Embraer EMB-120 ER, VH-XFX

While cruising at FL140, the pilot in command of the Brasilia noticed a torque drop from 84% to 74% on the right engine. Assuming that the power lever friction was loose and had allowed the engine to creep back from the selected power setting, he readjusted the lever position back to 84% and reset the friction. Approximately 10 seconds later the non-flying pilot remarked that the right engine torque had dropped to 76%. As the pilot in command again went to readjust the torque, the engine lost power. The aircraft then yawed significantly.

The crew then shut down the engine and feathered the propeller. As the aircraft was flying into a 40 to 50 knot headwind, the crew decided to return to the departure airfield.

Company maintenance investigation found that the hydro-mechanical unit (HMU) on the right engine had malfunctioned. The HMU was removed and forwarded to the vendor for further investigation. A serviceable HMU was fitted to the right engine and the aircraft returned to service.