NTSB Factual Report

On May 4, 2002, approximately 1400 central daylight time, a Boeing A75SN1, single-engine biplane, N5805V, struck power lines, trees, and a residence following a loss of altitude during takeoff/initial climb from the Georgetown Municipal Airport, near Georgetown, Texas. The airplane was owned and operated by a private individual under 14 Code of Federal Regulations Part 91. The airline transport pilot and the pilot rated passenger/owner received minor injuries. Visual meteorological conditions prevailed for the personal flight, and a flight plan was not filed. The flight was originating at the time of the accident as part of an airshow at the airport.

The pilot-in-command reported that during the takeoff from runway 36, the airplane was number 3 in a formation flight of 4 airplanes. The airplane had a 220 horsepower engine and airplanes 1 and 2 had engines which produced 450 horsepower. During the takeoff/initial climb, the airplane encountered "severe wake turbulence" approximately 100 feet agl. Upon exiting the turbulence, the airplane had "reduced" power and did not maintain altitude. Subsequently, the airplane struck wires, trees, and a house before coming to rest nose low approximately 150 yards beyond the airport property.

The passenger reported that the airplane "lifted off then experienced severe turbulence and seemed to fail obtaining flying speed." The passenger reported clear weather and "no abnormal circumstances." Further, the passenger reported that the engine "seemed to be running smooth at approximately 1,700 rpm."

One witness observed the airplane at less than 100 feet agl in a descending attitude. Subsequently, this witness heard the sound of breaking tree limbs, and observed the airplane descend through the trees to the ground.

Another witness reported the "airplane didn't seem to have any power." This witness heard the airplane "hit and snap the top of the utility pole, the trees breaking, and a loud crack into the house."

The air show operations report stated that the pilot had difficulty from takeoff and a hard time keeping the airplane level. The airplane kept trying to turn left and lost lift. Subsequently, the left main wheel caught the electrical power line, the airplane stalled, struck trees, and a residence before coming to rest in a nose down attitude.

The FAA inspector, who responded to the accident site, found the airplane resting on a measured magnetic heading of approximately 330 degrees approximately 150 yards north of the departure end of runway 36. The right wing fabric was torn, the spar was broken, and the outboard wing was separated from the airframe. The engine remained attached to the airframe, and the propeller blades were found attached at the hub. Flight control continuity was confirmed.

Post accident investigation by the FAA inspector revealed that compression on two of the engine cylinders was below recommended specifications, and one magneto was timed approximately 2 1/2 degrees retarded. According to the FAA inspector, the propeller diameter was longer than the maximum allowable per the Type Certification Data Sheet (TCDS), and the reported take-off and climb rpm of 1700-1800 was lower than the TCDS specification of 2,075 rpm at 220 horsepower.

On July 17, 2002, under the supervision of the FAA inspector, the examination and a teardown of the propeller was performed by the manufacturer at Vandalia, Ohio. According to the manufacturer, "there were no indications of any type of propeller failure prior to impact."

A review of the maintenance records by the FAA inspector revealed that the FAA standard airworthiness certificate was issued in 1981. The airplane was registered to the current owner in 1993. The Continental W670-6N radial engine was removed for overhaul in February 1999. The engine was re-installed in September 1999. The last 100 hour inspection was performed and the airplane returned to service on November 13, 2001.

At 1325 local, the Georgetown weather observation facility reported the wind from 090 degrees at 11 knots with gusts to 18 knots. The visibility was 8 statue miles. The temperature was 84 degrees Fahrenheit, and the density altitude was calculated at 4,200 feet msl.

NTSB Probable Cause

The pilot's inadequate planning/decision resulting in the wake turbulence encounter during the takeoff/initial climb of the formation flight. A contributing factor was the partial loss of engine power for an undetermined reason.