Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Fokker Model F28 Mark 0070 and Mark 0100 series airplanes. This proposal would require a one-time visual inspection to detect heat damage of the fuselage skin and stubwing structure. This proposal also would require either repetitive leak tests of the seals of the bleed air system, or repair of any heat- damaged structure, as necessary; and replacement of corrujoint seals with new improved seals. This proposal is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent the leakage of hot air from the corrujoint seals of the low- and high-pressure check valves located in the stubwings, which could result in heat damage to the fuselage skin and stubwing structure, and consequent reduced structural integrity of the airplane.