AD 2020-26-09 Requires Repetitive External Surface High Frequency Eddy Current (HFEC) Inspections

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 a report of cracks found in fastener holes at a certain station of the center wing box. This AD requires repetitive external surface high frequency eddy current (HFEC) inspections and repetitive external surface ultrasonic inspections; or repetitive internal detailed inspections; of a certain station of the center wing box for any cracking, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products. This AD is effective January 27, 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 September 22, 2020 (85 FR 59449). The NPRM was prompted by a report of cracks found in fastener holes at a certain station of the center wing box. The NPRM proposed to require repetitive external surface HFEC inspections and repetitive external surface ultrasonic inspections; or repetitive internal detailed inspections; of a certain station of the center wing box for any cracking, and repair if necessary.

The FAA is issuing this AD to address any cracking found in fastener holes at the center wing box, which could result in inability of a principal structural element to sustain limit load and could adversely affect the structural integrity of the airplane.

FMI: www.regulations.gov