Airworthiness Directive · Amendment 39-17983 · Nacelles/pylons
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 777-200 and -300 series airplanes, certificated in any category, equipped with Pratt & Whitney PW4000 series engines.
We are superseding Airworthiness Directive (AD) 2013-11-14 for certain The Boeing Company Model 777-200 and -300 series airplanes. AD 2013-11-14 required repetitive general visual inspections of the strut forward dry bay for the presence of hydraulic fluid, and related investigative and corrective actions (including checking drain lines for blockage due to hydraulic fluid coking, and cleaning or replacing drain lines to allow drainage) if necessary. This AD adds airplanes to the applicability. This AD was prompted by reports of hydraulic fluid contamination (including contamination caused by hydraulic fluid in its liquid, vapor, and/or solid (coked) form) found in the strut forward dry bay. We are issuing this AD to detect and correct hydraulic fluid contamination of the strut forward dry bay, which could result in hydrogen embrittlement of the titanium forward engine mount bulkhead fittings, and consequent inability of the fittings to carry engine loads, resulting in engine separation. Hydrogen embrittlement also could cause a through-crack formation across the fittings through which an engine fire could breach into the strut, resulting in an uncontained strut fire.
At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013, except as required by paragraph (h)(1) of this AD: Do a general visual inspection for hydraulic fluid contamination (including contamination caused by hydraulic fluid in its liquid, vapor, and/or solid (coked) form) of the interior of the strut forward dry bay, and do all applicable related investigative and corrective actions (including checking drain lines for blockage due to hydraulic fluid coking, and cleaning or replacing drain lines to allow drainage, as applicable), in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013, except as required by paragraph (h)(2) of this AD. Repeat the inspection thereafter at the times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013. Do all applicable related investigative and corrective actions at the times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013.
(1) Where the Compliance Time column of paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013, refers to the compliance time “after the Revision 1 date of this service bulletin,” this AD requires compliance after the effective date of this AD.
(2) Where Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013, specifies to contact Boeing for repair: At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, Revision 1, dated December 10, 2013, repair, using a method approved in accordance with the procedures specified in paragraph (j) 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.
Aircraft
