Accident Overview
On July 1, 2009, at 0930 mountain daylight time, a Republic RC-3 airplane, registration N87487, was substantially damaged when it struck power lines during takeoff initial climb from the Burley Municipal Airport (BYI), Burley, Idaho. The airplane was registered to and operated by the student pilot under Title 14 Code of Federal Regulations Part 91. The certificated flight instructor sustained serious injuries, and the student pilot sustained minor injuries. Visual meteorological conditions prevailed, and no flight plan was filed for the cross-country flight. The instructional flight was originating at the time of the accident with an intended destination of Caldwell, Idaho.
Pilot Reports
According to the student pilot's written statement, upon arrival at a fixed base operator (FBO) at BYI, the flight instructor requested that the airplane be serviced with 30 gallons of fuel. The student pilot and flight instructor then borrowed a courtesy vehicle and went to a nearby café for breakfast. Upon returning, the student pilot found that the attendant had filled the airplane with 67.70 gallons (full capacity). After asking about siphoning excess fuel, the flight instructor said, "we should be ok." A quick preflight was conducted.
The student pilot reported that before takeoff, the engine sounded normal and the run-up went fine. After verifying the wind direction, the student pilot taxied to runway 24 and began the takeoff. The airplane became airborne about three-quarters of the way down the runway. As it climbed to about 100 feet above ground level (agl), it seemed like it wasn't climbing well. The flight instructor verified throttle, mixture, and propeller control lever positions, noting no change in climb performance. The student pilot stated that the airplane overflew a set of trees and started to settle as if within dead air. Subsequently, the airplane struck power lines about 60 feet in height, 0.7 miles west of the departure end of the runway, and impacted the ground.
In his written statement, the flight instructor reported that prior to arriving at BYI, they refueled at the Preston Municipal Airport (U10), Preston, Idaho. Before departing Preston, he performed a performance calculation to determine aircraft performance at that runway and elevation. During the flight, he noticed the fuel gauge was low and decided to land in Burley for fuel. After learning the airplane had been topped off, he "ran the numbers in his head" and determined it would be fine due to similar conditions as at Preston.
Following a normal run-up, the student pilot taxied into position at the end of runway 24, using all available runway. The flight instructor instructed the student to hold brakes and verify engine RPM of at least 2,300 rpm. As the takeoff roll began, engine gauges indicated normally. The student rotated at 70 mph and climbed at 80 mph. Upon reaching 100 to 150 feet agl, the airplane quit climbing while maintaining 80 mph. Shortly after, airspeed began to decrease, and the airplane began to descend. The flight instructor took control, warned of power lines, and said to brace for impact. The airplane struck the power lines and pitched downward into a vacant lot.
Witness Observations
A witness, an airline transport rated pilot located on the ramp, reported that the airplane appeared to accelerate slowly down runway 24. He estimated it used 85 to 90 percent of the runway before rotating. The airplane climbed at an extremely slow rate, and at about one-quarter to one-half mile from the departure end, it was 60 to 80 feet agl. The witness stated that the pilot attempted to increase the rate of climb twice, resulting in the left wing dipping as it appeared to approach a stall.
Aircraft Examination
Examination by an FAA inspector revealed that the empennage separated from the fuselage aft of the cabin area. The vertical stabilizer and rudder were structurally damaged. Flight control continuity was established from cockpit controls to all primary flight control surfaces. The engine remained attached, and engine control continuity was established. Fuel samples from the aircraft and refueling facility were free of contamination. No mechanical anomalies that would have precluded normal operation were found.
Airport and Weather Information
Burley Municipal Airport's field elevation is 4,150 feet mean sea level (msl). Runway 24 is a 4,067-foot long, 75-foot wide asphalt runway with a 0.2 percent upward gradient. The ASOS at BYI reported at 0853: wind from 260 degrees at 7 knots, visibility 10 statute miles, few clouds at 11,100 feet agl, temperature 19°C, dew point 8°C, altimeter 30.04 inHg.
Performance Calculations
Using a Safety Board computer program, the investigator-in-charge (IIC) calculated density altitude as 5,581 feet and pressure altitude as 4,040 feet. Using the "Distance Required to Takeoff and Clear 50' Obstacle" performance chart for a Republic RC-3 with a Franklin engine, reported weather conditions, reported airplane weight (3,150 pounds, the published maximum gross weight), and calculated pressure altitude, the IIC determined the required distance to clear a 50-foot obstacle was 3,921 feet on a paved surface with gear down and flaps up. The student pilot and flight instructor reported the accident weight as 3,150 pounds.
The Preston Airport (U10) has a field elevation of 4,728 feet msl and two runways: 3/21 (3,457-foot asphalt) and 16/34 (2,437-foot gravel), both with 0.3 percent gradient. The closest weather reporting station was Logan-Cache Airport, 20 miles south, where temperatures varied from 16°C to 18°C between 0451 and 0751 on July 1.