N3480ECessna 172N · 1978

On July 24, 2010, at 1600 eastern daylight time, a Cessna 172N, N3480E, registered to Apollo Aviation Inc, operating as a 14 Code of Federal Regulations Part 91 personal flight, collided with a fence during takeoff from Eagles Nest Airport (W13), Waynesboro, Virginia. Visual meteorological conditions prevailed and no flight plan was filed. The airplane received substantial damage and the certificated private pilot and two passengers reported no injuries. The flight was originating at the time of the accident.

The pilot stated that prior to departing; he checked the weather and calculated the density altitude of 4, 000 feet using a temperature of 32 to 33 degrees Celsius. He added that the temperature was 99 degrees Fahrenheit. He used 40 degrees Celsius in the pilot operating handbook and determined that the ground roll would be 1,500 feet at an airport elevation of 1,437 feet. In addition, he calculated the weight and balance for the flight and determined that the airplane was below the maximum gross weight.

The pilot and the two passengers entered the airplane and the engine was started. He taxied to the threshold of runway 24, a 2,009-foot-long asphalt runway, which was noted as poor condition. The pilot then continued to taxi back onto the grass overrun area, to obtain an additional 500 feet of runway for takeoff. He completed the engine run-up and no anomalies were noted. The flaps were extended 10 degrees for a short field takeoff. He taxied into position and lined the airplane up for takeoff. The brakes were set, the throttle was increased to full power, and the mixture was leaned to gain better performance at elevations above 3,000 feet. The pilot observed 2,400 rpm on the tachometer, released the brakes, and started the takeoff roll. The initial acceleration was slow through the grass, but once the airplane reached the paved runway, it accelerated normally. The airplane lifted off the runway at 60 knots and remained in ground effect. The airplane would not climb and the pilot turned to the left to avoid some trees. He flew under some power lines, continued straight ahead, and made a forced landing to a field. The airplane collided with a fence, rolled out in a field before colliding with another fence, and came to a stop.

The airport manager at W13, who was also a certified flight instructor, stated the temperature at the time of the pilot's departure was 98 degree Fahrenheit. The density altitude at Shenandoah Valley Airport, located 11 nautical miles northeast of W13, was 4,000 feet. He observed the pilot back taxi down the over-run area, complete an engine run-up, line up, and start the takeoff roll. He immediately wondered why the pilot did not throttle up to full power and assumed he did not want to knick the propeller on anything that might be in the grass. When the airplane reached the runway threshold nothing changed in the way of rpm. About two-thirds down the runway, the pilot forced the airplane into the air, and it wallowed left to right barely flying, and never made it out of ground effect. As the trees at the end of the runway became closer, the nose of the airplane came up, and then it began to settle again. When the second set of trees came up, the nose came up, and the airplane cleared the trees, but settled down out of sight.

Examination of the airplane revealed structural damage to the empennage, fuselage and right elevator. Examination of the engine assembly and accessories revealed no anomalies.

Review of the pilot operating handbook for the Cessna 172N, Section 4, Normal Procedures states in WING FLAP SETTINGS, "Normal and short field takeoffs are performed with flaps up. Flaps greater than 10 degrees are not approved for takeoff. Use of 10 degree flaps is reserved for takeoff from soft or rough fields. Use of 10 degrees flaps allows safe use of approximately 5 KIAS lower takeoff speeds than with flaps up. The lower speeds result in shortening takeoff distances up to approximately 10 percent. However, this advantage is lost if flaps up speeds are used, or in high altitude takeoffs at maximum weight where climb performance would be marginal with 10 degree flaps. Therefore, use of 10 degree flaps is not recommended for takeoff over an obstacle at high altitude in hot weather."

The Federal Aviation Administration Accident Prevention Program for Density Altitude states, "Even at lower elevations, aircraft performance can become marginal and it may be necessary to reduce aircraft gross weight for safe operations. Therefore, it is advisable, when performance is in question, to schedule operations during the cool hours of the day, early morning or late afternoon, when forecast temperatures are expected to rise above normal. Early morning and late evening are sometimes more ideal for both departure and arrival."

The pilot indicated in a statement that the empty weight of the airplane was 1,485 pounds, and that the combined weight of the pilot, front seat passenger and the rear seat passenger was 590 pounds. He had 28 gallons of fuel on board which weighed 168 pounds and 44 pounds of baggage. Subtracting 7 pounds for engine start, taxi, and run up, the takeoff weight was computed at 2,280 pounds. The maximum gross weight for the Cessna 172N is 2,300 pounds. The pilot and passenger were from Holland and returned home. The weights that the pilot provided could not be verified.

Review of the performance data in Section 5 for the TAKEOFF DISTANCE MAXIMUM WEIGHT 2300 LBS SHORT FIELD states in NOTES: "4. For operation on a dry grass runway, increase distances by 15 percent of the ground roll figure." At a gross weight of 2,300 pounds, and a pressure altitude of 1,000 feet, the ground roll at 40 degrees Celsius will be 1,500 feet, and the distance to clear a 50-foot obstacle is 1,865 feet. At a pressure altitude of 2,000 feet, the ground roll will be 1,155 feet, and the distance to clear a 50-foot obstacle is 2,055 feet.