Accident Overview
On September 13, 2012, at about 1400 Alaska daylight time, a wheel/ski equipped Cessna A185F airplane, registration N4786Q, sustained substantial damage following an in-flight collision with an electrical transmission line near Denali Park, Alaska. The certificated commercial pilot was not injured. The airplane was owned by the pilot and operated by Denali Air, Denali Park, as a visual flight rules (VFR) weather observation flight under 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed, and a company VFR flight plan was in effect. The flight originated from the Denali Park Airstrip about 1340.
Flight Details
The pilot stated that the purpose of the flight was to determine if the weather was suitable for flightseeing operations to the glacier east of the Denali Park Airstrip. After assessing conditions, he turned around for the return trip. It is normal procedure to lower the skis while flying over snow in case a landing is needed. When the pilot lowered the skis, he heard an abnormal sound, but everything appeared to operate normally. Upon attempting to raise the skis in preparation for landing, the right ski did not sound or feel normal, and he heard a light popping sound accompanied by oscillations in pitch and yaw.
While troubleshooting the ski issue, the pilot descended below his intended flight path and approached the terrain. As he raised the airplane's nose to climb, a more violent popping and banging occurred, with a loss in airspeed, strong vibration, and a severe yaw to the right.
Pilot's Account
The pilot maintained control and made two passes over the runway at Denali Park Airstrip. He determined that the right ski had deflected to a vertical position. Further attempts to realign the ski were unsuccessful, so he elected to land with the ski vertical. During landing, the right ski folded under the right main landing gear wheel.
On September 14, a representative of the Golden Valley Electric Association delivered a piece of severed transmission tower static cable and a piece of red painted metal resembling an airplane propeller spinner to the FAA Fairbanks Flight Standards District Office. He stated that a power outage occurred around 1400 on September 13 when the severed static cable contacted the main transmission lines of the Alaska Intertie.
In a telephone conversation on September 14 with the NTSB investigator-in-charge, the pilot stated that he was aware of the power line but was not aware that the airplane had made contact with it.
Post-Accident Findings
On September 15, two FAA aviation safety inspectors documented the damage to the airplane. The left wing sustained substantial damage to the leading edge and aileron. Approximately 7 inches of one propeller blade was missing, and there were multiple scratches and gouges in both propeller blades. The right ski had been removed to facilitate moving the airplane; examination revealed a broken bolt connecting the ski to the ski actuator. Multiple scratches and wire abrasion marks were found on the airplane. The left wing had a large gash near the center of the wing, consistent with contact with the power line.