Airworthiness Directive · Amendment 39-17708 · Fuselage main bulkhead
The Boeing Company Airplanes
This AD applies to The Boeing Company Model DC-9-11, DC-9-12, DC-9-13, DC-9-14, DC-9-15, and DC-9-15F airplanes, DC-9-31, DC-9-32, DC-9-32 (VC-9C), DC-9-32F, DC-9-33F, DC-9-34, DC-9-34F, and DC-9-32F (C-9A, C-9B) airplanes, and DC-9-41 airplanes, certificated in any category, identified in McDonnell Douglas DC-9 Alert Service Bulletin A53-144, Revision 2, dated February 23, 1984.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model DC-9-10, DC-9-30, and DC-9-40 series airplanes. This AD was prompted by an evaluation by the design approval holder (DAH) indicating that the aft pressure bulkhead web area is subject to widespread fatigue damage (WFD). This AD requires modifying the aft pressure bulkhead. The modification includes inspecting for cracks around the rivet holes, and repair of any cracking. We are issuing this AD to prevent fatigue cracking of the aft pressure bulkhead, which could result in reduced structural integrity of the airplane.
For airplanes on which the modification (AD4 rivets replaced with AD5 rivets) required by AD 85-01-02 R1, Amendment 39-5241 (51 FR 6101, dated February 20, 1986), has not been done: Before the accumulation of 72,000 total flight cycles, or within 18 months after the effective date of this AD, whichever occurs later, modify the aft pressure bulkhead by removing all affected AD4 rivets and doing either a fluorescent penetrant or eddy current inspection around the rivet holes for cracks, repairing any cracking, and installing five-leaf doublers with AD5 rivets, in accordance with the Accomplishment Instructions of McDonnell Douglas DC-9 Alert Service Bulletin A53-144, Revision 2, dated February 23, 1984; except as required by paragraph (h) of this AD.
Note 1 to paragraph (g) of this AD: Information on additional procedures for the modification can be found in Notes 4, 5, and 6, as applicable, of paragraph 1.D., “Compliance” of McDonnell Douglas DC-9 Alert Service Bulletin A53-144, Revision 2, dated February 23, 1984.
If any crack is found during any inspection required by this AD, and McDonnell Douglas DC-9 Alert Service Bulletin A53-144, Revision 2, dated February 23, 1984, specifies to contact the manufacturer for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
Sheet 1 of Service Sketch 3109, and Sheet 7 of Service Sketch 3110B of McDonnell Douglas DC-9 Alert Service Bulletin A53-144, Revision 2, dated February 23, 1984; specify reporting the details of any cracks found; however, this AD does not require reporting.
