Accident Details
The pilot reported that during the initial climb in night visual meteorological conditions, the airplane "was not climbing well." For about 15 minutes, he maneuvered the airplane over a highway, but it still would not gain altitude. Subsequently, he reported being "unable to maintain adequate terrain separation" and landed on the highway. During the landing roll, the pilot swerved to avoid a car and struck a road sign, which substantially damaged the left wing.
Aircraft Weight
In postaccident correspondence, the pilot reported that the airplane was "160 lbs. over gross with high estimates on bags, likely closer to 140 over gross."
Engine Compression Check
The pilot reported that a cold compression check was performed on the engine after the accident. The compressions were 25/80, 42/80, and both rear cylinders were 72/80. The Service Instructions from Textron Lycoming specify that the test should be performed with the engine at normal operating temperatures, but the cylinder compression measured was not completed in accordance with the manufacturer's service instructions.
Environmental Conditions
The density altitude at the time of departure was 8,202 feet, the pressure altitude was 6,217 feet, and the temperature was 20°C (68°F). According to the FAA Koch Chart, the airplane would have likely experienced a 145% increase to the normal takeoff distance and a 65% decrease in a normal climb rate.
Pilot Fatigue
The pilot reported that he had been on a four-day trip and had worked more than 12 hours each day, including the day of the accident. He stated that "fatigue significantly affected decision making as [the] pilot had opportunities to attempt to land back at [the] airport, abort [the] takeoff, or land closer on [the] highway avoiding the vehicle."