Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Fokker Model F27 Mark 050, 100, 200, 300, 400, 600, and 700 series airplanes. This proposal would require an ultrasonic inspection to determine if certain tubes are installed in the drag stay units of the main landing gear (MLG), and various follow-on actions. This proposal is prompted by a report that, due to fatigue cracking from an improperly machined radius of the inner tube, a drag stay broke, and, consequently, lead to the collapse of the MLG during landing. The actions specified by the proposed AD are intended to prevent such fatigue cracking, which could result in reduced structural integrity or collapse of the MLG.