What happened
During takeoff from a 4,010-foot runway at an airport elevation of 5,280 feet, the pilot failed to utilize the 10 degrees of flaps recommended by the flight manual. The pilot reported that liftoff occurred at 90 knots. After clearing nearby trees, the pilot retracted the landing gear but noted that the airspeed remained at 90 knots.
The aircraft ceased its climb and subsequently struck a power line. Following the impact, the aircraft settled to the ground with the landing gear in the extended position. Upon touchdown, the landing gear collapsed, causing the aircraft to slide to a stop.
The investigation
The investigation examined the aircraft's backup gear extension system. This system is designed to automatically extend the landing gear when the airspeed drops below a specific threshold, unless the override function is selected. At sea level, the automatic extension speed is 81 knots, increasing linearly to 100 knots at 10,000 feet. At the time of the accident, the density altitude at the airport was approximately 7,000 feet.