AD 99-11-14

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires detailed visual inspections to detect corrosion or chrome plating cracks on the fuse pins of the outboard support of the main landing gear (MLG) beam. This AD also would require either installation of the existing fuse pins and repetitive inspections; or installation of newer-type fuse pins, which constitutes terminating action for the repetitive inspections. This amendment is prompted by a report indicating that corrosion was found on a fuse pin in the outboard support of the MLG beam. The actions specified by this AD are intended to detect and correct such corrosion and cracking, which could result in the failure of a fuse pin and, consequently, lead to collapse of the MLG.

Final rule

99-11-14 BOEING: Amendment 39-11185. Docket 97-NM-51-AD. \n\n\tApplicability: Model 767 series airplanes, line numbers 1 through 609 inclusive; certificated in any category; having 4330M steel fuse pins installed in the outboard support of the main landing gear (MLG) beam. \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 actionsto address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct corrosion and cracking of the fuse pins in the outboard support of the MLG beam, which could result in the failure of a fuse pin and, consequently, lead to collapse of the MLG, accomplish the following: \n\nDetailed Visual Inspection \n\n\t(a)\tWithin 4 years of service since the MLG was new, or within 18 months after the effective date of this AD, whichever occurs later, perform detailed visual inspections of the fuse pins of the MLG outboard support beam to detect corrosion or chrome plating cracks on the fuse pin, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1996, or Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997. \n\n\tNOTE 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." \n\nCorrective Actions \n\n\t(b)\tIf any corrosion or plating crack of a fuse pin is found during any inspection required by paragraph (a) of this AD, prior to further flight, accomplish either paragraph (b)(1) or (b)(2) of this AD. \n\n\t\t(1)\tInstall a new or serviceable 4330M steel fuse pin in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1996, or Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997. Repeat the detailed visual inspections required by paragraph (a) of this AD thereafter at intervals not to exceed 48 months. Or \n\n\t\t(2)\tInstall a newer-type15-5PH CRES fuse pin in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1996, or Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997. Accomplishment of this installation constitutes terminating action for the repetitive inspection requirements of paragraphs (a), (b)(1), and (c)(1) of this AD. \n\n\t(c)\tIf no corrosion or plating crack is found on the fuse pins, prior to further flight, accomplish the requirements of either paragraph (c)(1) or (c)(2) of this AD in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1998, or Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997. \n\n\t\t(1)\tInstall the existing 4330M steel fuse pins in accordance with the Accomplishment Instructions of the service bulletin. Repeat the detailed visual inspections required by paragraph (a) of this AD thereafter at intervals notto exceed 48 months. Or \n\n\t\t(2)\tInstall newer-type 15-5PH CRES fuse pins in accordance with the Accomplishment Instructions of the service bulletin. Accomplishment of this installation constitutes terminating action for the repetitive inspection requirements of paragraphs (a), (b)(1), and (c)(1) of this AD. \n\nAlternative Methods of Compliance \n\n\t(d)\tAn 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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)\tSpecial 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)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1996; or Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997. 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\n\t(g)\tThis amendment becomes effective on July 8, 1999.

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 767 series airplanes was published in the Federal Register on July 15, 1998 (63 FR 38120). That action proposed to require detailed visual inspections to detect corrosion or chrome plating cracks on the fuse pins, load distribution plates, and bushings of the outboard support of the main landing gear (MLG) beam. That action also proposed to require either installation of the existing fuse pins and repetitive inspections; or installation of newer-type fuse pins, which would constitute terminating action for 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. \n\nSupport for the Proposal \n\n\tSeveral commenters support the proposed rule.Removal of References to Bushings and Load Distribution Plates \n\n\tSeveral commenters request that all references to the bushings and load distribution plates specified in the proposal be removed. One commenter states that all references to these items have been removed in the latest revision (Revision 3) of Boeing Service Bulletin 767-57A0054. (Boeing Alert Service Bulletin 767-57A0054, Revision 2, dated April 18, 1996, was referenced in the proposal as the appropriate source of service information for accomplishment of the required actions.) Another commenter requests that the proposed inspection of the bushings and load distribution plates be removed, or if not removed, that accomplishment of the inspection, rework, and fabrication be performed in accordance with Component Maintenance Manual 57-54-23. The commenters state that the unsafe condition in the proposed AD is related to cracking of the fuse pins and is not in any way related to discrepancies of the bushings and loaddistribution plates. \n\n\tThe FAA concurs with the commenters' requests. The FAA has determined that the structural integrity of the bushings and load distribution plates is indeed not an issue, and therefore all references to the bushings and load distribution plates have been removed from the final rule. \n\n\tIn addition, the final rule has been revised to include Boeing Service Bulletin 767-57A0054, Revision 3, dated October 30, 1997, as an additional source of service information. The FAA finds that this new revision is essentially the same as Revision 2 of the alert service bulletin. However, Revision 3 removes all references to the load distribution plates and bushings described in Revision 2 of the service bulletin. \n\nRequest to Allow Class 2 Chrome Plating Finish on Fuse Pins \n\n\tOne commenter requests that the proposed rule be changed to allow a chrome plating finish requirement of Class 2 or better on the 15-5PH CRES fuse pins. The commenter states that the Class 3 plating requirement for the fuse pins is excessive because Class 2 chrome plating is an effective shield against corrosion, and the substrate of the 15-5PH CRES fuse pins is less susceptible to corrosion than the older 4330M steel fuse pins. The commenter also indicates that the requirement for Class 3 chrome plating adds an unwarranted restriction at the next overhaul. \n\n\tThe FAA does not concur with the commenter's request to allow a chrome plating finish requirement of Class 2 or better on the 15-5PH CRES fuse pins, for several reasons:\n \n\t1. As stated in the AD, the installation of the 15-5PH CRES fuse pins (with Class 3 chrome plating) is not required, but is an optional terminating action. \n\n\t2. The new 15-5PH CRES fuse pins (with Class 3 chrome plating) were selected for the configuration because they are an improvement in that they are less susceptible to corrosion than the older 4330M steel fuse pins (with Class 2 chrome plating). Considering that Class 2 chrome plating has a history of disbonding from the steel substrate, the FAA finds it practical to select an improved process (i.e., Class 3 plating) for the new, more corrosion-resistant fuse pins. \n\n\t3. The FAA reiterates that the pins called out in the service bulletin have already been manufactured with the improved Class 3 chrome plating. Compliance with this AD, and even with the optional terminating action (which is the portion of the AD that specifically calls for the installation of the 15-5PH CRES fuse pins), does not generate any excess burden on any operator by specifying that the new 15-5PH CRES fuse pins, as procured, have Class 3 chrome plating. \n\n\t4. The FAA concludes that the commenter has misinterpreted that the AD requires Class 3 chrome plating be applied to the 4330M steel fuse pins, when, in fact, the AD does not. It requires that the existing 4330M steel fuse pins (with Class 2 plating) be repetitively inspected, or, as an optional terminating action, replaced with improved 15-5PH CRES fuse pins (with Class 3 plating). \n\n\t5. Finally, in reference to the commenter's statement that Class 3 chrome plating adds an unwarranted restriction at the next overhaul, this AD does not require the existing 4330M steel fuse pins to be repaired with Class 3 plating at overhaul, nor does the AD describe any overhaul practices. Therefore, no change to the final rule is necessary in this regard. \n\nRequests to Limit Applicability \n\n\tOne commenter requests that the applicability of the proposed rule be revised to include only those airplanes with fuse pins that have been identified by the manufacturer as substandard. The commenter states that the manufacturer has been able to connect inferior batches of fuse pins provided by certain suppliers to specific airplane line positions. \n\n\tThe FAA does not concur with the commenter's request. The manufacturer has not provided the FAA with any information that connects inferior batches of fuse pins to specific airplane line positions. Without such substantiating information, the FAA has no justification to revise the applicability of the final rule. \n\n\tAnother commenter requests that the applicability of the proposed rule be revised to exclude those airplanes on which 15-5PH CRES fuse pins have already been installed. The commenter states that the installation of the newer type 15-5PH CRES fuse pins addresses the unsafe condition and, therefore, airplanes with those pins installed are not affected by the proposed rule. \n\n\tThe FAA concurs with the commenter in that installation of the new fuse pins addresses the unsafe condition as stated in the final rule. Therefore, the applicability of the final rule has been revised accordingly. \n\nRequest to Revise Cost Impact Information \n\n\tOne commenter states that the service information contains more complete information than the preamble of the proposal and reflects a more accurate statement of the actual costs of the proposal. Although no specific change was requested by the commenter, the FAA infers that the commenter wants the cost impact section of the proposed rule to be revised to reflect the time required to gain access to the area and to return the airplane to normal service. \n\n\tThe FAA does not concur. The FAA acknowledges that the cost impact information, below, describes only the "direct" costs of the specific actions required by this AD. The FAA recognizes that, in accomplishing the requirements of any AD, operators may incur "incidental" costs in addition to the "direct" costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Because incidental costs may vary significantly from operator to operator, they are almost impossible to calculate. Therefore, attempting to estimate such costs would be futile. No change to the final rule is necessary in this regard. \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 609 Boeing Model 767 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 151 airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $36,240, or $240 per airplane. \n\n\tThe cost impact figure discussed above is 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. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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 contained in 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\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: