AD 2004-07-06

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 707 and 720 series airplanes, that requires repetitive inspections of the upper and lower barrel nuts and bolts that retain the aft trunnion support fitting of each main landing gear for corrosion, cracks, and loose or missing nuts and bolts; torque checks of the upper and lower bolts to verify the torque is within a specified range; and corrective actions, if necessary. This action is necessary to detect and correct cracking and/or loss of the barrel nuts and bolts that retain the aft trunnion support fitting, which could result in the collapse of the main landing gear upon landing. This action is intended to address the identified unsafe condition.

Final rule.

2004-07-06 Boeing: Amendment 39-13550. Docket 2002-NM-335-AD. \n\n\tApplicability: Model 707 and 720 series airplanes, as listed in Boeing 707 Alert Service Bulletin A3509, dated June 13, 2002; certificated in any category.\n \n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct cracking and/or loss of the upper and lower barrel nuts and bolts that retain the aft trunnion support fitting, which could result in the collapse of the main landing gear upon landing, accomplish the following: \n\nService Bulletin References \n\n\t(a) The term "service bulletin," as used in this AD, means the Accomplishment Instructions of Boeing 707 Alert Service Bulletin A3509, dated June 13, 2002. \n\nInitial Inspection \n\n\t(b) Within 60 days after the effective date of this AD, for each main landing gear, perform the inspection specified in paragraph (b)(1) of this AD and the torque check specified in paragraph (b)(2) of this AD, in accordance with the service bulletin. \n\n\t(1) Perform a detailed inspection of the upper and lower barrel nuts and bolts that retain the aft trunnion support fitting for corrosion, cracks, and loose or missing nuts and bolts. \n\n\t(2) Torque check the upper and lower bolts to verify the torque is within the range specified in Figure 2 of the service bulletin. \n\nRepetitive Inspections \n\n\t(c) If no corrosion, crack, or loose or missing nut or bolt is found, and the torque is found to be within the specified range, during the inspection and torque check specified in paragraph (b) of this AD, then repeat the actions specified in paragraph (b) of this AD thereafter at intervals not to exceed 60 days. \n\nCorrective Actions \n\n\t(d) If any corrosion, crack, or loose or missing nut or bolt is found, or if the torque is found not to be within the specified range, during the inspection and torque check specified in paragraph (b) of this AD: Before further flight, do the corrective actions specified in paragraphs (d)(1) through (d)(3) of this AD. Accomplishment of these actions constitutes terminating action for the repetitive inspections specified in paragraph (c) of this AD. \n\n\t(1) Perform a detailed inspection of the aft trunnion bearing cap and aft trunnion support fitting for corrosion, in accordance with the service bulletin. If any corrosion is detected, before further flight, repair in accordance with the service bulletin.\n \n\t(2) Perform a magnetic particle inspection of the aft trunnion bearing cap for cracks in accordance with Figure 3 of the service bulletin. \n\n\t(i) If no crack is found, before further flight, reinstall the inspected aft trunnion bearing cap in accordance with the service bulletin.\n \n\t(ii) If any crack is found, before further flight, replace the aft trunnion bearing cap with a new aft trunnion bearing cap in accordance with the service bulletin. \n\n\t(3) Reinstall the main landing gear trunnion with new Inconel barrel nuts and bolts to retain the aft trunnion support fitting, in accordance with Figure 4 of the service bulletin. \n\nTerminating Action \n\n\t(e) Within one year after the effective date of this AD, for each main landing gear, replace the upper and lower steel barrel nuts and H-11 bolts that retain the aft trunnion support fitting with new Inconel barrel nuts and bolts as specified in paragraphs (d)(1) through (d)(3) of this AD. Accomplishment of these actions constitutes terminating action for the requirements of this AD. \n\nParts Installation \n\n\t(f) As of the effective date of this AD, no person shall install a steel barrel nut with H-11 bolt to retain the aft trunnion support fitting, on any airplane. \n\nAlternative Methods of Compliance \n\n\t(g) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance for this AD. \n\nIncorporation by Reference \n\n\t(h) The actions shall be done in accordance with Boeing 707 Alert Service Bulletin A3509, dated June 13, 2002. 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 Airplanes, 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(i) This amendment becomes effective on May 11, 2004.

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 707 and 720 series airplanes was published in the Federal Register on December 18, 2003 (68 FR 70477). That action proposed to require repetitive inspections of the upper and lower barrel nuts and bolts that retain the aft trunnion support fitting of each main landing gear for corrosion, cracks, and loose or missing nuts and bolts; torque checks of the upper and lower bolts to verify the torque is within a specified range; and corrective actions, if necessary. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. We received no comments on the proposal or on the determination of the cost to the public. \n\nConclusion \n\n\tAfter careful review of the available data, we have determined that air safety and the public interest requirethe adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 230 airplanes of the affected design in the worldwide fleet. The FAA estimates that 42 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 required detailed inspection of the upper and lower barrel nuts and bolts and the torque check. The average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $2,730, or $65 per airplane, per inspection and torque check. \n\n\tIt will take approximately 3 work hours per airplane to accomplish the required detailed inspection of the aft trunnion bearing cap. The average labor rate is $65 per airplane. Based on these figures, the cost impact on U.S. operators is estimated to be $8,190, or $195 per airplane. \n\n\tIt will take approximately 4 work hours per airplane to accomplish the required installation of the new Inconel barrel nut and bolt and the main landing gear trunnion. The average labor rate is $65 per work hour. Based on these figures, the cost on U.S. operators is estimated to be $10,920, or $260 per airplane. \n\n\tRequired parts will cost approximately $3,380 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 nationalGovernment 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 \nExecutive 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. \nAdoption ofthe Amendment \n\nAccordingly, 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\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. Section 39.13 is amended by adding the following new airworthiness directive: