Federal Aviation Administration July 30, 2007 – Federal Register Recent Federal Regulation Documents

The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 707 airplanes and Model 720 and 720B series airplanes. This proposed AD would require identifying the material used in the elevator hinge support fittings of the horizontal stabilizer trailing edge, doing repetitive detailed inspections for cracking of the fittings and corrective actions if necessary, and doing an eventual terminating action. This proposed AD results from a report that stress corrosion cracking of the elevator hinge support fittings has been discovered on several Model 707 airplanes. We are proposing this AD to prevent cracking of the elevator hinge support fittings, which could reduce the elevator support stiffness and lead to in-flight airframe vibration, consequent damage to the elevator and horizontal stabilizer, and reduced controllability of the airplane.

We are adopting a new airworthiness directive (AD) for the products listed above. 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:

The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This AD requires repetitive high frequency eddy current inspections for cracks of the fuselage skin at stringer 5 left and right between stations 340 and 350, and corrective actions if necessary. This AD results from reports of fatigue cracks in the fuselage skin near stringer 5 between stations 340 and 350. We are issuing this AD to detect and correct fatigue cracking of the fuselage skin near stringer 5. Cracks in this area could join together and result in in-flight depressurization of the airplane.

These special conditions are issued for the Boeing Model 787-8 airplane. This airplane will have novel or unusual design features when compared to the state of technology envisioned in the airworthiness standards for transport category airplanes. These design features include electronic flight control systems and high bypass engines. These special conditions also pertain to the effects of such novel or unusual design features, such as effects on the structural performance of the airplane. Finally, these special conditions pertain to effects of certain conditions on these novel or unusual design features, such as the effects of high intensity radiated fields (HIRF). The applicable airworthiness regulations do not contain adequate or appropriate safety standards for these design features. These special conditions contain the additional safety standards that the Administrator considers necessary to establish a level of safety equivalent to that established by the existing standards. Additional special conditions will be issued for other novel or unusual design features of the Boeing Model 787-8 airplanes.