Airworthiness Directive · Amendment 39-11909 · Boeing Model 777 Series Airplanes
Boeing Model 777 Series Airplanes
Superseded. A later AD replaced this one: AD 2002-11-06, AD 2003-19-02. Comply with the one in force.
Model 777 series airplanes, certificated in any category; having line numbers 1 through 265 inclusive.
Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.
This amendment supersedes an existing airworthiness directive (AD), applicable to all Boeing Model 777 series airplanes. The existing AD requires repetitive detailed visual inspections to detect cracking of the coveskin on the outboard leading edge slats; a slat adjustment check; and corrective actions, if necessary. This amendment reduces the repetitive inspection interval, but also provides for an optional modification that would significantly increase the repetitive inspection interval. This amendment also revises the applicability of the existing AD to remove certain airplanes. This amendment is prompted by findings of increased vibration of the coveskins due to air leaking and resonating within the cavity between the fixed leading edge and the coveskin; the vibration can result in fatigue cracking and high fatigue loads. The actions specified in this AD are intended to detect and correct cracking and/or missing pieces of the coveskin on the outboard leading edge slats on the wings, which could result in skin separation or structural damage to the leading edge slats and consequent reduced controllability of the airplane.
To detect and correct cracking and/or missing pieces of the coveskin on the outboard leading edge slats on the wings, which could result in skin separation or structural damage to the leading edge slats and consequent reduced controllability of the airplane, accomplish the following:
(a) At the applicable time specified by paragraph (a)(1) or (a)(2) of this AD: Perform detailed visual inspections to detect cracking of the coveskin on the outboard leading edge slats of the left and right wings at slat numbers 1 through 6 inclusive, and 9 through 14 inclusive; in accordance with Boeing Alert Service Bulletin 777-57A0034, Revision 2, dated November 19, 1998; Revision 3, dated May 4, 2000; or Revision 4, dated July 20, 2000. Repeat the inspections thereafter at intervals not to exceed 100 flight cycles or 400 flight hours, whichever occurs first.
(1) For airplanes on which the repetitive inspections required by paragraph (a) of AD 99-04-19 HAVE been initiated prior to the effective date of this AD: Inspect at the earlier of the times specified by paragraphs (a)(1)(i) and (a)(1)(ii) of this AD.
(i) Within 350 flight cycles after the most recent inspection.
(ii) At the later of the times specified by paragraphs (a)(1)(ii)(A) and (a)(1)(ii)(B) of this AD.
(A) Within 100 flight cycles or 400 flight hours, whichever occurs first, after the most recent inspection.
(B) Within 30 days after the effective date of this AD.
(2) For airplanes on which the repetitive inspections required by paragraph (a) of AD 99-04-19 have NOT been initiated prior to the effective date of this AD: Inspect at the earlier of the times specified by paragraphs (a)(2)(i) and (a)(2)(ii) of this AD.
(i) Prior to the accumulation of 500 total flight cycles.
(ii) Prior to the accumulation of 2,000 total flight hours, or within 30 days after the effective date of this AD, whichever occurs later.
Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
(b) If any cracking is detected during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish all applicable corrective actions specified by and in accordance with Boeing Alert Service Bulletin 777-57A0034, Revision 2, dated November 19, 1998; Revision 3, dated April 4, 2000; or Revision 4, dated July 20, 2000. The corrective actions include stop drilling the crack and performing detailed visual inspections, slat adjustment checks, and replacement of the slats. Where the alert service bulletin specifies to contact Boeing for appropriate action: Prior to further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office, FAA. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. After the effective date of this AD, only Revision 4 of the alert service bulletin may be used.
(c) Accomplishment of the actions specified by paragraphs (c)(1) and (c)(2) of this AD extends the repetitive inspection interval specified by paragraph (a) of this AD to 8,000 flight cycles.
(1) Install a seal insert into the spanwise bulb seals for the slats in accordance with Part 4 of Boeing Alert Service Bulletin 777-57A0034, Revision 3, dated May 4, 2000; or Revision 4, dated July 20, 2000.
(2) Within 750 days or 4,000 flight cycles, whichever occurs first, after installing the seal insert as specified by paragraph (c)(1) of this AD: Perform a detailed visual inspection of the interior structure of the coveskin at slat numbers 1 through 6 inclusive, and 9 through 14 inclusive, in accordance with Part 2 of the Accomplishment Instructions of the alert service bulletin.
(d)(1) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO.
(2) Alternative methods of compliance, approved previously in accordance with AD 99-04-19, amendment 39-11044, are approved as alternative methods of compliance with paragraph (b) of this AD.
Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.
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
