Airworthiness Directive · Amendment 39-16622 · Stabilizers
The Boeing Company Model 777-200, -200LR, -300, and -300ER Series Airplanes
This AD applies to The Boeing Company Model 777-200, -200LR, -300, and -300ER series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 777-55A0017, dated May 20, 2010.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires repetitive detailed inspections for disbonding and tearing and measurements for wear of the internal diameter (ID) of the Karon-lined bushings of the bulkhead support jackscrew fitting and of the jackscrew fitting of the horizontal stabilizer; and reinstallation of the horizontal stabilizer trim actuator (HSTA) after inspection and measurement; and if necessary, replacement of the bushings with new bushings and all applicable related investigative and corrective actions. This AD was prompted by a report indicating that a Karon-lined bushing with the liner broken into five pieces was found during a scheduled inspection of the HSTA components; the broken liner had worn and disbonded from the bushing. We are issuing this AD to detect and correct discrepancies of the HSTA attachment locations, which could result in reduced structural integrity of the horizontal stabilizer and consequent loss of controllability 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.
Before the accumulation of 32,000 total flight cycles, or within 24 months after the effective date of this AD, whichever occurs later: Do a detailed inspection for disbonding and tearing, and a measurement for wear of the internal diameter (ID) of the Karon-lined bushings of the bulkhead support jackscrew fitting and of the jackscrew fitting of the horizontal stabilizer; replace bushings with new bushings, as applicable; do all applicable related investigative and corrective actions; and install either a known serviceable or overhauled HSTA. Do the actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 777-55A0017, dated May 20, 2010, except as provided by paragraph (h) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the actions required by this paragraph thereafter at intervals not to exceed 16,000 flight cycles.
If, during any inspection or measurement required by this AD, any damage is found, or the inner diameter is greater than the allowable hole diameter, and Part 1, Step 3.B.2.a.(1)(a)1)a) of the Accomplishment Instructions of Boeing Alert Service Bulletin 777-55A0017, dated May 20, 2010, specifies to contact Boeing for appropriate action: Before further flight, do the repair using a method approved in accordance with the procedures specified in paragraph (i) 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
