Incident Details
A commercial pilot, who also holds a Certified Flight Instructor (CFI) certificate, was conducting a training flight. During single-engine training maneuvers, the left propeller experienced an uncommanded return to flat pitch. The CFI assumed control of the aircraft and executed a precautionary landing to inspect the propeller. Following an extensive engine runup, the CFI decided to attempt a takeoff from a nearby dirt road.
Occurrence During Climb
During the initial climb, at approximately 20 feet above ground level, the left propeller again transitioned to flat pitch. This caused the aircraft to yaw to the left, the left wing to drop, and the airplane to land hard with the landing gear retracted.
Findings
Post-incident inspection revealed that the left propeller dome exhibited evidence of oil leakage over an extended period. The left engine contained only three quarts of oil, which was below the required minimum level. Additionally, one propeller blade on the left engine had a broken pitch change link. The propeller dome was extensively cracked and had begun to disintegrate.
Damage
The hard landing resulted in structural damage: the landing gear, both wings, and the fuselage were bent and twisted.