N322SH

On January 9, 2021, about 1000 central standard time, a Robinson R44II helicopter, N322SH, was substantially damaged when it was involved in an accident near Albany, Texas. The pilot and two passengers were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 hog hunting flight.

The pilot reported that it was the second flight of the day. After an uneventful first flight, the helicopter returned to the airport to refuel and pick up new passengers. As the passengers were getting into the helicopter, a rifle was dropped on the dash of the helicopter. “The alt switch, master switch, and clutch [were] switch off” After turning the switches back on, the pilot conducted a “hover power and final systems check.” The helicopter then took off uneventfully. The pilot reported that when 120 ft above the ground, the engine sputtered once then lost complete power. The pilot performed a left turning autorotation to a field. During the descent, the pilot increased the throttle, but the engine did not respond. The helicopter impacted trees before it landed hard on a small mound of dirt and came to rest nose low. The main rotor blade contacted, and severed, the tail boom.

Video of the accident flight begins with the helicopter on the ramp with the engine running with the magneto key in what appears to be the OFF position. In addition, as the pilot shuts down the helicopter after impact, the position of the key did not appear to move despite his fingers touching the key.

During a postaccident examination of the airframe and engine, the helicopter was prepped for an engine run. It started normally and idled for a short time, then a magneto check was conducted. The engine rpm decreased when the key was turned to the left magneto position; however, the rpm remained the same when the right magneto was selected. The key was then moved to the OFF position, and the engine continued to run. The key was jiggled, manipulated, and even removed from the ignition switch, but the engine continued to run. The engine was shut down, and electrical continuity was established from the ignition switch to the magnetos. The grounding wires on the magnetos were examined and appeared to be properly secured. The wires were disconnected; they were pulled and manipulated with no anomalies noted. The magneto grounding wires were tested with a volt/ohm meter and functioned normally. The grounding wires were reinstalled for each magneto and the engine was restarted. It operated normally with several normal magneto checks. The magnetos were removed from the engine and the caps were removed; there were no obvious anomalies noted with the internal components. The ignition switch was also removed and disassembled, with no anomalies noted.

The magnetos were removed for a functional bench test and disassembly. During the bench test, their temperature was increased to 190° F and the magnetos performed normally. Disassembly of the magnetos did not reveal any anomalies with the E-gap, contact settings, condensers, coils, and distributor gear timing that would have precluded normal operations.

In the Robinson R-44II Pilot operating handbook the “STARTING ENGINE AND RUN-UP” checklist includes: “Ignition switch…Prime, then Both,” and “Mag drop at 75% RPM….7% max in 2 seconds.” Both checklist items involve manipulating the key prior to takeoff.