Accident Details
On February 7, 2025, at about 1640 central standard time, a Robinson R22 helicopter, registration N7191B, was substantially damaged in an accident near Spearman, Texas. The pilot was not injured, and the passenger sustained minor injuries. The flight was conducted as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Report
The pilot reported departing near Pampa, Texas, at about 1020 for an all-day wildlife management hunting expedition and to inspect fences. While inspecting a fence, the pilot heard a loud bang from the engine, and the helicopter began to shake. The shaking ceased momentarily and then resumed, followed by a total loss of engine power. The pilot was unable to find a suitable forced landing site due to uneven terrain. The helicopter impacted cedar trees and then rolled several times down a hill.
Damage
The helicopter sustained substantial damage to the fuselage, tail boom, and main rotor gearbox.
Engine Inspection
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 securing the intake manifold system to the engine block were found to be loose.
Maintenance History
A review of maintenance records showed that all four engine cylinders were removed for overhaul and reinstalled in June 2024 due to low compression. According to the pilot, who owned the helicopter, in January 2025—about 360 hours after the cylinder overhaul—the No. 1 cylinder was replaced because the intake valve head was 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.