Airworthiness Directive · Amendment 39-15399 · Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 Series Airplanes
Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 Series Airplanes
This AD applies to certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes, certificated in any category; as identified in Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, 737-700, 737-700C, 737-800, and 737-900 series airplanes. This AD requires an inspection of the vertical fin lugs, skin, and skin edges for discrepancies; an inspection of the flight control cables, fittings, and pulleys in section 48 for signs of corrosion; an inspection of the horizontal stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion; and corrective actions if necessary. This AD results from reports indicating that moisture was found within the section 48 cavity. We are issuing this AD to ensure that the correct amount of sealant was applied around the vertical fin lugs, skin and the skin edges. Missing sealant could result in icing of the elevator cables, which could cause a system jam and corrosion of structural and flight control parts, resulting in reduced controllability of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Within 2,500 flight cycles or 18 months after the effective date of this AD, whichever occurs first, do the detailed inspections specified in paragraphs (f)(1), (f)(2), and (f)(3) of this AD in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007.
(1) Do a detailed inspection of the vertical fin lugs, skin, and skin edges for discrepancies (i.e., water ingress; corrosion damage; and missing, insufficient, or cracked sealant).
(2) Do a detailed inspection of the flight control cables, fittings, and pulleys in section 48 for signs of corrosion.
(3) Do a detailed inspection of the horizontal stabilizer jackscrew, ball nut, and gimbal pins for signs of corrosion.
Note 1: For the purposes of this AD, a detailed inspection is: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector (i.e., the person performing the inspection). Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
If any discrepancy or corrosion is found during any inspection required by paragraph (f) of this AD, before further flight, do the applicable corrective actions in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-53A1242, Revision 2, dated April 23, 2007; except where the service bulletin specifies to contact Boeing, repair using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
Actions accomplished before the effective date of this AD in accordance with Boeing Service Bulletin 737-53A1242, dated October 17, 2002; or Revision 1, dated April 28, 2005; are considered acceptable for compliance with the corresponding actions specified in paragraphs (f) and (g) of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
