Synopsis
A go-around was initiated in high density altitude conditions. The airplane was subsequently observed to enter a shallow climb. It then turned approximately 20 degrees to the right and followed a wide depression in the surrounding terrain without any noticeable gain in altitude.
Flight Sequence
While following the depression, three packages (luggage) were observed being thrown from the right side of the aircraft. After the third package was thrown, the aircraft flew into high voltage power lines. The power lines ran perpendicular to the depression at an altitude of approximately 75 to 100 feet above ground level. The aircraft then impacted the ground and was destroyed by fire.
Power Line Details
No orange balls or other visually alerting devices were attached to the power lines. The power lines were not in a location normally used by low flying aircraft.
Engine Examination
A teardown inspection of the engine did not disclose any mechanical malfunction or abnormal wear. However, the exhaust muffler for the No. 2 and No. 4 cylinders had a partially collapsed internal baffle. Density altitude was about 7,200 feet. Aircraft performance charts indicated that at that altitude, the engine would have been developing only 72 percent of its rated power.