Summary
The FAA proposes to adopt a new airworthiness directive (AD) for all Fokker Model F27 Mark 100, 200, 300, 400, 500, 600, and 700 series airplanes. This proposed AD would require a one-time high-frequency eddy current inspection for cracking of the attachment lugs of the aileron spring tab balance unit, and corrective actions if necessary. This proposed AD is prompted by a report indicating that, during heavy turbulence, a pilot needed to apply aileron trim to maintain level flight because cracking of the upper inboard attachment lug of the aileron spring tab balance unit, probably due to corrosion, had caused permanent deflection of the spring tab and consequent aileron damage. We are proposing this AD to prevent diminished control of the airplane in turbulence or total loss of roll control for the affected wing.