E8-10217. Airworthiness Directives; Boeing Model 707 Airplanes, and Model 720 and 720B Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. This proposed AD would require repetitive detailed inspections to detect cracks and corrosion on any existing repairs and at certain body stations of the visible surfaces of the wing to body terminal fittings including the web, flanges, and ribs; and applicable related investigative and corrective actions. This proposed AD results from reports of cracks found in the wing to body terminal fittings during routine inspections. We are proposing this AD to prevent cracks and corrosion in the body terminal fittings, which could cause loss of support for the wing and could adversely affect the structural integrity of the airplane.

DATES:

We must receive comments on this proposed AD by June 23, 2008.

ADDRESSES:

You may send comments by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Hand Delivery: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this AD, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2008-0523; Directorate Identifier 2008-NM-049-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We have received reports of cracks found in the wing to body terminal fittings during routine inspections of certain Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. The cause of the cracks has been attributed to stress corrosion. The body terminal fittings are forgings made from 7079-T6 material. Cracks and corrosion in the body terminal fittings, if not corrected, could cause loss of support for the wing and could adversely affect the structural integrity of the airplane.

Relevant Service Information

We have reviewed Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007. The service bulletin describes procedures for repetitive detailed inspections to detect cracks and corrosion on any existing repairs and at certain body stations of the visible surfaces of the wing to body terminal fittings including the web, flanges, and ribs; and applicable related investigative and corrective actions. The related investigative actions include removing the repair and doing a detailed inspection to detect cracks and corrosion of the fitting in the area covered by the repair. The corrective action includes contacting Boeing for repair instructions.

FAA's Determination and Requirements of this Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the(se) same type design(s). This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Difference Between the Proposed AD and Referenced Service Bulletin.”

Difference Between the Proposed AD and Referenced Service Bulletin

Operators should note that, although the Accomplishment Instructions of the referenced Boeing service bulletin describe procedures for submitting information to the manufacturer, this proposed AD would not require that action.

Costs of Compliance

Estimated Costs

Action	Work hours	Average labor rate per hour	Cost per product	Number of U.S.-registered airplanes	Fleet cost
Inspections	20	$80	$1,600, per inspection cycle	5	$8,000 per inspection cycle.

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 determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 FAA amends § 39.13 by adding the following new AD:

Boeing: Docket No. FAA-2008-0523; Directorate Identifier 2008-NM-049-AD.

Comments Due Date

(a) We must receive comments by June 23, 2008.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; Model 707-300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes, certificated in any category; as identified in Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007.

Unsafe Condition

(d) This AD results from reports of cracks found in the wing to body terminal fittings during routine inspections. We are issuing this AD to prevent cracks and corrosion in the body terminal fittings, which could cause loss of support for the wing and could adversely affect the structural integrity of the airplane.

Compliance

(e) Comply with this AD within the compliance times specified, unless already done.

Inspections and Corrective Actions

(f) Within 24 months after the effective date of this AD, do detailed inspections and applicable related investigative and corrective actions, by accomplishing all the actions specified in the Accomplishment Instructions of Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007, except as provided by paragraph (g) of this AD. Repeat the detailed inspections thereafter at intervals not to exceed 24 months. Do all applicable related investigative and corrective actions before further flight.

(g) If any crack or corrosion is found during any inspection required by paragraph (f) of this AD, and Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007, specifies to contact Boeing for appropriate action: Before further flight, repair the terminal fittings using a method approved in accordance with the procedures specified in paragraph (i) of this AD.

No Information Submission

(h) Although Boeing 707 Special Attention Service Bulletin 3524, dated July 18, 2007, specifies to submit information to the manufacturer, this AD does not include that requirement.

Alternative Methods of Compliance (AMOCs)

(i)(1) The Manager, Seattle Aircraft Certification Office (SACO), FAA, ATTN: Berhane Alazar, Aerospace Engineer, Airframe Branch, ANM-120S, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]; has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, SACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

Issued in Renton, Washington, on April 25, 2008.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.