ROBINSON HELICOPTER R22 BETA

Full Narrative

On February 7, 2025, about 1640 central standard time, a Robinson R22 helicopter, N7191B, was substantially damaged when it was involved in an accident near Spearman, Texas. The pilot was not injured, and the passenger sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot reported that they departed near Pampa, Texas, about 1020 for an all-day wildlife management hunting expedition and to inspect fences. While inspecting a fence, the pilot heard a loud bang coming from the engine and the helicopter began to shake. The shaking stopped and then started again, and the engine lost total power. The pilot was unable to find a suitable forced landing site due to uneven terrain, and the helicopter impacted cedar trees and then rolled several times down a hill. The helicopter sustained substantial damage to the fuselage, tail boom, and main rotor gearbox.
A postaccident inspection of the engine revealed that the No. 3 cylinder intake valve head was burned and chipped specifically on the combustion face, margin, and seat face. Additionally, the bolts that secured the intake manifold system to the engine block were loose.
A review of maintenance records revealed that all four engine cylinders were removed for overhaul and reinstalled in June 2024 due to low compression. According to the pilot, who was the owner of the helicopter, in January 2025, about 360 hours after the engine cylinders were overhauled, the No. 1 cylinder was replaced due to the intake valve head being burned. According to the engine manufacturer, when engine cylinders are removed and/or reinstalled, the bolts that secure the intake manifold system to the engine block need to be removed to manipulate the cylinders.