AD 2003-02-02

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 and -400D series airplanes, that requires repetitive inspections to detect discrepancies of the drip shield and supports located above the rudder pedal mechanisms; corrective action, if necessary; and eventual modification of the drip shield, which would terminate the repetitive inspections. The actions specified by this AD are intended to prevent unrestrained drip shields from interfering with the rudder pedal mechanism, which could result in reduced controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2003-02-02 Boeing: Amendment 39-13018. Docket 2002-NM-46-AD. \n\n\tApplicability: Model 747-400 and -400D series airplanes, certificated in any category; as listed in Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001. \n\n\tNote 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. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent unrestrained drip shields from interfering with the rudder pedal mechanism, which could result in reduced controllability of the airplane, accomplish the following: \n\nRepetitive Inspections \n\n\t(a) Within 1,200 flight hours after the effective date of this AD: Perform a general visual inspection of the drip shield and supports of the forward rudder quadrant to detect discrepancies (less than 0.50-inch clearance from the components in the forward rudder quadrant, disbonded clip plates, and missing fasteners), in accordance with Figure 1 of the Accomplishment Instructions of Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001, excluding Evaluation Form. \n\n\tNote 2: For the purposes of this AD, a general visual inspection is defined as: "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 enhance visual access to all exposed 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." \n\n\t(1) If no discrepancy is found: Repeat the inspection thereafter at least every 6,000 flight hours or 18 months, whichever is first, until the terminating action required by paragraph (c) of this AD has been accomplished. \n\n\t(2) If any discrepancy is found during any inspection required by this paragraph: Before further flight, perform the specified corrective actions in accordance with Figure 1 of the Accomplishment Instructions of the service bulletin. Thereafter, repeat the inspection at least every 6,000 flight hours or 18 months,whichever is first, until the terminating action required by paragraph (c) of this AD has been accomplished. \n\n\t(b) Accomplishment before the effective date of this AD of an inspection and applicable corrective actions in accordance with Boeing Alert Service Bulletin 747-25A3271, dated April 12, 2001, is acceptable for compliance with the initial inspection requirement of paragraph (a) of this AD. \n\nTerminating Action \n\n\t(c) Within 2 years after the effective date of this AD, modify the drip shield by installing blind rivets in each clip plate and changing the part numbers of the clip plates and drip shield, in accordance with Figure 2 of the Accomplishment Instructions of Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001, excluding Evaluation Form. \n\nAlternative Methods of Compliance \n\n\t(d) 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, SeattleAircraft Certification Office (ACO), FAA. 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. \n\n\tNote 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(f) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing Service Bulletin 747-25A3271, Revision 1, dated December 19, 2001, excluding Evaluation Form. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(g) This amendment becomes effective on February 18, 2003.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747-400 series airplanes was published in the Federal Register on June 28, 2002 (67 FR 43570). That action proposed to require repetitive inspections to detect discrepancies of the drip shield and supports located above the rudder pedal mechanisms; corrective action, if necessary; and eventual modification of the drip shield, which would terminate the repetitive inspections. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. One commenter concurs with the proposed AD. \n\nRequest To Clarify Applicability \n\n\tOne commenter asks that the applicability in the proposed AD be clarified. The commenter suggests adding Model 747-400 series airplanes certificated in the "passenger" category, in lieu of "any" category, to the applicability section. The commenter states that the drip shields referenced in the proposed AD are not installed on Model 747-400F (freighter) series airplanes. \n\n\tWe agree with the commenter that the applicability should be clarified; however, not in the manner proposed. Per the 747 Type Certificate Data Sheet, which specifies Model 747-400, -400D, and -400F series airplanes, we have clarified the applicability throughout this final rule to specify Model 747-400 and -400D series airplanes only. \n\nRequest To Extend Repetitive Inspection Interval \n\n\tOne commenter reiterates the statement in the differences section of the proposed AD that specifies the repetitive inspection interval for the "C-check" as every 3,000 flight hours. The commenter asks that an interval of 6,000 flight hours or 18 months be allowed as a substitute for the "C-check" recommended in the referenced service bulletin, in that it is a more appropriate interval, and appropriately limits both long- and short-haul airplanes. The commenter notes that the Boeing 747-400 Maintenance Planning Document recommends 6,000 flight hours or 18 months as the "C-check" interval, and recent data indicate that the average inspection interval for the fleet is 5,750 flight hours. The commenter adds that imposing an interval of 3,000 flight hours would force some operators to conduct twice as many inspections with less time and manpower available, with no apparent improvement in airplane safety. \n\n\tWe agree with the commenter. Substantiating data were submitted indicating that an extension of the repetitive inspection interval to 6,000 flight hours or 18 months, whichever is first, provides an acceptable level of safety. We find that such an extension in the repetitive inspection interval will allow the inspections to be completed during regularly scheduled maintenance visits. Paragraphs (a)(1) and (a)(2) of this final rule have been changed accordingly. \n\nRequest To Change Certain Wording \n\n\tOne commenter suggests that certain wording specified in Figure 2 of the Accomplishment Instructions of the referenced service bulletin be changed. The note in Figure 2 states, "Plate clips found dis-bonded from the dripshield should be re-installed with rivets." The commenter asks that the word "should" be changed to "must." The commenter does not give a reason for the request. \n\n\tWe do not agree with the commenter. Although the note in Figure 2 of the Accomplishment Instructions of the referenced service bulletin does not definitively specify that discrepant plate clips must be reinstalled with rivets, paragraph (c) of this AD mandates the requirements for installing the rivets. No change to the final rule is necessary in this regard. \n\nChange to Final Rule \n\n\tBecause the language in Note 3 of the proposed AD is regulatory in nature, that note has been redesignated as paragraph (b) of this final rule. Subsequent paragraphs have been reorderedaccordingly. \n\nExplanation of Editorial Change \n\n\tWe have changed the service bulletin citation throughout this final rule to exclude the Evaluation Form. (The form is intended to be completed by operators and submitted to the manufacturer to provide input on the quality of the service bulletin; however, this AD does not include such a requirement.) \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 498 airplanes of the affected design in the worldwide fleet. The FAA estimates that 60 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 1 work hour per airplane to accomplish the inspection,at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required inspection on U.S. operators is estimated to be $3,600, or $60 per airplane, per inspection cycle. \n\n\tIt will take approximately 3 work hours per airplane to accomplish the terminating action, at an average labor rate of $60 per work hour. The cost of required parts will be minimal. Based on these figures, the cost impact of the required terminating action on U.S. operators is estimated to be $10,800, or $180 per airplane. \n\n\tThe cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is containedin the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: