Airworthiness Directive · Amendment 39-17474 · Nacelles/pylons
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2014-20-10. Comply with the one in force.
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; as identified in Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 777-200 and -300 series airplanes. 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. This AD requires 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. 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. Hydraulic 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.
Except as provided by paragraph (h)(1) of this AD, at the times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012: 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) if necessary, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012, 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, dated May 25, 2012. Except as required by paragraph (h)(3) of this AD, 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, dated May 25, 2012.
(1) Where the Compliance time column of paragraph 1.E., “Compliance,” of Boeing Service Bulletin 777-54-0028, dated May 25, 2012, refers to the compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) Where Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012, specifies to contact Boeing for repair: Except as required by paragraph (h)(3) of this AD, at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012, repair, using a method approved in accordance with the procedures specified in paragraph (i) of this AD.
(3) Where paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 777-54-0028, dated May 25, 2012, specifies a compliance time of “within 25 flight-cycles or 10 days, whichever occurs first,” this AD requires compliance within 25 flight cycles or 10 days after the most recent inspection required by paragraph (g) of this AD, whichever occurs first.
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
