We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-500 series airplanes. This AD was prompted by reports of chem-mill step cracking on the aft lower lobe fuselage skins. This AD requires inspections of the fuselage skin at the chem- mill steps, and repair if necessary. We are issuing this AD to detect and correct cracking on the aft lower lobe fuselage skins, which could result in decompression of the airplane.
Agency Contact: Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 425- 917-6447; fax: 425-917-6590; email: firstname.lastname@example.org.
This rule is final. Its effective date is September 18, 2012.