Airworthiness Directive · Amendment 39-8920 · Mitsubishi Heavy Industries, Ltd. Airplanes
Mitsubishi Heavy Industries, Ltd. Airplanes
This AD applies to Mitsubishi Heavy Industries, Ltd. MU-2B-26A, MU-2B-36, MU-2B-36A, MU-2B-40, MU-2B-60.
The models as the FAA's AD index lists them. The serial ranges, installed parts and exceptions are in the AD itself: read it at the FAA.
This amendment adopts a new airworthiness directive (AD) that applies to certain Mitsubishi Heavy Industries MU-2B series airplanes. This action requires adjusting the engine underspeed governor minimum stop (ground idle) and the airframe condition control linkage, modifying the tachometer indicator markings, fabricating and installing a placard that specifies a minimum idle speed, and incorporating Airplane Flight Manual (AFM) revisions. An accident of one of the affected airplanes where the propeller hub assembly failed and the propeller separated from the airplane prompted this action. Accident investigation analysis indicates a reduction in fatigue strength of the propeller hub because of high vibration frequencies during ground idle speed. The actions specified by this AD are intended to prevent propeller hub arm assembly failure because of high vibration frequencies during ground idle speed and possible separation of the propeller from the airplane, which could result in loss of control of the airplane.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
