04-4684. Airworthiness Directives; Boeing Model 707 and 720 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to all Boeing Model 707 and 720 series airplanes, that requires inspection of the bolt forward of the wing front spar upper chord on the overwing support fittings of the inboard and outboard nacelle struts to verify that BACB30US type bolts are installed. If any other type of bolt is found, this amendment requires replacement with a new BACB30US type bolt. This action is necessary to prevent separation of the engine from the airplane due to stress corrosion cracking and consequent fracturing of the bolts. This action is intended to address the identified unsafe condition.

DATES:

Effective April 14, 2004.

The incorporation by reference of a certain publication listed in the regulations is approved by the Director of the Federal Register as of April 14, 2004.

ADDRESSES:

The service information referenced in this AD may be obtained from Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Candice Gerretsen, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

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 all Boeing Model 707 and 720 series airplanes was published in the Federal Register on November 25, 2003 (68 FR 66028). That action proposed to require inspection of the bolt forward of the wing front spar upper chord on the overwing support fittings of the inboard and outboard nacelle struts to verify that BACB30US type bolts are installed. If any other type of bolt is found, that action proposed to require replacement with a new BACB30US type bolt.

Comments

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

Conclusion

The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.

Cost Impact

There 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, that it will take approximately 1 work hour per airplane to accomplish the required inspection, and that 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.

The 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. 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.

Regulatory Impact

The 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.

For 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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, 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:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2004-05-14 Boeing: Amendment 39-13509. Docket 2002-NM-334-AD.

Applicability: All Model 707 and 720 series airplanes, as listed in Boeing 707/720 Alert Service Bulletin A3502, dated February 21, 2002; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent separation of the engine from the airplane due to stress corrosion cracking and consequent fracturing of the bolts, accomplish the following:

Service Bulletin References

(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing 707/720 Alert Service Bulletin A3502, dated February 21, 2002.

Inspection and Corrective Action

(b) Except as provided by paragraph (c) of this AD, within 12 months from the effective date of this AD, perform a general visual inspection of the bolts forward of the wing front spar upper chord on the overwing support fittings of the inboard and outboard nacelle struts to verify that BACB30US type bolts are installed, per Figure 1 of the service bulletin.

Note 1:

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.”

(c) The service bulletin specifies that reviewing records is another way to verify if a BACB30US type bolt is installed. However, this AD does not allow that alternative. The general visual inspection required by paragraph (b) of this AD must be accomplished to verify if BACB30US type bolts are installed.

(d) If any bolt other than the BACB30US type bolts specified in Figure 1 of the service bulletin is found during the inspection required by paragraph (b) of this AD or if any bolt cannot be identified: Prior to further flight, do the actions specified in paragraphs (d)(1) and (d)(2) of this AD, per Figure 2 of the service bulletin.

(1) Perform a high frequency eddy current (HFEC) inspection of the hole bore for cracks and corrosion and measure the hole to verify the diameter is within the specified dimensions. If any corrosion or cracking is found or if the measured hole diameter is not within the specified dimensions, and the service bulletin specifies to contact Boeing for appropriate action: Prior to further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved, the approval must specifically reference this AD.

(2) Replace the bolt with a new BACB30US type bolt per Figure 2 of the service bulletin.

Parts Installation

(e) As of the effective date of this AD, no person shall install any bolt other than a BACB30US type bolt in the locations specified in this AD, on any airplane.

Alternative Methods of Compliance

(f) 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.

Incorporation by Reference

(g) Unless otherwise specified in this AD, the actions shall be done in accordance with Boeing 707/720 Alert Service Bulletin A3502, dated February 21, 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.

Effective Date

(h) This amendment becomes effective on April 14, 2004.

Issued in Renton, Washington, on February 24, 2004.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.