AD 2021-22-23 Requires Repetitive High Frequency Eddy Current (HFEC) Inspections

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes.

This AD was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting; this finding was on a Model 737-300 series airplane, which has a design similar to the Model 757 airplanes. This AD requires repetitive high frequency eddy current (HFEC) inspections for cracking of the lower aft wing skin aft edge at certain flap tracks, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective December 29, 2021.

Supplementary Information: The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes. The NPRM published in the Federal Register on April 9, 2021 (86 FR 18482). The NPRM was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting. In the NPRM, the FAA proposed to require repetitive HFEC inspections for cracking of the lower aft wing skin aft edge at certain flap tracks, and repair if necessary. The FAA is issuing this AD to address undetected cracking in the lower aft wing  skin, which could result in the inability of the structure to carry limit load and could adversely affect the structural integrity of the airplane.

FMI: www.regulations.gov