.

Narrative

ON A VERY CROWDED SUNDAY; I WAS PRACTICING TFC PATTERNS AT HEF ARPT WITH A STUDENT; AND WE ENDED UP UNCOMFORTABLY CLOSE TO ANOTHER ACFT ON FINAL APCH. WE HAD BEEN CLRED FOR TKOF; AND ASKED TO RPT MIDFIELD DOWNWIND. AFTER TKOF AND TURNING XWIND THEN DOWNWIND; FREQ CONGESTION PREVENTED US TO CALL TWR UNTIL WE WERE ABOUT TO TURN BASE. AT THE TIME; ABOUT 5-6 ACFT WERE WAITING TO TAKE OFF. WE RPTED TO TWR; BEING ON AN EXTENDED DOWNWIND; TURNING BASE; AND BEING ON BASE; WITHOUT TWR ACKNOWLEDGING OUR CALLS. WE HEARD TWR CLR ANOTHER ACFT TO LAND AHEAD OF US; AND WE HEARD SEVERAL ACFT RPTING DOWNWIND ON BOTH PARALLEL RWYS. AS WE STARTED TURNING ON AN EXTENDED FINAL; WE HEARD ANOTHER ACFT CALL A TURN FROM BASE TO FINAL; (L PATTERN; WE WERE IN A R PATTERN); AND IMMEDIATELY AFTERWARD; SAW THE SARATOGA PARALLEL TO US ON FINAL; ABOUT 200-400 FT TO OUR L. I IMMEDIATELY RPTED TO TWR BEING ON FINAL WITH TFC PARALLEL; AND SINCE WE HEARD NO RESPONSE; I BEGAN A R TURN AWAY FROM TFC. AS THE SARATOGA CONTINUED AHEAD OF US; I RETURNED TO FINAL; AND PERFORMED SOME S TURNS TO INCREASE SEPARATION. TWR THEN CLRED US TO LAND AFTER THE PIPER; AND THE REST OF THE FLT WAS UNEVENTFUL. THE SIT SEEMS TO HAVE BEEN CAUSED BY EXCESSIVE RADIO CONGESTION; AND BY TWR NOT INSTRUCTING ANY ACFT TO EXTEND THE DOWNWIND LEG FOR TFC.