Federal Aviation Administration June 29, 2011 – Federal Register Recent Federal Regulation Documents

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain Model 747 series airplanes. The existing AD currently requires repetitive inspections for cracks of the fuselage skin lap splice between body station (BS) 400 and BS 520 at stringers S-6L and S-6R, and repair if necessary. This proposed AD would shorten the interval for the repetitive inspections, require modification for certain airplanes, and require certain post- modification inspections for other airplanes. This proposed AD results from reports of multiple adjacent cracks on an airplane, and a recent fleet-wide evaluation of widespread fatigue damage of skin lap joints, which indicated the need for revised procedures and reduced compliance times. We are proposing this AD to detect and correct cracking of the fuselage skin lap splice between BS 400 and BS 520 at stringers S-6L and S-6R. Such cracking could result in sudden loss of cabin pressurization and the inability of the fuselage to withstand fail-safe loads.

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated 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:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated 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:

This notice contains a summary of a petition seeking relief from specified requirements of 14 CFR. The purpose of this notice is to improve the public's awareness of, and participation in, this aspect of FAA's regulatory activities. Neither publication of this notice nor the inclusion or omission of information in the summary is intended to affect the legal status of the petition or its final disposition.