What was found
(CAN) ON DEPARTURE, AT AN ELEVATION OF 900FT AGL PILOT NOTICED LOSS OF POWER AND SUBSEQUENT LOW ROTOR HORN ALARM. PILOT ENTERED AUTO-ROTATION, A/C LANDED WITH MINOR DAMAGE AND NO INJURY TO THE PILOT. PLUMES OF WHITE SMOKE WERE SEEN BY WITNESSES COMING FROM EXHAUST DURING AUTOROTATION AND LANDING - POST INCIDENT, N1 AND N2 DRIVE SYSTEM ROTATE WITH NO ABNORMAL NOISE.