Airworthiness Directive · Amendment 39-16499 · Wings
McDonnell Douglas Corporation Model DC-9-14, DC-9-15, and DC-9-15F Airplanes; and Model DC-9-20, DC-9-30, DC-9-40, and DC-9-50 Series Airplanes
This AD applies to McDonnell Douglas Corporation Model DC-9-14, DC-9-15, DC-9-15F, DC-9-21, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, DC-9-32F (C-9A, C-9B), DC-9-41, and DC-9-51 airplanes; certificated in any category; as identified in Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009.
We are superseding an existing airworthiness directive (AD) for the products listed above. That AD currently requires repetitive high frequency eddy current inspections to detect cracking in the vertical radius (also known as the "vertical leg") of the upper cap of the center wing rear spar, and repair if necessary. This new AD expands the area to be inspected by including inspections to detect cracking of the horizontal flange of the upper cap of the left and right center wing rear spar, and repair if necessary. This new AD also adds certain airplanes to the applicability. This AD was prompted by reports of cracking in the vertical radius of the upper cap of the center wing rear spar, and the horizontal flange on the inboard side of the of the rear spar upper cap, which resulted from stress corrosion. We are issuing this AD to detect and correct cracking in the vertical leg or the horizontal flange of the upper cap of the left or right center wing rear spar, which could cause a possible fuel leak, damage to the wing skin, and structural failure of the upper cap, and result in reduced structural integrity 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.
For all airplanes except Model DC-9-15F airplanes, at the later of the times specified in paragraphs (g)(1) and (g)(2) of this AD: Do a high frequency eddy current inspection to detect cracks in the vertical radius of the upper cap of the center wing rear spar, in accordance with the Accomplishment Instructions of Boeing Service Bulletin DC9-57-223, dated July 21, 2003; or Revision 1, dated August 13, 2009. After the effective date of this AD, only Revision 1 may be used.
(1) Before the accumulation of 25,000 total flight cycles.
(2) Within 15,000 flight cycles or 5 years after December 20, 2004 (the effective date of AD 2004-23-11), whichever occurs first.
(h)(1) If no crack is found during any inspection required by paragraph (g) of this AD, then repeat the inspection thereafter at intervals not to exceed 15,000 flight cycles or 5 years, whichever occurs first, until the initial inspection required by paragraph (i) of this AD is done.
(2) If any crack is found during the inspection required by paragraph (g) of this AD, before further flight, repair per a method approved by the Manager, Los Angeles Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Los Angeles ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.
(i) At the later of the times specified in paragraphs (i)(1) and (i)(2) of this AD: Do a high frequency eddy current inspection to detect cracking in the vertical leg (also known as the “vertical radius”) and horizontal flange of the left and right rear spar upper cap, inboard and outboard sides, at the bulkhead at wing station Xcw=58.500, in accordance with the Accomplishment Instructions of Boeing Service Bulletin DC9-57-223, Revision 1, dated August 13, 2009. If no cracking is found, repeat the inspection thereafter at intervals not to exceed 15,000 flight cycles or 5 years, whichever occurs first. Accomplishment of the initial inspection required by paragraph (i) of this AD terminates the requirements of paragraphs (g) and (h)(1) of this AD.
(1) Before the accumulation of 25,000 total flight cycles.
(2) Within 15,000 flight cycles or 5 years after accomplishing the most recent high frequency eddy current inspection required by paragraph (g) of this AD, whichever occurs first.
If any cracking is found during any inspection required by paragraph (i) of this AD, before further flight, repair the cracking using a method approved in accordance with the procedures specified in paragraph (k) 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.
