Narrative:

Aircraft #1 en route from northwest direct to helipad sse of airport, initially at 1200 ft MSL. Aircraft #1 being worked by approach control. Aircraft #2 approaching airport for landing on runway 1. Aircraft #2 worked by tower controller. Each aircraft had the other in sight. Due to it being at night, the darkness made it difficult to judge distance and flight path. When aircraft #1 realized their flight paths would cross in proximity to each other, aircraft #1 descended to approximately 800-900 ft MSL, eventually crossing under aircraft #2. Due to the difficulty of judging the flight path of aircraft #2 at night, the descent appeared to be the safest, as a left turn may have been into #2's flight path and a right turn may have placed the helicopter in aircraft #2's wake turbulence. Factors which would have helped include having both aircraft on the same frequency so that each pilot and controller could hear the others for purposes of what each other sees and/or perceives. All should be on 'tower' in the air traffic area and on 'approach' in the class C. Also a better method to cross aircraft from one side of an airport to the other, across approach/takeoff paths while traffic is landing or departing, would be over the center of the airport. This would keep potentially conflicting aircraft out of the approach and takeoff corridors, placing them overhead, whereas the landing/takeoff aircraft would be on the ground.

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Original NASA ASRS Text

Title: NMAC. 2 ACFT APCHING ARPT FROM DIFFERENT DIRECTIONS AND UNDER DIFFERENT CTLR, RPTR ACFT (HELI) CTLED BY TWR AND OTHER ACFT UNDER APCH CTLR. THOUGH BOTH ACFT HAD VISUAL WITH EACH OTHER, RPTR BELIEVED THEY WERE TOO CLOSE IN THE PATTERN AND TOOK EVASIVE ACTION.

Narrative: ACFT #1 ENRTE FROM NW DIRECT TO HELIPAD SSE OF ARPT, INITIALLY AT 1200 FT MSL. ACFT #1 BEING WORKED BY APCH CTL. ACFT #2 APCHING ARPT FOR LNDG ON RWY 1. ACFT #2 WORKED BY TWR CTLR. EACH ACFT HAD THE OTHER IN SIGHT. DUE TO IT BEING AT NIGHT, THE DARKNESS MADE IT DIFFICULT TO JUDGE DISTANCE AND FLT PATH. WHEN ACFT #1 REALIZED THEIR FLT PATHS WOULD CROSS IN PROX TO EACH OTHER, ACFT #1 DSNDED TO APPROX 800-900 FT MSL, EVENTUALLY XING UNDER ACFT #2. DUE TO THE DIFFICULTY OF JUDGING THE FLT PATH OF ACFT #2 AT NIGHT, THE DSCNT APPEARED TO BE THE SAFEST, AS A L TURN MAY HAVE BEEN INTO #2'S FLT PATH AND A R TURN MAY HAVE PLACED THE HELI IN ACFT #2'S WAKE TURB. FACTORS WHICH WOULD HAVE HELPED INCLUDE HAVING BOTH ACFT ON THE SAME FREQ SO THAT EACH PLT AND CTLR COULD HEAR THE OTHERS FOR PURPOSES OF WHAT EACH OTHER SEES AND/OR PERCEIVES. ALL SHOULD BE ON 'TWR' IN THE ATA AND ON 'APCH' IN THE CLASS C. ALSO A BETTER METHOD TO CROSS ACFT FROM ONE SIDE OF AN ARPT TO THE OTHER, ACROSS APCH/TKOF PATHS WHILE TFC IS LNDG OR DEPARTING, WOULD BE OVER THE CTR OF THE ARPT. THIS WOULD KEEP POTENTIALLY CONFLICTING ACFT OUT OF THE APCH AND TKOF CORRIDORS, PLACING THEM OVERHEAD, WHEREAS THE LNDG/TKOF ACFT WOULD BE ON THE GND.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.