Final Report: Engine-control problems plagued MU-2

 - December 7, 2007, 7:16 AM

Mitsubishi MU-2B-26A, La Verne, Calif., March 27, 2004–The NTSB said the probable cause of the hard landing was the pilot’s failure to compensate adequately for an asymmetrical thrust condition and to maintain directional control during the landing flare. The owner-pilot’s failure to comply with a service bulletin was a factor.

The pilot of the MU-2 noticed that the right engine torque meter read zero when he was about six miles from Brackett Field. When he flared for landing, the airplane yawed to the right despite his trying to correct with left rudder. The airplane landed hard, bounced on the nose twice and broke the nosewheel strut.

After the accident, a ferry pilot flew it for repairs and noted that the engine power levers were consistently split; the right lever had to be about two inches forward of the left to have the engine power parameters match. There was no record of compliance with Mitsubishi Service Bulletin No. 097/73-001, designed to ensure that “the engine and propeller rigging is adjusted within manufacturer’s specifications and to prevent potential degraded flight handling qualities associated with the flight idle power being set asymmetrically or too low.”