06-2545. Airworthiness Directives; Boeing Model 720 and 720B Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 720 and 720B series airplanes. This AD requires repetitive inspections for any crack, corrosion, or sign of damage (e.g., finish scratches, blistering, or signs of fuel leaking) of the front spar upper chords under the fairing web, and repair if necessary. This AD results from a report that inspections required by a previous AD action are inadequate for Boeing Model 720 and 720B series airplanes. We are issuing this AD to detect and correct any crack, corrosion, or sign of damage of the front spar upper chords under the fairing web, which could result in structural failure of the wing.

DATES:

This AD becomes effective April 3, 2006.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of April 3, 2006.

We must receive comments on this AD by May 16, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility; U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in This AD.

FOR FURTHER INFORMATION CONTACT:

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

SUPPLEMENTARY INFORMATION:

Discussion

We previously issued AD 2004-22-24, amendment 39-13852 (69 FR 64835, November 9, 2004), for all Boeing Model 707 and 720 series airplanes. That AD requires repetitive detailed and high frequency eddy current inspections for corrosion, signs of corrosion (e.g., blistering or signs of fuel leaks), and cracking, and certain related follow-on and investigative actions if necessary. That AD resulted from a report of a 31-inch crack found during a routine inspection. We issued that AD to find and fix corrosion and stress corrosion cracking of the upper and lower chords on the wing front and rear spars, which could result in reduced structural integrity of the wing.

Since we issued that AD, Boeing has informed us that, for Model 720 and 720B series airplanes, the repetitive inspections required by AD 2004-22-24 do not adequately address the identified unsafe condition. The wing configuration of Model 720 and 720B series airplanes differs from that on Model 707 series airplanes. Model 720 series airplanes have an aerodynamic fairing that extends from the aircraft side of body to the inboard nacelle. This fairing prevents operators from doing the repetitive inspections intended by AD 2004-22-24. Cracks, corrosion, or signs of damage (e.g., finish scratches, blistering or signs of fuel leaking) of the front spar upper chords under the fairing web, if not detected and corrected, could result in structural failure of the wing.

Relevant Service Information

We have reviewed Boeing Multi-Operator Message (MOM) 1-151636045-1, dated January 17, 2006. The MOM describes procedures for doing repetitive detailed and high-frequency eddy current (HFEC) inspections for any crack, corrosion, or scratch of the front spar upper chords under the fairing web, and repair if necessary. The HFEC inspection is in the area of the forward face of the vertical flange, from the side of the body to the inboard nacelle (front spar station 107 through 383), from the upper fastener row to the upper edge of the chord flange, and the surface in between. The detailed inspection is of the forward face of the vertical flange from the upper edge of the chord flange to the lower edge of the chord flange. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of This AD

The unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to detect and correct any crack, corrosion, or sign damage (e.g., finish scratches, blistering, or signs of fuel leaking) of the front spar upper chords under the fairing web, which could result in structural failure of the wing. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the AD and the MOM.”

Differences Between the AD and the MOM

Although the MOM specifies to contact the manufacturer for repair instructions, this proposed AD would require operators to do the repair using a method we approve.

The MOM also specifies to contact the manufacturer for instructions on oversizing fasteners during restoration, but this proposed AD would require oversizing the fasteners in one of the following ways:

• Using a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings.

FAA's Determination of the Effective Date

Since an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days.

Comments Invited

This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include “Docket No. FAA-2006-24162; Directorate Identifier 2006-NM-031-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.

We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD 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.

For the reasons discussed above, I certify that the regulation:

1. Is not a “significant regulatory action” under Executive Order 12866;

2. Is not a “significant rule” under the 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.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

2006-06-05 Boeing: Amendment 39-14513. Docket No. FAA-2006-24162; Directorate Identifier 2006-NM-031-AD.

Effective Date

(a) This AD becomes effective April 3, 2006.

Affected ADs

(b) Accomplishing the inspections in paragraph (f) of this AD terminates the repetitive inspection requirements of paragraph (c) of AD 2004-22-24, amendment 39-13852, for the front spar upper chord stations 107 through 383 only, for Boeing Model 720 and 720B series airplanes only.

Applicability

(c) This AD applies to all Boeing Model 720 and 720B series airplanes, certificated in any category.

Unsafe Condition

(d) This AD results from a report that inspections required by previous AD action are inadequate for Boeing Model 720 and 720B series airplanes. We are issuing this AD to detect and correct any crack, corrosion, or sign of damage (e.g., finish scratches, blistering, or signs of fuel leaking) of the front spar upper chords under the fairing web, which could result in structural failure of the wing.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Repetitive Inspections

(f) Within 30 days after the effective date of this AD: Do detailed and high-frequency eddy current (HFEC) inspections for any crack, corrosion, or sign of damage (e.g., finish scratches, blistering, or signs of fuel leaking) of the front spar upper chords under the fairing web; and repair if necessary; by accomplishing all the actions specified in Boeing Multi-Operator Message (MOM) 1-151636045-1, dated January 17, 2006. If any crack, corrosion, or sign of damage is found, do all applicable repairs before further flight. Repeat the inspections thereafter at intervals not to exceed 12 months. Where the MOM specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.

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.”

Instructions for Oversizing Fasteners

(g) Where Boeing MOM 1-151636045-1, dated January 17, 2006, specifies to contact Boeing for appropriate action if it is necessary to oversize fasteners during restoration: Before further flight, oversize the fasteners using a method approved in accordance with a method approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Material Incorporated by Reference

(i) You must use Boeing Multi-Operator Message (MOM) 1-151636045-1, dated January 17, 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, Nassif Building, Washington, DC; on the Internet at http://dms.dot.gov ; or at the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call [phone], or go to http://www.archives.gov/​federal_​register/​code_​of_​federal_​regulations/​ibr_​locations.html .

Issued in Renton, Washington, on March 7, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.