E8-28167. Airworthiness Directives; Boeing Model 747 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 747 airplanes. This proposed AD would require repetitive external surface high frequency eddy current inspections to detect cracks in the radius detail of the upper lobe doubler on both sides of the airplane, and applicable corrective action. This proposed AD results from reports of cracks in the radius detail of the upper lobe doublers. We are proposing this AD to detect and correct cracks in the upper lobe doublers. Such cracks could result in significant degradation of the fuselage structure and reduce its ability to carry flight loads from the vertical stabilizer, which could adversely affect the controllability of the airplane.

DATES:

We must receive comments on this proposed AD by January 12, 2009.

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:

Ivan Li, 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-2008-1239; Directorate Identifier 2008-NM-131-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 in the radius detail of the upper lobe doublers on Boeing Model 747 airplanes. The upper lobe doublers are located between the fuselage skin and vertical stabilizer attach fittings. Cracks in the upper lobe doublers, if not detected and corrected, could result in significant degradation of the fuselage structure and reduce its ability to carry flight loads from the vertical stabilizer, which could adversely affect the controllability of the airplane.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2651, dated June 12, 2008. The service bulletin describes procedures for repetitive external surface high frequency eddy current (HFEC) inspections to detect cracks in the radius detail of the upper lobe doubler on both sides of the airplane, and applicable corrective action. The corrective action involves either repairing or replacing any cracked upper lobe doubler with a new upper lobe doubler.

The compliance time for the initial external surface HFEC inspection is at the later of the following times, depending on the airplane configuration:

• Before the accumulation of 9,000 or 10,000 total flight cycles, or
• Within 48 months or 1,000 or 4,000 flight cycles, whichever occurs first.

The compliance time for the repetitive external surface HFEC inspections is within 1,500 or 4,000 flight cycles after the initial inspection, and thereafter at intervals not to exceed 1,500 or 4,000 flight cycles, depending on the airplane configuration.

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 Service Bulletin.”

Difference Between Proposed Rule and Service Bulletin

The service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions 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.

Costs of Compliance

We estimate that this proposed AD would affect 164 airplanes of U.S. registry. We also estimate that it would take about 9 work-hours per product to comply with this proposed AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be $118,080 or $720 per product, 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
• Incorporation by reference
• 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-2008-1239; Directorate Identifier 2008-NM-131-AD.

Comments Due Date

(a) We must receive comments by January 12, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2651, dated June 12, 2008.

Unsafe Condition

(d) This AD results from reports of cracks in the radius detail of the upper lobe doublers. We are issuing this AD to detect and correct cracks in the upper lobe doublers. Such cracks could result in significant degradation of the fuselage structure and reduce its ability to carry flight loads from the vertical stabilizer, which could adversely affect the controllability of the airplane.

Compliance

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

Inspection(s) and Corrective Action

(f) At the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2651, dated June 12, 2008, do repetitive external surface high frequency eddy current inspections to detect cracks in the radius detail of the upper lobe doubler on both sides of the airplane, and the applicable corrective action by accomplishing all the applicable actions specified in Accomplishment Instructions of the service bulletin, except as provided by paragraph (g) of this AD. The applicable corrective action must be done before further flight.

(g) Where Boeing Alert Service Bulletin 747-53A2651, dated June 12, 2008, specifies to contact Boeing for repair instructions instead of repairing or replacing any cracked upper lobe doubler in accordance with the service bulletin, this AD requires, before further flight, repairing any cracked upper lobe doubler using a method approved in accordance with the procedures specified in paragraph (h) of this AD.

Alternative Methods of Compliance (AMOCs)

(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, ATTN: Ivan Li, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 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, Seattle ACO, 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 November 16, 2008.

Stephen P. Boyd,

Assistant Manager, Transport Airplane Directorate, Aircraft Certification Service.