PLT OF A HELI PWRLINE PATROL TAKES QUICK EVASIVE ACTION AT 75 FT AGL TO AVOID AN UNKNOWN PWRLINE PERPENDICULAR TO THEIR FLT PATH. THE FORWARD PAX OBSERVER DID OBSERVE THE LINE AHEAD OF TIME BUT DID NOT CALL IT TO THE RPTR'S ATTN.

Narrative

DURING PWRLINE PATROL WITH PLT AND 2 OBSERVERS; ACFT PERFORMED EVASIVE ACTION TO AVOID A SET OF WIRES PERPENDICULAR TO FLT PATH. THE ACFT HAD TURNED W TO FOLLOW PWRLINES THROUGH AN OPEN FIELD. THE ACFT WAS CRABBED INTO THE WIND TO ALLOW A BETTER VIEW FOR THE OBSERVERS; AND HAD FLOWN 600 FT WHEN PLT NOTICED WIRES. PLT LOWERED COLLECTIVE AND BANKED R. AS THE ACFT DSNDED INTO THE OPEN FIELD; THE PLT LEVELED THE ACFT AS THE BACK SKID SKIMMED THE GND. THE PLT BROUGHT THE ACFT TO A HOVER; THEN LANDED. THE PLT AND OBSERVERS DISCUSSED WHAT HAD HAPPENED. THE PLT HAD NOT SEEN THE XING WIRES BECAUSE HE WAS LOOKING L AT BUILDINGS AND SURROUNDING AREAS FOR LIVESTOCK AND FARM ANIMALS SENSITIVE TO NOISE. THE FORWARD OBSERVER HAD SEEN THE XING WIRES UPON TURNING W AND ASSUMED THE PLT HAD SEEN THEM. HE KEPT WAITING FOR PLT TO INCREASE ALT TO OVERFLY THE LINES. THE FORWARD OBSERVER SAID NOTHING DURING THE ENTIRE EPISODE. THE BACK SEAT OBSERVER HAD NOT SEEN THE XING WIRES DUE TO ACFT POS AND OBSTRUCTIONS IN THE ACFT. (IE; FRONT SEAT HEADREST; BOTH FRONT SEAT OCCUPANTS; ETC.) THE PLT AND BACK SEAT OBSERVER HAD FLOWN TOGETHER BEFORE. THIS WAS THE FIRST PATROL FLT FOR THE FORWARD OBSERVER. DURING THE BRIEFING WIRE AVOIDANCE WAS DISCUSSED AND RESPONSIBILITY FOR AVOIDANCE WAS TO BE SHARED BY ALL IN THE ACFT. FACTORS: PLT DISTR BY SECONDARY CONSIDERATIONS (NOISE ABATEMENT). FORWARD OBSERVER'S LACK OF EXPERIENCE -- MAY HAVE BEEN INTIMIDATED TO CALL ATTN TO OBSTACLE.