Airworthiness Directive · Amendment 39-15170 · Boeing Model 777 Airplanes
Boeing Model 777 Airplanes
Superseded. A later AD replaced this one: AD 2009-14-06. Comply with the one in force.
This AD applies to all Boeing Model 777 airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 777 series airplanes. This AD requires, for the drive mechanism of the horizontal stabilizer, repetitive detailed inspections for discrepancies; repetitive lubrication of the ballnut and ballscrew; repetitive measurements of the freeplay between the ballnut and the ballscrew; and corrective action if necessary. This AD results from a report of extensive corrosion of a ballscrew in the drive mechanism of the horizontal stabilizer on a Boeing Model 757 airplane, which is similar in design to the ballscrew on Model 777 airplanes. We are issuing this AD to prevent an undetected failure of the primary load path for the ballscrew in the drive mechanism of the horizontal stabilizer and subsequent wear and failure of the secondary load path, which could lead to loss of control of the horizontal stabilizer and consequent loss of control 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.
The term “service bulletin,” as used in this AD, means Boeing Alert Service Bulletin 777-27A0059, Revision 1, dated August 18, 2005.
Note 1: The service bulletin refers to the Boeing 777 Aircraft Maintenance Manual (AMM), Subjects 12-21-05, 27-41-13, and 29-11-00, as additional sources of service information for accomplishing the actions required by this AD.
For airplanes that have received a certificate of airworthiness prior to the effective date of this AD: Within 180 days or 3,500 flight hours after the effective date of this AD, whichever occurs first, perform a maintenance records check or inspect to determine whether any horizontal stabilizer trim actuator has been replaced for any issue described in the service bulletin with a serviceable actuator that was not new or overhauled, and has not received a detailed inspection and freeplay measurement since the replacement.
Within the compliance times specified in paragraph (h)(1) or (h)(2) of this AD, as applicable: Perform a detailed inspection for discrepancies of the horizontal stabilizer trim actuator ballnut and ballscrew in accordance with Part 1 of the Accomplishment Instructions of the service bulletin. Repeat the detailed inspection thereafter at intervals not to exceed 3,500 flight hours or 12 months, whichever occurs first. If any discrepancy is found during any inspection required by this AD, before further flight, replace the actuator with a new or serviceable actuator in accordance with the Accomplishment Instructions of the service bulletin.
(1) For airplanes identified in paragraph (g) of this AD on which the actuator has not been replaced: Before the accumulation of 15,000 total flight hours, or within 18 months after the effective date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on which the actuator has been replaced, and for airplanes having received a certificate of airworthiness after the effective date of this AD: Before the accumulation of 3,500 flight hours or within 24 months after the effective date of this AD, whichever occurs later.
(i) Within the compliance times specified in paragraph (i)(1) or (i)(2) of this AD, as applicable: Perform a freeplay measurement of the ballnut and ballscrew in accordance with Part 2 of the Accomplishment Instructions of the service bulletin. Repeat the freeplay measurement thereafter at intervals not to exceed 18,000 flight hours or 60 months, whichever occurs first. If the freeplay is found to exceed the limits specified in the service bulletin during any measurement required by this AD, before further flight, replace the actuator with a new or serviceable actuator in accordance with the Accomplishment Instructions of the service bulletin.
(1) For airplanes identified in paragraph (g) of this AD on which the actuator has not been replaced: Before the accumulation of 15,000 total flight hours, or within 18 months after the effective date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on which the actuator has been replaced, and for airplanes having received a certificate of airworthiness after the effective date of this AD: Before the accumulation of 3,500 flight hours or within 24 months after the effective date of this AD, whichever occurs later.
Within the compliance times specified in paragraph (j)(1) or (j)(2) of this AD, as applicable: Lubricate the ballnut and ballscrew in accordance with Part 3 of the Accomplishment Instructions of the service bulletin. Repeat the lubrication thereafter at intervals not to exceed 2,000 flight hours or 12 months, whichever occurs first.
(1) For airplanes identified in paragraph (g) of this AD on which the actuator has not been replaced: Before the accumulation of 15,000 total flight hours, or within 18 months after the effective date of this AD, whichever occurs later.
(2) For airplanes identified in paragraph (g) of this AD on which the actuator has been replaced, and for airplanes having received a certificate of airworthiness after the effective date of this AD: Before the accumulation of 3,500 flight hours or within 24 months after the effective date of this AD, whichever occurs later.
Actions performed prior to the effective date of this AD in accordance with Boeing Alert Service Bulletin 777-27A0059, dated September 18, 2003, are considered acceptable for compliance with the corresponding actions of this AD.
Any actuator overhauled within the compliance times specified in paragraphs (h), (i), and (j) of this AD or before the effective date of this AD—as part of a “hard-time” replacement program that includes removal of the stabilizer actuator from the airplane and overhaul of the stabilizer ballscrew in accordance with original equipment manufacturer component maintenance manual instructions—meets the intent of one detailed inspection, one freeplay inspection, and one lubrication of the stabilizer ballscrew. Therefore, any such actuator is considered acceptable for compliance with the initial accomplishment of the actions specified in paragraphs (h), (i), and (j) of this AD, and repetitions of those actions may be determined from the performance date of that overhaul.
As of the effective date of this AD, no person may install, on any airplane, a horizontal stabilizer trim actuator that is not new or overhauled, unless a detailed inspection, freeplay measurement, and lubrication of that actuator have been performed in accordance with paragraphs (h), (i), and (j) of this AD, as applicable.
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
