Airworthiness Directive · Amendment 39-16974 · Engine exhaust
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes; certificated in any category; as identified in Boeing Service Bulletin 737-78-1082, dated March 25, 2010.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD was prompted by reports of heat damage to the inner wall of the thrust reversers, which could result in separation of adjacent components and consequent structural damage to the airplane, damage to other airplanes, and injury to people on the ground. This AD requires modifying the thrust reverser inner walls, inspecting for damage of the upper and lower inner wall insulation blankets, measuring the electrical conductivity on the aluminum upper compression pads 2 and 3 as applicable, inspecting for discrepancies of the inner wall of the thrust reverser, and corrective actions if necessary. This AD also requires, for certain airplanes, doing various concurrent actions (including replacing the inner wall blanket insulation, installing updated full-authority digital electronic control software, and modifying the thrust reverser inner wall and insulation blankets). We are issuing this AD to correct the unsafe condition on these products.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Except as required by paragraph (m) of this AD: Within 24 months after the effective date of this AD, modify the thrust reverser inner wall, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1082, dated March 25, 2010.
Before or concurrently with accomplishment of the requirements of paragraph (g) of this AD, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD, as applicable.
(1) For airplanes identified in Boeing Service Bulletin 737-78-1063, Revision 2, dated October 7, 1999: Replace the inner wall blanket insulation, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1063, Revision 2, dated October 7, 1999.
(2) For airplanes equipped with engines identified in CFM CFM56-7B Service Bulletin 73-0135, dated March 30, 2007: Install updated full-authority digital electronic control (FADEC) software, in accordance with the Accomplishment Instructions of CFM CFM56-7B Service Bulletin 73-0135, dated March 30, 2007.
At the applicable time specified in paragraph (j) of this AD: Do the actions specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1088, dated May 12, 2010. If any damage or discrepancy is found, before further flight, do all applicable corrective actions, in accordance with Accomplishment Instructions of Boeing Service Bulletin 737-78-1088, dated May 12, 2010; except as required by paragraph (k) of this AD; and except where the service bulletin refers to “unsatisfactory” findings, this AD assumes those parts or locations are “unserviceable.”
(1) Do a detailed inspection for damage of the engine side and inner wall side of the upper and lower insulation blankets.
(2) Measure the electrical conductivity on the aluminum upper compression pads 2 and 3, as applicable.
(3) Inspect for discrepancies of the thrust reverser inner wall (including an ultrasonic inspection for interply delamination and skin-to-core disbond, a detailed inspection for signs of heat damage as applicable, and a detailed inspection for loose fasteners where the inner wall attaches to the hinge beam and at the fasteners for the compression pads).
Do the actions specified in paragraph (i) of this AD at the applicable time specified in paragraph (j)(1), (j)(2), (j)(3), (j)(4), or (j)(5) of this AD.
(1) For airplanes with thrust reverser part number (P/N) 315A2295-003 through 315A2295-154 inclusive: Do the actions within 30 months after the effective date of this AD.
(2) For airplanes with thrust reverser P/N 315A2295-155 through 315A2295-174 inclusive: Do the actions within 60 months after the effective date of this AD.
(3) For airplanes with thrust reverser P/N 315A2295-175 through 315A2295-190 inclusive: Do the actions within 72 months after the effective date of this AD.
(4) For airplanes with thrust reverser P/N 315A2295-191 through 315A2295-198 inclusive: Do the actions within 84 months after the effective date of this AD.
(5) For airplanes with thrust reverser P/N 315A2295-199 through 315A2295-202 inclusive: Do the actions within 96 months after the effective date of this AD.
Where Boeing Service Bulletin 737-78-1088, dated May 12, 2010, specifies to contact Boeing for appropriate action, repair before further flight in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.
For airplanes identified in Boeing Service Bulletin 737-78-1069, Revision 4, dated June 16, 2005: Before or concurrently with the accomplishment of the requirements of paragraph (i) of this AD, modify the thrust reverser inner wall and insulation blankets, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1069, Revision 4, dated June 16, 2005. This paragraph provides credit for the actions specified in Boeing Service Bulletin 737-78-1069, Revision 4, dated June 16, 2005, if those actions were performed before the effective date of this AD using Boeing Service Bulletin 737-78-1069, Revision 1, dated June 13, 2002; Revision 2, dated February 6, 2003; or Revision 3, dated August 5, 2004.
If the actions required by paragraph (i) of this AD are done before the compliance time specified in paragraph (g) of this AD: Before or concurrently with the accomplishment of the actions required by paragraph (i) of this AD, the modification required by paragraph (g) of this AD must be done.
Accomplishment of all of the actions (including inspections and modification) specified in Boeing Service Bulletin 737-78-1079, Revision 2, dated June 7, 2010, within 24 months after the effective date of this AD, is acceptable for compliance with the requirements of paragraphs (g) and (i) of this AD; except that this AD requires removing the affected compression pads and inspecting the underlying structures regardless whether a pad assembly is made of titanium or aluminum alloy. Accomplishment of all of the actions (including inspections and modification) specified in Boeing Service Bulletin 737-78-1079, Revision 2, dated June 7, 2010, within 24 months after the effective date of this AD, is acceptable for compliance with the requirements of this AD provided applicable repairs are done before further flight, and provided the applicable actions specified in paragraphs (h)(1), (h)(2), and (l) of this AD have been done. This paragraph provides credit for the actions specified in Boeing Service Bulletin 737-78-1079, Revision 2, dated June 7, 2010, if those actions were done before the effective date of this AD using Boeing Service Bulletin 737-78-1079, dated August 6, 2007; or Revision 1, dated December 17, 2007.
