THE FLT WAS SCHEDULE TO TAKE PSGRS TO A PVT, UNATTENDED, DIRT STRIP NR A WORK SITE. PERMISSION TO LND AT THE STRIP WAS NOT OBTAINED, THO PRIOR PERMISSION WAS REQD. THE STRIP WAS ROUGH; DRAINAGE AT THE APCH END OF RWY 1 HAD ERODED THE GND, MAKING ITS EFFECTIVE LENGTH ABT 2800 FT. ALSO, THERE WAS NO WINDSOCK AT THE STRIP, ITS ELEV WAS 6315 FT & THE DENSITY ALT WAS ABT 9000 FT. A WITNESS RPRTD THE PLT LNDD ON RWY 1, JUST BYD THE MIDPOINT. AFTER TOUCHDOWN, THE ACFT'S WINGS WERE SEEN TO ROCK BACK & FORTH, THEN THE ACFT BCM AIRBORNE AGAIN. DRG A GO-ARND (ABORTED LNDG), THE ACFT WAS CLIMBING OVR RISING TRRN NORTH OF THE STRIP, WHEN IT COLLIDED WITH A POWER LINE (ABT 90 FT ABV THE RWY ELEV) & CRASHED. THE PLT HAD LNDD WITH A SLGT TAILWIND. NO PREIMPACT PART FAILURE/MALFUNCTION OF THE ACFT WAS FND. THE PLT LACKED EXPERIENCE IN LNDG ON SHORT STRIPS WITH HI DENSITY ALT. THE LNDG GEAR & FLAPS WERE FND IN THE RETRACTED PSN. FLAP SETTING OF 10 TO 20 DEG WAS RCMDD FOR SHORT FLD/ROUGH FLD/SOFT FLD/MIN GND RUN TKOF. TKOF DSTC OF 2200 FT WAS REQD TO CLR 50 FT OBSTACLE.