Airworthiness Directive · Amendment 39-15034 · Boeing Model 777-200, 777-300, and 777-300ER Series Airplanes
Boeing Model 777-200, 777-300, and 777-300ER Series Airplanes
This AD applies to Boeing Model 777-200, -300, and -300ER series airplanes, certificated in any category; as identified in Boeing Service Bulletin 777-57-0054, dated February 23, 2006.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 777-200, 777-300, and 777-300ER series airplanes. This AD requires repetitive inspections for discrepancies of the splined components that support the inboard end of the inboard trailing edge flap; related investigative, corrective, and other specified actions if necessary; a one-time modification of the inboard support of the inboard trailing edge flap by installing a new isolation strap and attachment hardware; and repetitive replacement of the torque tube assembly. For certain Boeing Model 777-200 series airplanes, this AD also specifies prior or concurrent accomplishment of one-time inspections of the flap seal panels for cracking and minimum clearances, and of the torque tubes for damage; and related investigative and corrective actions if necessary. This AD also provides a terminating action (modification of the inboard main flap) for the repetitive inspections. This AD results from reports of corrosion on the torque tube and closeout rib fittings that support the inboard end of the inboard trailing edge flap, as well as a structural reassessment of the torque tube joint that revealed the potential for premature fatigue cracking of the torque tube that would not be detected using reasonable inspection methods. We are issuing this AD to detect and correct corrosion or cracking of the torque tube and closeout rib fittings that support the inboard end of the inboard trailing edge flap. Cracking in these components could lead to a fracture, which could result in loss of the inboard trailing edge flap and consequent reduced 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.
The term “service bulletin,” as used in paragraphs (g), (h), (i), (j), and (k) of this AD, means Boeing Service Bulletin 777-57A0048, Revision 1, dated June 9, 2005.
(g) Where the service bulletin specifies a compliance time after the issuance of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
For all airplanes: Do a detailed inspection for any discrepancy of the splined components of the inboard trailing edge flap, in accordance with the Accomplishment Instructions of the service bulletin. The splined components of the inboard trailing edge flap include the torque tube, closeout rib fitting assembly, carrier beam pillow block fitting assembly, and drive crank support. Discrepancies of the torque tube and closeout rib fitting include light contact wear, corrosion pits, corrosion, cracking, or fracture. Discrepancies of the carrier beam pillow block fitting assembly and drive crank support consist of light contact wear and damage to the cadmium plating. Do the initial inspection at the applicable time specified in Table 7 under paragraph 1.E., “Compliance,” of the service bulletin, except as provided by paragraph (g) of this AD. Doing the modification in paragraph (l)(1) of this AD terminates the inspection requirements of this paragraph.
Note 1: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”
(i) If no discrepancy is found during the inspection required by paragraph (h) of this AD, perform all applicable specified actions, including the modification to install a new isolation strap and attachment hardware, in accordance with the Accomplishment Instructions of the service bulletin. Then, repeat the inspection at the applicable time specified in Table 7 under paragraph 1.E., “Compliance,” of the service bulletin. Doing the modification in paragraph (l)(1) of this AD terminates the repetitive inspection requirements of this paragraph.
For any discrepancy found during any inspection required by paragraphs (h) and (i) of this AD: Before further flight, accomplish all applicable related investigative, corrective, and other specified actions, including the modification to install a new isolation strap and attachment hardware, in accordance with the Accomplishment Instructions of the service bulletin. Then, evaluate the spline rework to determine the appropriate repetitive interval, in accordance with the Accomplishment Instructions of the service bulletin. Thereafter, repeat the inspection at the applicable interval specified in Table 7 under paragraph 1.E., “Compliance,” of the service bulletin. Doing the modification in paragraph (l)(1) of this AD terminates the repetitive inspection requirements of this paragraph.
For all airplanes: Replace the torque tube assembly with a new torque tube assembly, in accordance with the Accomplishment Instructions of the service bulletin. Do the initial replacement at the applicable compliance time specified in Notes (c) and (d), as applicable, of Table 7 in paragraph 1.E., “Compliance,” of the service bulletin, except as provided by paragraph (g) of this AD. Repeat the replacement thereafter at the applicable interval specified in Notes (c) and (d), of Table 7 under paragraph 1.E., “Compliance,” of the service bulletin. Doing the modification in paragraph (l)(1) of this AD terminates the repetitive replacement requirements of this paragraph.
For all airplanes: Within 60 months after the effective date of this AD, do the actions in paragraphs (l)(1) and (l)(2) of this AD.
(1) Modify the inboard main flap in accordance with the Accomplishment Instructions of Boeing Service Bulletin 777-57-0054, dated February 23, 2006. Doing this modification terminates the repetitive requirements of paragraphs (i), (j), and (k), of this AD; and inspection requirements of the splined components of the torque tube and the closeout rib fitting assemblies, as required by paragraph (h) of this AD.
(2) Revise the FAA-approved maintenance inspection program for performing periodic inspections and maintenance of the torque tube splined joints in accordance with the Accomplishment Instructions of Boeing Service Bulletin 777-57-0054, dated February 23, 2006. For the purpose of the inspections required by this paragraph, the inspection threshold may be measured from the installation of the modification required by paragraph (l)(1) of this AD.
For Boeing Model 777-200 series airplanes, as identified in Boeing Service Bulletin 777-27-0034, Revision 1, dated April 20, 2006: Prior to or concurrently with the actions in paragraph (l) of this AD, do a general visual inspection of the flap seal panels for cracking and minimum clearances, and a detailed inspection of the torque tubes for damage; and do all applicable related investigative and corrective actions before further flight. Do all actions in accordance with the Accomplishment Instructions of Boeing Service Bulletin 777-27-0034, Revision 1, dated April 20, 2006; except where the service bulletin specifies the corrective action of replacing the torque tube, the replacement must be done in accordance with the Accomplishment Instructions of Boeing Service Bulletin 777-57-0054, dated February 23, 2006.
Note 2: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
Actions done before the effective date of this AD in accordance with Boeing Service Bulletin 777-27-0034, dated February 11, 1999; or Boeing Alert Service Bulletin 777-57A0048, dated September 9, 2004; are acceptable for compliance with the corresponding actions 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.
