AD NUMBER: 2018-01-05

PRODUCT: Certain Fokker Services B.V. Model F28 Mark 0070 and 0100 airplanes.

ACTION: Final Rule; request for comments.

SUMMARY: This AD requires contacting the FAA to obtain instructions for addressing the unsafe condition on these products, and doing the actions specified in those instructions.

This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the fuselage frames are subject to widespread fatigue damage (WFD).

According to the FAA, Fatigue damage can occur locally, in small areas or structural design details, or globally, in widespread areas. Multiple-site damage is widespread damage that occurs in a large structural element such as a single rivet line of a lap splice joining two large skin panels.

Widespread damage can also occur in multiple elements such as adjacent frames or stringers. Multiple-site damage and multiple-element damage cracks are typically too small initially to be reliably detected with normal inspection methods. Without intervention, these cracks will grow, and eventually compromise the structural integrity of the airplane.
 
 This condition is known as WFD. It is associated with general degradation of large areas of structure with similar structural details and stress levels. As an airplane ages, WFD will likely occur, and will certainly occur if the airplane is operated long enough without any intervention.

DATES: This AD becomes effective January 22, 2018. Comments must be received by February 20, 2018.

COST: The FAA estimates that currently, there are no affected U.S.-registered airplanes. For an affected airplane that is placed on the U.S. Register in the future, the cost of compliance would be $27,270 per aircraft for parts and labor.

FMI: AD