Federal Aviation Administration, DOT.
Notice of proposed rulemaking (NPRM).
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747-400F series airplanes. This proposal would require repetitive detailed and general visual inspections of the external fuselage skin for cracks; various inspections of the affected area where cracks are found to determine the extent of the damage; and repair of cracks. This action is necessary to detect and correct fatigue cracks in the fuselage skin and frame shear tie assemblies, which could propagate and result in possible in-flight decompression of the airplane. This action is intended to address the identified unsafe condition.
Comments must be received by January 12, 2004.
Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-288-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9 a.m. and 3 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to (425) 227-1232. Comments may also be sent via the Internet using the following address: firstname.lastname@example.org. Comments sent via fax or the Internet must contain “Docket No. 2002-NM-288-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 or 2000 or ASCII text.
The service information referenced in the proposed rule may be obtained from Boeing Commercial Airplane Group, PO Box 3707, Seattle, Washington 98124-2207. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.Start Further Info
FOR FURTHER INFORMATION CONTACT:
Candice Gerretsen, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 917-6428; fax (425) 917-6590.End Further Info End Preamble Start Supplemental Information
Interested persons are invited to participate in the making of the proposed rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.
Submit comments using the following format:
- Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a Start Printed Page 66385request to change the service bulletin reference as two separate issues.
- For each issue, state what specific change to the proposed AD is being requested.
- Include justification (e.g., reasons or data) for each request.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the proposed rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 2002-NM-288-AD.” The postcard will be date stamped and returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 2002-NM-288-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.
The FAA has received reports indicating that cracking was noticed during production of three Boeing Model 747-400F series airplanes. The cracking occurred on the section 42 skin panel assemblies at several fastener locations common to the body station 800 frame shear tie between stringers 13 and 15 on both the left and right sides of the airplanes. The maximum crack length was approximately 0.5 inch. Further investigation revealed that the cracks resulted from cyclic fatigue due to insufficient support at the tool attachment locations for the section 42 skin panel assemblies during shipment. Fatigue cracks in the fuselage skin and frame shear assemblies, if not detected and corrected, could propagate and result in undetected cracks and possible in-flight decompression of the airplane.
Boeing Model 747-400F series airplanes after line number 1286 have been inspected and show no damage. Section 42 skin panel assemblies on future Model 747-400F series airplanes will be shipped in a modified shipping fixture that provides improved support to prevent future damage. The section 42 skin panel assemblies for Boeing Model 747-100, -200B, -200C, -100B, -300, -100B SUD, -400, and “400D series airplanes have different shipping fixtures that provide adequate support. Therefore, these airplanes are not subject to the same unsafe condition identified in the 747-400F series airplanes having line numbers 968 through 1286, inclusive.
Explanation of Relevant Service Information
The FAA has reviewed and approved Boeing Special Attention Service Bulletin 747-53-2480, dated March 28, 2002, which describes procedures for repetitive detailed and general visual inspections of the external fuselage skin for cracks; various inspections of the affected area where cracks are found to determine the extent of the damage; and repair of cracks. Repair of a crack eliminates the need for the repetitive detailed and general visual inspections for that repair area only. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition.
Explanation of Requirements of Proposed Rule
Since an unsafe condition has been identified that is likely to exist or develop on other products of this same type design, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously, except as discussed below.
Differences Between Proposed Rule and Service Bulletin
Although the service bulletin specifies that operators may contact the manufacturer for an alternate repair for certain cracking conditions, this proposed AD would require operators to repair those conditions per a method approved by the FAA or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the FAA to make such findings.
There are approximately 72 airplanes of the affected design in the worldwide fleet. The FAA estimates that 12 airplanes of U.S. registry would be affected by this proposed AD, that it would take approximately 1 work hour per airplane to accomplish the proposed inspections, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the proposed AD on U.S. operators is estimated to be $780, or $65 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Manufacturer warranty remedies may be available for labor costs associated with this proposed AD. As a result, the costs attributable to the proposed AD may be less than stated above.
The regulations proposed herein 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. Therefore, it is determined that this proposal would not have federalism implications under Executive Order 13132.
For the reasons discussed above, I certify that 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) if promulgated, 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. A copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.Start List of Subjects
List of Subjects in 14 CFR Part 39
- Air transportation
- Aviation safety
The Proposed Amendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows:Start Part
PART 39—AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
2. Section 39.13 is amended by adding the following new airworthiness directive:
Boeing: Docket 2002-NM-288-AD.
Applicability: Model 747-400F series airplanes, having line numbers 968 through 1286 inclusive, certificated in any category.
Compliance: Required as indicated, unless accomplished previously.
To detect and correct fatigue cracks in the fuselage skin and frame shear tie assemblies, which could propagate and result in possible in-flight decompression of the airplane, accomplish the following:
Service Bulletin Reference
(a) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Special Attention Service Bulletin 747-53-2480, dated March 28, 2002.
(b) At the later compliance time specified in paragraphs (b)(1) and (b)(2) of this AD, do the inspections specified in paragraph (c) of this AD.
(1) Within 6,000 flight cycles after the date of issuance of the original Airworthiness Certificate or date of issuance of the Export Certificate of Airworthiness, whichever comes first.
(2) Within 3,000 flight cycles after the effective date of this AD.
(c) Perform both inspections of the external fuselage skin as shown in Table 1 of this AD, per the service bulletin. Repeat the inspections thereafter at intervals not to exceed 3,000 flight cycles.
|Type of inspection||Area to inspect|
|(1) Detailed||Inspect the skin surface for cracks initiating from the shear tie fasteners (14 locations on each side) common to the body station 800 frame between stringers S-13 and S-15 on both the left and right sides of the airplane.|
|(2) General||Inspect the skin surface at all fastener locations for cracks between body stations 780 to 800 and stringers S-13 through S-15 on both the left and right sides of the airplane.|
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 mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”
For the purposes of this AD, a general visual inspection is defined as: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
Crack Findings: Inspections and Repair
(d) If any crack is found during any inspection required by paragraph (c) of this AD, before further flight, do the actions specified in paragraphs (d)(1) and (d)(2) of this AD.
(1) Perform inspections of the affected area to determine the extent of the crack using the following applicable inspection methods, per the service bulletin: detailed inspection; open-hole high frequency eddy current (HFEC) inspection; surface HFEC inspection; and dye penetrant inspection.
(2) Repair any crack per the service bulletin. Where the service bulletin specifies contacting Boeing for an alternate repair method: Before further flight, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, or per data meeting the type certification basis of the airplane approved by a Boeing Company DER who has been authorized by the Manager, Seattle ACO, to make such findings.
Terminating Action for Repaired Area
(e) Accomplishment of the repair per paragraph (d)(2) of this AD ends the repetitive inspection requirements of paragraph (c) of this AD for that repaired area only.
Alternative Methods of Compliance
(f) In accordance with 14 CFR 39.19, the Manager, ACO, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD.
Issued in Renton, Washington, on November 20, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-29572 Filed 11-25-03; 8:45 am]
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