Airworthiness Directives; Boeing Model 747 Series Airplanes

AGENCY:

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

ACTION:

Final rule; request for comments.

SUMMARY:

The FAA is superseding an existing airworthiness directive (AD) that applies to all Boeing Model 747 series airplanes. The existing AD currently requires repetitive inspections for cracking of the top and side panel webs and panel stiffeners of the nose wheel well (NWW), and corrective actions if necessary. This new AD expands the area of inspection, adds a new “secondary” inspection if certain cracking is found, and reduces the intervals for the repetitive inspections. This AD is prompted by a report of an in-flight decompression of a Model 747-100 series airplane that had accumulated 27,241 total flight cycles. We are issuing this AD to detect and correct fatigue cracks in the top and side panel webs and stiffeners of the NWW, which could compromise the structural integrity of the NWW and could lead to the rapid decompression of the airplane.

DATES:

Effective May 10, 2005.

The incorporation by reference of Boeing Alert Service Bulletin 747-53A2465, Revision 4, dated February 24, 2005, as listed in the AD, is approved by the Director of the Federal Register as of May 10, 2005.

On January 27, 2005 (69 FR 76839, December 23, 2004), the Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003; and Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004.

We must receive any comments on this AD by June 24, 2005.

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: (202) 493-2251.
• 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.

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

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-21027; the directorate identifier for this docket is 2005-NM-048-AD.

Examining the Docket

You can 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 (800) 647-5227) 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 DMS receives them.

FOR FURTHER INFORMATION CONTACT:

Nick Kusz, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6432; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

On December 7, 2004, we issued AD 2004-25-23, amendment 39-13911 (69 FR 76839, December 23, 2004). That AD applies to all Boeing Model 747 series airplanes. That AD requires repetitive inspections for cracking of the top and side panel webs and panel stiffeners of the nose wheel well (NWW), and corrective actions if necessary. That AD was prompted by reports indicating that cracks have been found on the top and side panel webs and side panel horizontal stiffeners of the NWW on Boeing Model 747 series airplanes. Investigation revealed that the cracking was due to fatigue. The actions specified in that AD are intended to detect and correct fatigue cracks in the top and side panel webs and stiffeners of the NWW, which could compromise the structural integrity of the NWW and could lead to the rapid decompression of the airplane.

Actions Since AD Was Issued

Since we issued that AD, the FAA has received a report of an in-flight decompression on a Boeing Model 747-100 series airplane. The airplane landed safely, and investigation revealed that the right-hand side panel web of the NWW was torn open between station (STA) 260 and STA 280, and from water line (WL) 160 to WL 170. The decompression also caused damage to the nose landing gear doors and adjacent structure.

Relevant Service Information

We have reviewed Boeing Alert Service Bulletin (ASB) 747-53A2465, Revision 4, dated February 24, 2005. The ASB describes procedures for performing repetitive external detailed and ultrasonic inspections for cracking of the top and side panel webs (Areas 1 and 2) of the NWW and for performing repetitive internal detailed and surface high frequency eddy current inspections (Area 3) for cracking of the top and side panel stiffeners of the NWW; replacing cracked stiffeners with new stiffeners; and repairing any cracked panel web. Revision 4 of the ASB also describes detailed “secondary inspections” for certain cracking found and specifies contacting Boeing for further action if other cracking is found. Revision 4 of the ASB describes procedures for expanding the area of inspection of the web from STA 260 to STA 270 along WL 140. Revision 4 of the ASB also specifies reducing the repetitive inspection intervals for Area 1 and Area 2 and includes additional repetitive detailed and ultrasonic (UT) inspections. Revision 4 of the ASB also describes reducing the repetitive inspection intervals for the inspections of Area 3.

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. This AD is being issued to supersede AD 2004-25-23. This new AD continues to require repetitive inspections for cracking of the top and side panel webs and panel stiffeners of the NWW, and corrective actions if necessary. This AD expands the area of inspection, adds a new “secondary” inspection if certain cracking is found, and reduces the repetitive inspection intervals.

Differences Between the AD and Revision 4 of the ASB

Although the ASB specifies that operators may contact the manufacturer for disposition of certain repair conditions, this AD requires operators to repair those conditions according to a method approved by the FAA. Although the ASB specifies certain initial inspection compliance times relative to January 27, 2005 (the effective date of AD 2004-25-23), this AD requires those certain initial inspection compliance times in relation to the effective date of this AD. While the ASB describes reducing the current repetitive inspection intervals for Area 3 from 6,000 flight cycles to 1,500 flight cycles, this AD does not require the reduced intervals. Requiring the repetitive intervals at 1,500 flight cycles would allow adequate time for public opportunity to comment, and we would issue a proposed AD to provide that comment period. Therefore, we may consider further rulemaking to address this issue. In addition, the ASB specifies that operators should report inspection results to the manufacturer, but this AD does not require those inspection results to be reported.

Change to Existing AD

This AD would retain certain requirements of AD 2004-25-23. Since AD 2004-25-23 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 AD, as listed in the following table:

Interim Action

This is considered to be interim action. As previously discussed, we may consider further rulemaking regarding reducing certain repetitive inspection intervals. In addition, the manufacturer has advised that it currently is developing a modification that will address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and 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 under ADDRESSES. Include “Docket No. FAA-2005-21027; Directorate Identifier 2005-NM-048-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the 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 AD. Using the search function of our docket 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 can 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.

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. 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 part 39 of the Federal Aviation Regulations (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.

2. The FAA amends § 39.13 by removing amendment 39-13911 ( 69 FR 76839, December 23, 2004), and adding the following new airworthiness directive (AD):

2005-09-02 Boeing: Docket No. FAA-2005-21027; Directorate Identifier 2005-NM-048-AD; Amendment 39-14070.

Effective Date

(a) This AD becomes effective May 10, 2005.

Affected ADs

(b) This AD supersedes AD 2004-25-23, amendment 39-13911 (69 FR 76839, December 23, 2004).

Applicability

(c) This AD applies to all Boeing Model 747 series airplanes, certificated in any category.

Unsafe Condition

(d) This AD was prompted by a report of an in-flight decompression of a Model 747-100 series airplane that had accumulated 27,241 total flight cycles. We are issuing this AD to detect and correct fatigue cracks in the top and side panel webs and stiffeners of the Nose Wheel Well (NWW), which could compromise the structural integrity of the NWW and could lead to the 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 2004-25-23

Initial and Repetitive Inspections

(f) Prior to the accumulation of 16,000 total flight cycles, or within 1,000 flight cycles after January 27, 2005 (the effective date of AD 2004-25-23), whichever is later, do the inspections specified in either paragraph (f)(1) or (f)(2) of this AD.

(1) Do the inspections specified in paragraphs (f)(1)(i) and (f)(1)(ii) of this AD in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles.

(i) Do detailed and ultrasonic inspections of the top and side panel webs of the NWW for cracks.

(ii) Do detailed and surface high frequency eddy current (HFEC) inspections of the top and side panel stiffeners of the NWW for cracks.

(2) Do the inspections specified in paragraphs (f)(2)(i) and (f)(2)(ii) of this AD in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004. Repeat the inspections thereafter at the intervals specified in paragraphs (f)(2)(i) and (f)(2)(ii) of this AD.

(i) Do external detailed inspections of the top and side panel webs of the NWW (specified as Area 1 and Area 2 in the service bulletin), as applicable, for cracks. Repeat the inspections thereafter at intervals not to exceed 1,000 flight cycles.

(ii) Do internal detailed and surface HFEC inspections of the top and side panel stiffeners of the NWW (specified as Area 3 in the service bulletin) for cracks. Repeat the inspections thereafter at intervals not to exceed 6,000 flight cycles.

Note 1:

For the purposes of this AD, a detailed inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirrors, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

New Requirements of This AD

(g) Do an external detailed inspection of the top and sidewall panel webs of the NWW (specified as Area 1 and Area 2 in the service bulletin) for cracks, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin (ASB) 747-53A2465, Revision 4, dated February 24, 2005, at the earlier of the times specified in paragraphs (g)(1) and (g)(2) of this AD. Accomplishment of this inspection terminates the requirements for the inspections specified in paragraphs (f)(1)(i) and (f)(2)(i) of this AD.

(1) At the later of the times specified in paragraph (g)(1)(i) and (g)(1)(ii) of this AD:

(i) Before accumulating 20,000 total flight cycles.

(ii) Within 100 flight cycles or 90 days after the effective date of this AD, whichever occurs first.

(2) At the later of the times specified in paragraphs (g)(2)(i) and (g)(2)(ii) of this AD:

(i) Before accumulating 16,000 total flight cycles.

(ii) Within 1,000 flight cycles after the effective date of this AD.

Repetitive Inspections

(h) Repeat the inspection required by paragraph (g) of this AD at the intervals specified in paragraph (h)(1) or (h)(2) of this AD, as applicable.

(1) For airplanes with less than 20,000 total flight cycles as of the effective date of this AD, repeat at intervals not to exceed 1,000 flight cycles until the first inspection after the airplane reaches 20,000 total flight cycles.

(2) For airplanes with 20,000 total flight cycles or more, repeat at intervals not to exceed 500 flight cycles.

Ultrasonic Inspections (UT)

(i) Do a UT inspection of the sidewall panel web for cracks, in accordance with Boeing ASB 747-53A2465, Revision 4, dated February 24, 2005, at the later of the times specified in paragraphs (i)(1) and (i)(2) of this AD. Repeat the inspections thereafter at intervals not to exceed 500 flight cycles.

(1) Prior to the accumulation of 20,000 total flight cycles.

(2) Within 100 flight cycles or within 90 days after the effective date of this AD, whichever occurs first.

Additional Inspections and Corrective Actions

(j) Except as specified in paragraph (l) of this AD, if any crack is found during any inspection required by this AD, prior to further flight, do any applicable additional detailed inspections of stiffeners and beams and make repairs, in accordance with the Accomplishment Instructions of Boeing ASB 747-53A2465, Revision 4, dated February 24, 2005.

Actions Accomplished per Previous Issues of Service Bulletin

(k) Inspections and corrective actions accomplished before January 27, 2005, in accordance with Boeing ASB 747-53A2465, dated April 5, 2001, are considered acceptable for compliance with the corresponding inspections specified in paragraph (f) of this AD. Inspections and corrective actions accomplished before the effective date of this AD, in accordance with Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003; Revision 2, dated November 11, 2004; and Revision 3, dated December 23, 2004; are considered acceptable for compliance with the corresponding inspections specified in paragraphs (g) and (h) of this AD.

Certain Other Corrective Actions

(l) Where the ASB specifies contacting the manufacturer if certain cracking is found, this AD requires repairing the cracking according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or by an Authorized Representative for the Boeing Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. The repair must be accomplished before further flight. 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.

No Reporting Requirements

(m) Although the Boeing ASB specifies that operators should report inspection results to the manufacturer, this AD does not require those inspection results to be reported.

Alternative Methods of Compliance (AMOCs)

(n)(1) The Manager, Seattle 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) 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 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.

Material Incorporated by Reference

(o) You must use Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003; Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004; and Boeing Alert Service Bulletin 747-53A2465, Revision 4, dated February 24, 2005; as applicable, to perform the actions that are required by this AD, unless the AD specifies otherwise.

(1) The incorporation by reference of Boeing Alert Service Bulletin 747-53A2465, Revision 4, dated February 24, 2005, is approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) The incorporation by reference of Boeing Service Bulletin 747-53A2465, Revision 1, dated October 16, 2003; and Boeing Alert Service Bulletin 747-53A2465, Revision 2, dated November 11, 2004; was approved previously by the Director of the Federal Register as of January 27, 2005 (69 FR 76839, December 23, 2004).

(3) To get copies of the service information, contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. To view the AD docket, go to the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, Nassif Building, Washington, DC. To review copies of the service information, go to the National Archives and Records Administration (NARA). For information on the availability of this material at the NARA, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.