Primary finding
Probable cause
Severe propeller and airframe vibration for undetermined reasons. A factor was the lack of suitable terrain for the forced landing.
Investigator assessment
Analysis narrative
Shortly after liftoff, the airplane shook hard, settled, and the right main gear impacted the ground. The airplane then began to climb and the shaking increased. The airplane subsequently settled back down to the ground and collided with a rice levee. The operator reported a loss of power due to a propeller malfunction. An examination of the propeller did not reveal any anomalies that would have contributed to an airplane vibration or power loss.
Source record
Factual narrative
On June 5, 1993, at 1115 central daylight time, a Weatherly 620B, N2002E, sustained substantial damage when it impacted the ground following a loss of power during takeoff. The commercial pilot sustained minor injuries. Visual meteorological conditions prevailed for the local aerial application flight. During a telephone interview, conducted by the Federal Aviation Administration inspector, the operator reported that the airplane hopper was loaded with 1766 pounds of dry fertilizer. The operator stated that immediately after liftoff, the airplane shook "hard", the right wing dropped, and the right main gear contacted the ground about 500 to 600 feet from the point of liftoff. The operator also stated that the airplane bounced and started to climb, but the vibration increased, and it subsequently settled back to the ground, hitting a levee. The operator reported to the investigator in charge that a rod arm bushing assembly linkage for the propeller had failed in flight and the airplane could not sustain flight due to the vibration. An examination of the propeller assembly did not reveal any anomalies that would have contributed to a power loss or vibration. -