HELICOPTER PLT WAS FLYING LOW LEVEL AT NIGHT AND STRUCK A POWER LINE.

Narrative

WHILE ON A POLICE PATROL FLT IN THE X VALLEY; I ENTERED A CANYON FROM THE W FOR A FAMILIARIZATION FLT LEG. I MADE A DSNDING L TURN BACK TOWARD THE W; AND BEGAN FOLLOWING THE WASH TO EXIT THE CANYON WBOUND. I FELT WHAT I BELIEVED TO BE A BIRD STRIKE ON THE ACFT. I ASSESSED THE CTL FEEDBACKS AND SCANNED THE INST PANEL. I NOTED NOTHING UNUSUAL IN THE CYCLIC; COLLECTIVE; OR PEDAL CTLS. THERE WAS NO VIBRATION; BUFFETING; OR STIFFNESS; AND ALL ENG; PWR; AND XMISSION GAUGES WERE IN THEIR NORMAL RANGES. I MADE THE DECISION TO LAND AT ZZZ TO INSPECT THE ACFT. I CONTACTED THE ZZZ ATC TWR AND REQUESTED LNDG. ZZZ TWR CLRED ME TO LAND AT THE HELIPADS. I ENTERED A L BASE LEG AND LANDED WITHOUT INCIDENT. ACFT INSPECTION; AND A SUBSEQUENT DEPT INVESTIGATION; REVEALED I HAD STRUCK A RESIDENTIAL PWR LINE. I BELIEVE THIS INCIDENT WAS CAUSED BY A COMBINATION OF MY UNFAMILIARITY WITH THE STRING OF PWR LINES; AND MY LOW RECONNAISSANCE ALT. A HIGHER ALT WHILE IN UNFAMILIAR TERRITORY WILL PREVENT ANY RECURRENCE.