05-24242. Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747-400, 747-400D, and 747SR Series Airplanes

AGENCY:

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

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to certain 747-100, -200, and -300 series airplanes. The existing AD currently requires repetitive inspections to detect cracking of certain lower lobe fuselage frames, and repair if necessary. This proposed AD would retain all the requirements of the existing AD, and add airplanes to the applicability. This proposed AD results from reports indicating that fatigue cracks were found in lower lobe frames on the left side of the fuselage. We are proposing this AD to detect and correct fatigue cracking of certain lower lobe fuselage frames, which could lead to fatigue cracks in the fuselage skin, and consequent rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by February 3, 2006.

ADDRESSES:

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

FOR FURTHER INFORMATION CONTACT:

Ivan Li, 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:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “Docket No. FAA-2005-23358; Directorate Identifier 2005-NM-206-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

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 proposed 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 can 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.

Discussion

On March 22, 1999, we issued AD 99-07-12, amendment 39-11097 (64 FR 15298, March 31, 1999), for certain Boeing Model 747-100, -200, and -300 series airplanes. That AD requires repetitive inspections to detect cracking of certain lower lobe fuselage frames, and repair if necessary. That AD resulted from reports indicating that fatigue cracks were found in lower lobe frames on the left side of the fuselage. We issued that AD to detect and correct fatigue cracking of certain lower lobe fuselage frames, which could lead to fatigue cracks in the fuselage skin, and consequent rapid decompression of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 99-07-12, the manufacturer has issued new service information that expands the applicability to include 747-400 and -400D series airplanes, line numbers 696 to 1152 inclusive.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2408, Revision 1, dated April 4, 2002 (the original revision of that alert service bulletin, dated April 25, 1996, was referenced as the appropriate source of service information for accomplishing the required actions in AD 99-07-12). The procedures in Revision 1 of the alert service bulletin are essentially the same as the procedures in the original revision for the airplanes affected by AD 99-07-12 (identified in the service bulletin as Group 1 airplanes). These procedures include repetitive inspections to detect cracking of certain lower lobe fuselage frames, and repair if necessary. For the 747-400 and -400D series airplanes that are added to the effectivity of the service bulletin (identified as Group 2 airplanes), the service bulletin specifies contacting the manufacturer for information about how to repair frames that have crack damage.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 99-07-12 and would retain the requirements of the existing AD. This proposed AD also would add airplanes to the applicability and require accomplishing the actions specified in the service bulletin described previously, except as discussed under “Difference Between the Proposed AD and the Service Bulletin.”

Difference Between the Proposed AD and the 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.

Explanation of Change to Applicability

We have revised the applicability of the AD to identify the model designations as published in the most recent type certificate data sheet for the affected model.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Clarification of Inspection Terminology

In this proposed AD, the “detailed visual inspection” specified in the Boeing service bulletin is referred to as a “detailed inspection.” We have also changed references to a “detailed visual inspection” in the existing AD to refer to a “detailed inspection.” We have included the definition for a detailed inspection in a note in the proposed AD.

Explanation of Change to Certain References to Other AD

AD 99-07-12 refers to AD 93-08-12 amendment 39-8559 (58 FR 27927, May 12, 1993), in the section titled “Interim Action,” and in paragraphs (a) and (d), and Note 3 of that AD. Since we issued AD 99-07-12 we have superseded AD 93-08-12 with AD 2005-20-30 amendment 39-14327 (70 FR 59252, October 12, 2005). Therefore, this proposed AD refers to AD 2005-20-30 rather than to AD 93-08-12.

Changes to Paragraph Identifiers in Existing AD

This proposed AD would retain all requirements of AD 99-07-12. Since AD 99-07-12 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requrement in AD 99-07-12	Corresponding requirement in this proposed AD
Paragraph (a)	Paragraph (f).
Paragraph (b)	Paragraph (g).
Paragraph (c)	Paragraph (h).
Paragraph (d)	Paragraph (i).

Interim Action

This is considered to be interim action only until the accomplishment of AD 2005-20-30 for Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, and 747-300, and 747SR series airplanes. AD 2005-20-30 requires a detailed inspection to detect cracks in the Section 46 lower lobe frames, and repair if necessary, in accordance with Boeing Service Bulletin 747-53-2349, Revision 2, dated April 3, 2003. The initial inspection required by AD 2005-20-30 is required prior to the accumulation of 22,000 total flight cycles. We find that earlier inspection (i.e., prior to accumulation of 15,000 total flight cycles) of the lower lobe frames is warranted, as proposed by this AD.

This is also considered to be interim action for Boeing Model 747-400 and 747-400D airplanes only until the accomplishment of an action similar to AD 2005-20-30 for these airplanes. On September 16, 2005, we issued NPRM Docket No. FAA-2005-22526 (70 FR 56860, September 29, 2005), Directorate Identifier 2005-NM-008-AD. That NPRM proposes to require repetitive inspections for cracking of certain fuselage internal structure, and repair if necessary.

Costs of Compliance

There are about 681 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 99 airplanes of U.S. registry.

The actions that are required by AD 99-07-12 and retained in this proposed AD take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of both the retained and proposed actions for U.S. operators is $12,870, or $130 per airplane, 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 have 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 that the 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed 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
• 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 Federal Aviation Administration (FAA) amends § 39.13 by removing amendment 39-11097 (64 FR 15298, March 31, 1999) and adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2005-23358; Directorate Identifier 2005-NM-206-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by February 3, 2006.

Affected ADs

(b) This AD supersedes AD 99-07-12.

Applicability

(c) This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-300, 747-400, 747-400D, and 747SR series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 747-53A2408, Revision 1, dated April 4, 2002.

Unsafe Condition

(d) This AD results from reports indicating that fatigue cracks were found in lower lobe frames on the left side of the fuselage. We are issuing this AD to detect and correct fatigue cracking of certain lower lobe fuselage frames, which could lead to fatigue cracks in the fuselage skin, and consequent rapid decompression of the airplane.

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.

Restatement of the Requirements of AD 99-07-12, With Additional Information for Group 2 Airplanes

Initial Inspections

(f) For airplanes on which the initial detailed internal inspection of the Section 46 lower lobe frames required by paragraph (f)(2) or (i)(2) of AD 2005-20-30, amendment 39-14327, has not been accomplished: Perform a detailed visual inspection to detect cracking of the lower lobe fuselage frames from Body Station 1820 to Body Station 2100, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2408, dated April 25, 1996; or Boeing Alert Service Bulletin 747-53A2408, Revision 1, dated April 4, 2002; as applicable; at the later of the applicable times specified in paragraph (f)(1), (f)(2), or (f)(3) of this AD.

(1) For all airplanes: Prior to the accumulation of 15,000 total flight cycles; or

(2) For Group 1 airplanes identified in Revision 1 of the service bulletin: Within 1,500 flight cycles or 18 months after May 5, 1999 (the effective date of AD 99-07-12), whichever occurs first.

(3) For Group 2 airplanes identified in Revision 1 of the service bulletin: Within 1,500 flight cycles or 18 months after the effective date of this AD, whichever occurs first.

Note 1:

Paragraph (f)(2) or (i)(2) of AD 2005-20-30 requires a detailed inspection to detect cracks in the Section 46 lower lobe frames, in accordance with Boeing Service Bulletin 747-53-2349, Revision 2, dated April 3, 2003. The initial inspection is required prior to the accumulation of 22,000 total flight cycles; or within 1,000 flight cycles after June 11, 1993 (the effective date of AD 93-08-12, amendment 39-8559), or November 16, 2005 (the effective date of AD 2005-20-30), depending on previous inspections accomplished; whichever occurs later.

Note 2:

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.”

Repetitive Inspections

(g) If no cracking is detected during the inspection required by paragraph (f) of this AD, repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles.

Corrective Actions

(h) If any cracking is detected during any inspection required by paragraph (f) of this AD, prior to further flight, accomplish paragraphs (h)(1) and (h)(2) of this AD:

(1) Within 20 inches of the crack location on the frame, perform a detailed inspection of the adjacent structure to detect cracking. If any cracking is detected during any detailed inspection done in accordance with paragraph (f) or (h)(1) of this AD, prior to further flight, repair in accordance with paragraph (h)(1)(i) or (h)(1)(ii) of this AD, as applicable.

(i) For Group 1 airplanes: Using a method approved in accordance with the procedures specified in paragraph (j) of this AD. The Boeing 747 Structural Repair Manual, Subject 53-10-04, Figure 67 or 90, is one approved method.

(ii) For Group 2 airplanes: Using a method approved in accordance with the procedures specified in paragraph (j) of this AD.

(2) Repeat the inspection required by paragraph (f) of this AD thereafter at intervals not to exceed 3,000 flight cycles.

Optional Terminating Inspection

(i) Accomplishment of the initial detailed inspection of the Section 46 lower lobe frames required by paragraph (f)(2) or (i)(2) of AD 2005-20-30 constitutes terminating action for the requirements of this AD only for airplanes identified in Boeing Alert Service Bulletin 747-53A2408, Revision 1, dated April 4, 2002, as Group 1 airplanes.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, 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.

(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.

(4) AMOCs approved previously in accordance with AD 99-07-12, amendment 39-11097, are approved as AMOCs for the corresponding provisions of this AD.

Issued in Renton, Washington, on December 13, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.