Accident Overview
On January 23, 2022, at approximately 1728 central standard time, a de Havilland Tiger Moth DH-82A, registration N5300, was substantially damaged when it experienced a loss of engine power and subsequently nosed over during a forced landing near Lampasas, Texas. The aircraft was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91. The pilot and the passenger sustained minor injuries.
Flight and Loss of Power
According to the pilot, approximately 20 minutes into the pleasure flight, the engine began to run rough. The pilot immediately turned the aircraft back toward the departure airport, confirmed that the fuel was on, the mixture was rich, and the throttle was open. Despite these actions, the engine continued to lose power. The pilot then decided to divert to a different private airport, but the engine was producing only partial power, insufficient to maintain altitude.
Forced Landing and Accident Sequence
As the aircraft approached the private airport, the pilot perceived that the airplane was too high and initiated a turn. During the turn, he realized he had misjudged the height and determined that completing the turn was not advisable. He leveled the wings and committed to a straight-ahead landing. The terrain in the landing area was terraced. Upon touchdown, the aircraft struck one of the terraced areas, skipped, nosed over, and came to rest inverted.
Damage and Post-Accident Examination
The aircraft sustained substantial damage to the rudder, engine mounts, and lower right wing. After the accident, the pilot, who is also a mechanic, performed an examination of the airplane and engine. He found that the engine could rotate and compression was confirmed on all cylinders. While examining the valve system for the No. 2 cylinder, he discovered that the ball end of the exhaust valve rocker arm was not seated in the end of the pushrod. Additionally, one of the bolts securing the rocker arm assembly had the bolt head separated from its shank. The missing bolt head was located in the rocker cover.