AD NUMBER: 2010-22-09

MANUFACTURER: PILATUS Aircraft Ltd. Model PC-7 Airplanes
SUBJECT: Airworthiness Directive 2010-22-09

SUMMARY: This AD results from mandatory continuing airworthiness information (MCAI) issued by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

This Airworthiness Directive (AD) is prompted due to an occurrence when an aircraft had a partial in-flight separation of the aileron outboard bearing support.

The aileron outboard bearing supports are attached with two forward attachment bolts and two aft attachment bolts. The forward attachment bolts are approximately 3.2 mm (0.125 inch) longer than the aft attachment bolts. If the aileron outboard bearing supports have been removed, it is possible that during the reinstallation of the aileron outboard bearing supports, the attachment bolts can be installed in wrong positions. Bolts that are installed in wrong positions can damage the threads in the rear attachment anchor nuts.

Such a condition, if left uncorrected, could lead to in-flight separation of the aileron outboard bearing support, and as a consequence, the loss or limited controllability of the aircraft.

FMI: http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/42D6A93A4313C125862577CB004E7CA7?OpenDocument