AD 2021-08-12 Prompted By Crack Indications Found In The Lower Aft Wing Skin Bolt Holes

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 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 AD requires repetitive inspections for cracking of the left and right wing, lower aft wing skin aft edge, at certain flap track locations, and applicable on-condition actions. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective May 28, 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 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on July 28, 2020 (85 FR 45355). 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.

The FAA issued a supplemental notice of proposed rulemaking (SNPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The SNPRM published in the Federal Register on January 21, 2021 (86 FR 6276). The SNPRM was prompted by a determination that the compliance time should be reduced for airplanes on which Aviation Partners Boeing (APB) blended winglets have been installed using supplemental type certificate (STC) ST01219SE. The SNPRM proposed to require repetitive inspections for cracking of the left and right wing, lower aft wing skin aft edge, at certain flap track locations, and applicable on-condition actions. The FAA is issuing this AD to address undetected cracking in the lower wing skin, which could result in the inability of the structure to carry limit load, and adversely affect the structural integrity of the airplane.

FMI: www.regulations.gov