E7-16121. Airworthiness Directives; Boeing Model 747 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 Boeing Model 747-200B, 747-200C, 747-200F, 747-300, 747-400, and 747SP series airplanes. The existing AD currently requires doing a detailed inspection of the left and right longeron extension fittings, and corrective action if necessary. This proposed AD would add airplanes to the applicability of the existing AD. This proposed AD results from reports that accidental drilling damage to the longeron extension fittings was found on airplanes not subject to the existing AD. We are proposing this AD to detect and correct accidental drilling damage of the longeron extension fittings, which could lead to cracking of the longeron extension fittings and result in rapid decompression of the airplane.

DATES:

We must receive comments on this proposed AD by October 1, 2007.

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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590.
• Fax: [phone].
• Hand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., 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 98057-3356; 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-2007-28989; Directorate Identifier 2007-NM-070-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 may 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 Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone [phone]) is located on the ground floor of the West 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 April 28, 2006, we issued AD 2006-10-04, amendment 39-14588 (71 FR 27592, May 12, 2006), for certain Boeing Model 747-200B, 747-200C, 747-200F, 747-300, 747-400, and 747SP series airplanes. That AD requires doing a detailed inspection of the left and right longeron extension fittings, and corrective action if necessary. That AD resulted from cracking found in the longeron extension fitting at body station 1480 due to accidental damage during production. We issued that AD to detect and correct cracking in the longeron extension fitting, which could result in rapid decompression of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2006-10-04, we received reports that accidental drill damage was discovered during inspections of the longeron extension fittings of five airplanes not subject to that AD, including one airplane manufactured before the airplanes specified in the effectivity of Boeing Alert Service Bulletin 747-53A2515, dated October 20, 2005 (cited in AD 2006-10-04 as the appropriate source of service information). Boeing therefore concluded that additional airplanes which might be subject to the unsafe condition should be added to the effectivity of a revision of that service bulletin.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin 747-53A2515, Revision 1, dated March 1, 2007. Revision 1 of the alert service bulletin is essentially the same as the original issue, except that airplanes have been added to its effectivity.

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 2006-10-04 and would retain certain requirements of the existing AD. The proposed AD would also add airplanes to the applicability of the existing AD. The proposed AD would remove the reporting requirement of the existing AD. The proposed AD would also require accomplishing the actions specified in the service information 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.

Interim Action

We consider this proposed AD interim action. If final action is later identified, we may consider further rulemaking then.

Costs of Compliance

There are about 876 airplanes of the affected design in the worldwide fleet. This proposed AD would affect about 156 airplanes of U.S. registry.

The actions specified by this proposed AD were previously required by AD 2006-10-04, which was applicable to approximately 25 airplanes of U.S. registry. The actions required by that AD take about 1 work hour per airplane. We estimated the cost of the current requirements of that AD on U.S. operators to be $2,000, or $80 per airplane. Some operators of the 25 airplanes subject to AD 2006-10-04 may have already initiated the required actions. This proposed AD would add no new costs associated with those airplanes.

This proposed AD would be applicable to approximately 131 additional airplanes of U.S. registry. New actions required by this proposed AD would take about 1 work hour per airplane. Based on the current labor rate of $80 per work hour, we estimate the new costs imposed by this proposed AD on U.S. operators to be $10,480, or $80 per airplane. This figure is based on assumptions that no operator of these additional airplanes has yet done any of the proposed requirements of this AD, and that no operator would do those actions in the future if this AD were not adopted.

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 39-14588 (71 FR 27592, May 12, 2006) and adding the following new airworthiness directive (AD):

BOEING: Docket No. FAA-2007-28989; Directorate Identifier 2007-NM-070-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by October 1, 2007.

Affected ADs

(b) This AD supersedes AD 2006-10-04.

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 747-53A2515, Revision 1, dated March 1, 2007.

Unsafe Condition

(d) This AD results from reports that accidental drilling damage to the longeron extension fittings was found on airplanes not subject to the existing AD. We are issuing this AD to detect and correct accidental drilling damage of the longeron extension fittings, which could lead to cracking of the longeron extension fittings and result in 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 Certain Requirements of AD 2006-10-04

Detailed Inspection

(f) For Group 1 airplanes identified in Boeing Alert Service Bulletin 747-53A2515, Revision 1, dated March 1, 2007: At the applicable compliance time specified in paragraph (f)(1) or (f)(2) of this AD, do a detailed inspection of the left and right longeron extension fittings for damage, and, before further flight, do the corrective action if applicable, by accomplishing all the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2515, dated October 20, 2005; or Revision 1, dated March 1, 2007.

Note 1:

Boeing Alert Service Bulletin 747-53A2515, dated October 20, 2005; and Revision 1, dated March 1, 2007; refer to Boeing Alert Service Bulletin 747-53A2390, Revision 1, dated July 6, 2000, as an additional source of service information for replacing a damaged longeron fitting with a new longeron extension fitting.

(1) For airplanes that have accomplished the inspection of the splice area for cracking as specified in Boeing Alert Service Bulletin 747-53A2390, dated July 31, 1997; or Revision 1, dated July 6, 2000: Inspect in accordance with paragraph (f) of this AD before the airplane has accumulated 10,000 total flight cycles, or within 1,000 flight cycles after June 16, 2006 (the effective date of AD 2006-10-04), whichever is later.

(2) For airplanes that have not accomplished the inspection of the splice area for cracking as specified in Boeing Alert Service Bulletin 747-53A2390, dated July 31, 1997; or Revision 1, dated July 6, 2000: Inspect in accordance with paragraph (f) of this AD before the airplane has accumulated 10,000 total flight cycles, or within 250 flight cycles after June 16, 2006, whichever is later.

New Requirements of This AD

Detailed Inspection of Additional Airplanes

(g) For Group 2 and Group 3 airplanes identified in Boeing Alert Service Bulletin 747-53A2515, Revision 1, dated March 1, 2007: Except as provided by paragraphs (h) and (i) of this AD, at the applicable time specified in paragraph 1.E of Boeing Alert Service Bulletin 747-53A2515, Revision 1, dated March 1, 2007, do a detailed inspection of the left and right longeron extension fittings for damage and, before further flight, do the corrective action, as applicable; by accomplishing all the applicable actions specified in the Accomplishment Instructions of the alert service bulletin.

Compliance Times

(h) Where the alert service bulletin specifies compliance times relative to the release date of the alert service bulletin, this AD requires compliance at compliance times relative to the effective date of this AD.

Repair of Certain Conditions

(i) If any damage is found during any inspection required by this AD and the service bulletin specifies to contact Boeing for appropriate action: Before further flight, repair the damage using a method approved in accordance with the procedures specified in paragraph (k) of this AD.

Credit for Actions Done Using Previous Service Information

(j) Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-53A2515, dated October 20, 2005, are considered acceptable for compliance with the corresponding actions of this AD.

Alternative Methods of Compliance (AMOCs)

(k)(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) AMOCs approved previously in accordance with AD 2006-10-04, are approved as AMOCs for the corresponding provisions of this AD.

(3) 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.

(4) 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 July 30, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.