Airworthiness Directives; Boeing Model 737-300, -400, and -500 Series Airplanes, 48597-48600 [E7-16668]

Download as PDF Federal Register / Vol. 72, No. 164 / Friday, August 24, 2007 / Proposed Rules Alternative Methods of Compliance (AMOCs) (j)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with 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 14 CFR 25.571, Amendment 45, and the approval must specifically refer to this AD. Issued in Renton, Washington, on August 14, 2007. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E7–16657 Filed 8–23–07; 8:45 am] BILLING CODE 4910–13–P DEPARTMENT OF TRANSPORTATION Federal Aviation Administration 14 CFR Part 39 [Docket No. FAA–2007–29043; Directorate Identifier 2007–NM–177–AD] RIN 2120–AA64 Airworthiness Directives; Boeing Model 737–300, –400, and –500 Series Airplanes Federal Aviation Administration (FAA), Department of Transportation (DOT). ACTION: Notice of proposed rulemaking (NPRM). rfrederick on PROD1PC67 with PROPOSALS AGENCY: SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for all Boeing Model 737–300, –400, and –500 series airplanes. This proposed AD would require revising the FAAapproved maintenance inspection program to include inspections that will give no less than the required damage tolerance rating for each structural significant item (SSI), doing repetitive inspections to detect cracks of all SSIs, and repairing cracked structure. This proposed AD results from a report of incidents involving fatigue cracking and corrosion in transport category airplanes that are approaching or have exceeded VerDate Aug<31>2005 14:16 Aug 23, 2007 Jkt 211001 their design service objective. We are proposing this AD to maintain the continued structural integrity of the entire fleet of Model 737–300, –400, and –500 series airplanes. DATES: We must receive comments on this proposed AD by October 9, 2007. ADDRESSES: Use one of the following addresses to submit comments on this proposed AD. • DOT Docket Web site: Go to https://dms.dot.gov and follow the instructions for sending your comments electronically. • Government-wide rulemaking Web site: Go to https://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: (202) 493–2251. • 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 the service information identified in this proposed AD. FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM–120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 917–6440; fax (425) 917–6590. 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 ‘‘FAA–2007–29043; Directorate Identifier 2007–NM–177–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 https:// 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 PO 00000 Frm 00007 Fmt 4702 Sfmt 4702 48597 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 DOT’s complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477–78), or you may visit https:// dms.dot.gov. Examining the Docket You may examine the AD docket on the Internet at https://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 (800) 647–5527) is located on the ground level 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 In the early 1980’s, as part of its continuing work to maintain the structural integrity of older transport category airplanes, we concluded that the incidence of fatigue cracking may increase as these airplanes reach or exceed their design service objective (DSO). In light of this, and as a result of increased utilization, and longer operational lives, we determined that a supplemental structural inspection program (SSIP) was necessary to maintain the continued structural integrity for all airplanes in the transport fleet. Issuance of Advisory Circular (AC) As a follow-on from that determination, we issued AC No. 91–56, ‘‘Supplemental Structural Inspection Program for Large Transport Category Airplanes,’’ dated May 6, 1981. That AC provides guidance material to manufacturers and operators for use in developing a continuing structural integrity program to ensure safe operation of older airplanes throughout their operational lives. This guidance material applies to transport airplanes that were certified under the fail-safe requirements of part 4b (‘‘Airplane Airworthiness, Transport Categories’’) of the Civil Air Regulations or damage tolerance structural requirements of part 25 (‘‘Airworthiness Standards: Transport Category Airplanes’’) of the Federal Aviation Regulations (FAR) (14 CFR part 25), and that have a maximum gross weight greater than 75,000 pounds. The procedures set forth in that AC are applicable to transport category E:\FR\FM\24AUP1.SGM 24AUP1 48598 Federal Register / Vol. 72, No. 164 / Friday, August 24, 2007 / Proposed Rules airplanes operated under subpart D (‘‘Special Flight Operations’’) of part 91 of the FAR (14 CFR part 91); part 121 (‘‘Operating Requirements: Domestic, Flag, and Supplemental Operations’’); part 125 (‘‘Certification and Operations: Airplanes having a Seating Capacity of 20 or More Passengers or a Maximum Payload of 6,000 Pounds or More’’); and part 135 (‘‘Operating Requirements: Commuter and On-Demand Operations’’) of the FAR (14 CFR parts 121, 125, and 135). The objective of the SSIP was to establish inspection programs to ensure timely detection of fatigue cracking. Development of the SSIP In order to evaluate the effect of increased fatigue cracking with respect to maintaining fail-safe design and damage tolerance of the structure of Boeing Model 737–300, –400, and –500 series airplanes, Boeing conducted a structural reassessment of those airplanes, using damage tolerance evaluation techniques. Boeing accomplished this reassessment using the criteria contained in AC No. 91–56, as well as Amendment 25–45 of section 25.571 (‘‘Damage-tolerance and fatigue evaluation of structure’’) of the FAR (14 CFR 25.571). During the reassessment, members of the airline industry participated with Boeing in working group sessions and developed the SSIP for Model 737–300, –400, and –500 series airplanes. Engineers and maintenance specialists from the FAA also supported these sessions. Subsequently, based on the working group’s recommendations, Boeing developed the Supplemental Structural Inspection Document (SSID). Relevant Service Information We have reviewed Boeing Models 737–300/400/500 Airplanes Document No. D6–82669, ‘‘Supplemental Structural Inspection Document,’’ Original Release, dated May 2007 (hereafter ‘‘the SSID’’). The SSID describes procedures for revising the FAA-approved maintenance inspection program to include inspections that will give no less than the required damage tolerance rating (DTR) for each supplemental significant item (SSI), doing repetitive inspections to detect cracks of all SSIs, and repairing cracked structure. Accomplishing the actions specified in the SSID is intended to adequately address the unsafe condition. FAA’s Determination and Requirements of the Proposed AD We have evaluated all pertinent information and identified an unsafe condition that is likely to exist or develop on other airplanes of this same type design. For this reason, we are proposing this AD, which would require the following actions: Paragraph (g) of the proposed AD would require incorporation of a revision into the FAA-approved maintenance inspection program that provides no less than the required DTR for each SSI listed in the SSID. Paragraph (h) of the proposed AD would require repetitive inspections to detect cracks of all SSIs. Paragraph (i) of the proposed AD would require repairing any cracked structure in accordance with a method approved by the FAA or an Authorized Representative (AR) for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the FAA to make those findings. Paragraph (j) of the proposed AD specifies the requirements of the inspection program for transferred airplanes. Before any airplane that is subject to this proposed AD can be added to an air carrier’s operations specifications, a program for doing the inspections required by this proposed AD must be established. Differences Between the Proposed AD and Service Information Section 3.0, ‘‘Structural Significant Items (SSIs)’’ of the SSID specifies a threshold of 66,000 flight cycles for accomplishing the initial inspections; however, it does not specify a grace period for airplanes that are near or have passed that threshold. This proposed AD would allow a grace period of 12 months after the effective date of the AD to incorporate the SSID into the FAA-approved maintenance inspection program. This proposed AD also would allow a grace period of 4,000 flight cycles measured from 12 months after the effective date of the AD to initiate the applicable inspections to detect cracks of all SSIs. The SSID does not specify instructions on how to repair certain conditions. This proposed AD would require repairing those conditions in one of the following ways: • Using a method that we approve; or • Using data that have been approved by an AR for the Boeing Commercial Airplanes Delegation Option Authorization Organization whom we have authorized to make those findings. Costs of Compliance There are about 1,961 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD. ESTIMATED COSTS Average labor rate per hour Work hours Revision of maintenance inspection program. Inspections ....................... rfrederick on PROD1PC67 with PROPOSALS Action 1,200 per operator (26 U.S. operators). 600 per airplane ............... The number of inspection work hours, as indicated above, is presented as if the accomplishment of the actions in this proposed AD are to be conducted as ‘‘stand alone’’ actions. However, in actual practice, these actions for the most part will be done coincidentally or in combination with normally scheduled airplane inspections and VerDate Aug<31>2005 13:20 Aug 23, 2007 Jkt 211001 $80 80 Frm 00008 Fmt 4702 Fleet cost $96,000 per operator ..... 599 $2,496,000. $48,000, per airplane, per inspection cycle. 599 $28,752,000 per inspection cycle. other maintenance program tasks. Therefore, the actual number of necessary additional inspection work hours will be minimal in many instances. Additionally, any costs associated with special airplane scheduling will be minimal. Further, compliance with this proposed AD would be a means of PO 00000 Number of U.S.-registered airplanes Cost Sfmt 4702 compliance with the aging airplane safety final rule (AASFR) for the baseline structure of Model 737–300, -400, and -500 series airplanes. The AASFR final rule requires certain operators to incorporate damage tolerance inspections into their maintenance inspection programs. These requirements are described in 14 E:\FR\FM\24AUP1.SGM 24AUP1 Federal Register / Vol. 72, No. 164 / Friday, August 24, 2007 / Proposed Rules CFR 121.370(a) and 129.16. Accomplishment of the actions required by this proposed AD will meet the requirements of these CFR sections for the baseline structure. The costs for accomplishing the inspection portion of this proposed AD were accounted for in the regulatory evaluation of the AASFR final rule. 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. rfrederick on PROD1PC67 with PROPOSALS 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. VerDate Aug<31>2005 13:20 Aug 23, 2007 Jkt 211001 48599 The Proposed Amendment Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows: the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120–0056. PART 39—AIRWORTHINESS DIRECTIVES Initial and Repetitive Inspections (h) Before the accumulation of 66,000 total flight cycles, or within 4,000 flight cycles measured from 12 months after the effective date of this AD, whichever occurs later, do the applicable initial inspections to detect cracks of all SSIs, in accordance with the SSID. Repeat the applicable inspections thereafter at the intervals specified in Section 3.0, ‘‘Implementation’’ of the SSID. 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 adding the following new airworthiness directive (AD): Boeing: Docket No. FAA–2007–29043; Directorate Identifier 2007–NM–177–AD. Comments Due Date (a) The FAA must receive comments on this AD action by October 9, 2007. Affected ADs (b) None. Applicability (c) This AD applies to all Boeing Model 737–300, –400, and –500 series airplanes, certificated in any category. Unsafe Condition (d) This AD results from a report of incidents involving fatigue cracking and corrosion in transport category airplanes that are approaching or have exceeded their design service objective. We are issuing this AD to maintain the continued structural integrity of the entire fleet of Model 737–300, –400, and –500 series airplanes. 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. Service Information (f) The term ‘‘the SSID,’’ as used in this AD, means Boeing Models 737–300/400/500 Airplanes Document No. D6–82669, ‘‘Supplemental Structural Inspection Document,’’ Original Release, dated May 2007. Revision of the FAA-Approved Maintenance Inspection Program (g) Before the accumulation of 66,000 total flight cycles, or within 12 months after the effective date of this AD, whichever occurs later, incorporate a revision into the FAAapproved maintenance inspection program that provides no less than the required damage tolerance rating (DTR) for each structural significant item (SSI) listed in the SSID. (The required DTR value for each SSI is listed in the SSID.) The revision to the maintenance inspection program must include and must be implemented in accordance with the procedures in Section 5.0, ‘‘Damage Tolerance Rating (DTR) System Application,’’ and Section 6.0, ‘‘SSI Discrepancy Reporting’’ of the SSID. Under PO 00000 Frm 00009 Fmt 4702 Sfmt 4702 Repair (i) If any cracked structure is found during any inspection required by paragraph (h) of this AD, before further flight, repair the cracked structure using a method approved in accordance with the procedures specified in paragraph (k) of this AD. Inspection Program for Transferred Airplanes (j) Before any airplane that is subject to this AD and that has exceeded the applicable compliance times specified in paragraph (h) of this AD can be added to an air carrier’s operations specifications, a program for the accomplishment of the inspections required by this AD must be established in accordance with paragraph (j)(1) or (j)(2) of this AD, as applicable. (1) For airplanes that have been inspected in accordance with this AD: The inspection of each SSI must be done by the new operator in accordance with the previous operator’s schedule and inspection method, or the new operator’s schedule and inspection method, at whichever time would result in the earlier accomplishment for that SSI inspection. The compliance time for accomplishment of this inspection must be measured from the last inspection accomplished by the previous operator. After each inspection has been done once, each subsequent inspection must be performed in accordance with the new operator’s schedule and inspection method. (2) For airplanes that have not been inspected in accordance with this AD: The inspection of each SSI required by this AD must be done either before adding the airplane to the air carrier’s operations specification, or in accordance with a schedule and an inspection method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. After each inspection has been done once, each subsequent inspection must be done in accordance with the new operator’s schedule. Alternative Methods of Compliance (AMOCs) (k)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with 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 E:\FR\FM\24AUP1.SGM 24AUP1 48600 Federal Register / Vol. 72, No. 164 / Friday, August 24, 2007 / Proposed Rules (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 approval must specifically refer to this AD. Issued in Renton, Washington, on August 12, 2007. Stephen P. Boyd, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. E7–16668 Filed 8–23–07; 8:45 am] BILLING CODE 4910–13–P FEDERAL TRADE COMMISSION 16 CFR Part 303 Rules and Regulations Under the Textile Fiber Products Identification Act Federal Trade Commission. Request for public comment. AGENCY: rfrederick on PROD1PC67 with PROPOSALS ACTION: SUMMARY: The Federal Trade Commission (‘‘Commission’’), pursuant to a petition filed by Mohawk Industries, Inc. (‘‘Mohawk’’), E. I. du Pont de Nemours and Company (‘‘DuPont’’), and PTT Poly Canada (‘‘PTT Canada’’) (all hereinafter ‘‘Petitioners’’) solicits comments on amending Rule 7(c) of the Rules and Regulations Under the Textile Fiber Products Identification Act (‘‘Textile Rules’’) to establish a new generic fiber subclass name and definition within the existing definition of ‘‘polyester’’ for a specifically proposed subclass of polyester fibers made from poly(trimethylene terephthalate) (‘‘PTT’’). Petitioners state that PTT fiber, while having the same general chemical composition of polyester, has distinctive features of durability, resilience, softness, and ability to stretch with recovery that make PTT fiber significantly more suitable than conventional polyester (‘‘PET’’) for carpet and apparel. This notice also seeks comments on whether to amend Rule 7(c) to broaden or clarify its definition of polyester to describe more accurately the molecular structure and physical characteristics of PTT and any similar fibers, in the event that the petition does not warrant the establishment of a new subclass for PTT. DATES: Comments will be accepted until November 12, 2007. VerDate Aug<31>2005 13:20 Aug 23, 2007 Jkt 211001 Interested parties are invited to submit written comments. Comments should refer to ‘‘16 CFR Part 303—Textile Rule 8, Mohawk, DuPont, and PTT Canada Comment, Matter No. P074201’’ to facilitate the organization of comments. A comment filed in paper form should include this reference both in the text and on the envelope, and should be mailed or delivered to the following address: Federal Trade Commission/Office of the Secretary, Room H-135 (Annex K), 600 Pennsylvania Avenue, N.W., Washington, D.C. 20580. Comments containing confidential material, however, must be filed in paper form, must be clearly labeled ‘‘Confidential,’’ and must comply with Commission Rule 4.9(c).1 The FTC is requesting that any comment filed in paper form be sent by courier or overnight service, if possible, because postal mail in the Washington area and at the Commission is subject to delay due to heightened security precautions. Comments filed in electronic form should be submitted by following the instructions on the web-based form at https://secure.commentworks.com/ftcMohawk, DuPont and PTT Canada Comment. To ensure that the Commission considers an electronic comment, you must file it on that webbased form. You may also visit https:// www.regulations.gov to read this Notice, and may file an electronic comment through that website. The Commission will consider all comments that www.regulations.gov forwards to it. The FTC Act and other laws the Commission administers permit the collection of public comments to consider and use in this proceeding as appropriate. The Commission will consider all timely and responsive public comments that it receives, whether filed in paper or electronic form. Comments received will be available to the public on the FTC website, to the extent practicable, at https://www.ftc.gov. As a matter of discretion, the FTC makes every effort to remove home contact information for individuals from the public comments it receives before placing those comments on the FTC website. More information, including routine uses permitted by the Privacy Act, may be found in the FTC’s ADDRESSES: 1 The comment must be accompanied by an explicit request for confidential treatment, including the factual and legal basis for the request, and must identify the specific portions of the comment to be withheld from the public record. The request will be granted or denied by the Commission’s General Counsel, consistent with applicable law and the public interest. See Commission Rule 4.9(c), 16 CFR 4.9(c). PO 00000 Frm 00010 Fmt 4702 Sfmt 4702 privacy policy at https://www.ftc.gov/ftc/ privacy.htm. FOR FURTHER INFORMATION CONTACT: Janice Podoll Frankle, Attorney, Division of Enforcement, Bureau of Consumer Protection, Federal Trade Commission, Washington, DC, 20580; (202) 326-3022. SUPPLEMENTARY INFORMATION: I. Background A. Statutory and Regulatory Framework The Textile Fiber Products Identification Act (‘‘Textile Act’’) requires certain disclosures in textile labeling and advertising, and authorizes the Commission to promulgate rules needed to enforce the Textile Act and establish generic fiber names. Section 4(b)(1) of the Textile Act states that a textile product is misbranded unless it is labeled to show, among other elements, the percentages, by weight, of the constituent fibers in the product, designated by their generic names and in order of predominance by weight. 15 U.S.C. 70b(b)(1). Section 4(c) provides that the same information required by section 4(b)(1) (except the percentages) must appear in written advertisements if any disclosure or implication of fiber content is made about a covered textile product. 15 U.S.C. 70b(c). Section 7(c) directs the Commission to promulgate such rules, including the establishment of generic names of manufactured fibers, as are necessary to enforce the Textile Act’s directives. 15 U.S.C. 70e(c). The Commission’s Textile Rules address the Textile Act’s fiber content disclosure requirements, including the establishment of generic fiber names. Rule 6 (16 CFR 303.6) requires manufacturers to use the generic names of the fibers contained in their textile products in making fiber content disclosures. Rule 7 of the Textile Rules (16 CFR 303.7) sets forth the generic names and definitions that the Commission has established for manufactured fibers. Rule 8 (16 CFR 303.8) describes the procedures for establishing new generic names. B. Procedural History On February 21, 2006, Petitioners petitioned the Commission for the establishment of a new generic subclass within the existing polyester category for fibers made from PTT2 and submitted a revised petition (‘‘Petition’’) 2 Mohawk sells a line of carpets manufactured from PTT under the trademark SmartStrand. DuPont markets PTT under the trademark Sorona. PTT Poly Canada markets PTT under the trademark Corterra Polymers. E:\FR\FM\24AUP1.SGM 24AUP1

Agencies

[Federal Register Volume 72, Number 164 (Friday, August 24, 2007)]
[Proposed Rules]
[Pages 48597-48600]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-16668]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-29043; Directorate Identifier 2007-NM-177-AD]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737-300, -400, and -500 
Series Airplanes

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

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for all Boeing Model 737-300, -400, and -500 series airplanes. This 
proposed AD would require revising the FAA-approved maintenance 
inspection program to include inspections that will give no less than 
the required damage tolerance rating for each structural significant 
item (SSI), doing repetitive inspections to detect cracks of all SSIs, 
and repairing cracked structure. This proposed AD results from a report 
of incidents involving fatigue cracking and corrosion in transport 
category airplanes that are approaching or have exceeded their design 
service objective. We are proposing this AD to maintain the continued 
structural integrity of the entire fleet of Model 737-300, -400, and -
500 series airplanes.

DATES: We must receive comments on this proposed AD by October 9, 2007.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
     DOT Docket Web site: Go to https://dms.dot.gov and follow 
the instructions for sending your comments electronically.
     Government-wide rulemaking Web site: Go to https://
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: (202) 493-2251.
     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 the service information identified in this 
proposed AD.

FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6440; fax (425) 917-6590.

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 ``FAA-2007-
29043; Directorate Identifier 2007-NM-177-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 https://
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 DOT's complete Privacy Act Statement in the 
Federal Register published on April 11, 2000 (65 FR 19477-78), or you 
may visit https://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at https://
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 (800) 647-5527) is located on the 
ground level 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

    In the early 1980's, as part of its continuing work to maintain the 
structural integrity of older transport category airplanes, we 
concluded that the incidence of fatigue cracking may increase as these 
airplanes reach or exceed their design service objective (DSO). In 
light of this, and as a result of increased utilization, and longer 
operational lives, we determined that a supplemental structural 
inspection program (SSIP) was necessary to maintain the continued 
structural integrity for all airplanes in the transport fleet.

Issuance of Advisory Circular (AC)

    As a follow-on from that determination, we issued AC No. 91-56, 
``Supplemental Structural Inspection Program for Large Transport 
Category Airplanes,'' dated May 6, 1981. That AC provides guidance 
material to manufacturers and operators for use in developing a 
continuing structural integrity program to ensure safe operation of 
older airplanes throughout their operational lives. This guidance 
material applies to transport airplanes that were certified under the 
fail-safe requirements of part 4b (``Airplane Airworthiness, Transport 
Categories'') of the Civil Air Regulations or damage tolerance 
structural requirements of part 25 (``Airworthiness Standards: 
Transport Category Airplanes'') of the Federal Aviation Regulations 
(FAR) (14 CFR part 25), and that have a maximum gross weight greater 
than 75,000 pounds. The procedures set forth in that AC are applicable 
to transport category

[[Page 48598]]

airplanes operated under subpart D (``Special Flight Operations'') of 
part 91 of the FAR (14 CFR part 91); part 121 (``Operating 
Requirements: Domestic, Flag, and Supplemental Operations''); part 125 
(``Certification and Operations: Airplanes having a Seating Capacity of 
20 or More Passengers or a Maximum Payload of 6,000 Pounds or More''); 
and part 135 (``Operating Requirements: Commuter and On-Demand 
Operations'') of the FAR (14 CFR parts 121, 125, and 135). The 
objective of the SSIP was to establish inspection programs to ensure 
timely detection of fatigue cracking.

Development of the SSIP

    In order to evaluate the effect of increased fatigue cracking with 
respect to maintaining fail-safe design and damage tolerance of the 
structure of Boeing Model 737-300, -400, and -500 series airplanes, 
Boeing conducted a structural reassessment of those airplanes, using 
damage tolerance evaluation techniques. Boeing accomplished this 
reassessment using the criteria contained in AC No. 91-56, as well as 
Amendment 25-45 of section 25.571 (``Damage-tolerance and fatigue 
evaluation of structure'') of the FAR (14 CFR 25.571). During the 
reassessment, members of the airline industry participated with Boeing 
in working group sessions and developed the SSIP for Model 737-300, -
400, and -500 series airplanes. Engineers and maintenance specialists 
from the FAA also supported these sessions. Subsequently, based on the 
working group's recommendations, Boeing developed the Supplemental 
Structural Inspection Document (SSID).

Relevant Service Information

    We have reviewed Boeing Models 737-300/400/500 Airplanes Document 
No. D6-82669, ``Supplemental Structural Inspection Document,'' Original 
Release, dated May 2007 (hereafter ``the SSID''). The SSID describes 
procedures for revising the FAA-approved maintenance inspection program 
to include inspections that will give no less than the required damage 
tolerance rating (DTR) for each supplemental significant item (SSI), 
doing repetitive inspections to detect cracks of all SSIs, and 
repairing cracked structure. Accomplishing the actions specified in the 
SSID is intended to adequately address the unsafe condition.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other airplanes 
of this same type design. For this reason, we are proposing this AD, 
which would require the following actions:
    Paragraph (g) of the proposed AD would require incorporation of a 
revision into the FAA-approved maintenance inspection program that 
provides no less than the required DTR for each SSI listed in the SSID.
    Paragraph (h) of the proposed AD would require repetitive 
inspections to detect cracks of all SSIs.
    Paragraph (i) of the proposed AD would require repairing any 
cracked structure in accordance with a method approved by the FAA or an 
Authorized Representative (AR) for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized by 
the FAA to make those findings.
    Paragraph (j) of the proposed AD specifies the requirements of the 
inspection program for transferred airplanes. Before any airplane that 
is subject to this proposed AD can be added to an air carrier's 
operations specifications, a program for doing the inspections required 
by this proposed AD must be established.

Differences Between the Proposed AD and Service Information

    Section 3.0, ``Structural Significant Items (SSIs)'' of the SSID 
specifies a threshold of 66,000 flight cycles for accomplishing the 
initial inspections; however, it does not specify a grace period for 
airplanes that are near or have passed that threshold. This proposed AD 
would allow a grace period of 12 months after the effective date of the 
AD to incorporate the SSID into the FAA-approved maintenance inspection 
program. This proposed AD also would allow a grace period of 4,000 
flight cycles measured from 12 months after the effective date of the 
AD to initiate the applicable inspections to detect cracks of all SSIs.
    The SSID does not specify instructions on how to repair certain 
conditions. This proposed AD would require repairing those conditions 
in one of the following ways:
     Using a method that we approve; or
     Using data that have been approved by an AR for the Boeing 
Commercial Airplanes Delegation Option Authorization Organization whom 
we have authorized to make those findings.

Costs of Compliance

    There are about 1,961 airplanes of the affected design in the 
worldwide fleet. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                     Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                        Number of U.S.-
             Action                  Work hours       Average labor                 Cost                  registered               Fleet cost
                                                      rate per hour                                        airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Revision of maintenance          1,200 per operator             $80  $96,000 per operator.............             599  $2,496,000.
 inspection program.              (26 U.S.
                                  operators).
Inspections....................  600 per airplane..              80  $48,000, per airplane, per                    599  $28,752,000 per inspection
                                                                      inspection cycle.                                  cycle.
--------------------------------------------------------------------------------------------------------------------------------------------------------

    The number of inspection work hours, as indicated above, is 
presented as if the accomplishment of the actions in this proposed AD 
are to be conducted as ``stand alone'' actions. However, in actual 
practice, these actions for the most part will be done coincidentally 
or in combination with normally scheduled airplane inspections and 
other maintenance program tasks. Therefore, the actual number of 
necessary additional inspection work hours will be minimal in many 
instances. Additionally, any costs associated with special airplane 
scheduling will be minimal.
    Further, compliance with this proposed AD would be a means of 
compliance with the aging airplane safety final rule (AASFR) for the 
baseline structure of Model 737-300, -400, and -500 series airplanes. 
The AASFR final rule requires certain operators to incorporate damage 
tolerance inspections into their maintenance inspection programs. These 
requirements are described in 14

[[Page 48599]]

CFR 121.370(a) and 129.16. Accomplishment of the actions required by 
this proposed AD will meet the requirements of these CFR sections for 
the baseline structure. The costs for accomplishing the inspection 
portion of this proposed AD were accounted for in the regulatory 
evaluation of the AASFR final rule.

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.


Sec.  39.13  [Amended]

    2. The Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

Boeing: Docket No. FAA-2007-29043; Directorate Identifier 2007-NM-
177-AD.

Comments Due Date

    (a) The FAA must receive comments on this AD action by October 
9, 2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to all Boeing Model 737-300, -400, and -500 
series airplanes, certificated in any category.

Unsafe Condition

    (d) This AD results from a report of incidents involving fatigue 
cracking and corrosion in transport category airplanes that are 
approaching or have exceeded their design service objective. We are 
issuing this AD to maintain the continued structural integrity of 
the entire fleet of Model 737-300, -400, and -500 series airplanes.

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.

Service Information

    (f) The term ``the SSID,'' as used in this AD, means Boeing 
Models 737-300/400/500 Airplanes Document No. D6-82669, 
``Supplemental Structural Inspection Document,'' Original Release, 
dated May 2007.

Revision of the FAA-Approved Maintenance Inspection Program

    (g) Before the accumulation of 66,000 total flight cycles, or 
within 12 months after the effective date of this AD, whichever 
occurs later, incorporate a revision into the FAA-approved 
maintenance inspection program that provides no less than the 
required damage tolerance rating (DTR) for each structural 
significant item (SSI) listed in the SSID. (The required DTR value 
for each SSI is listed in the SSID.) The revision to the maintenance 
inspection program must include and must be implemented in 
accordance with the procedures in Section 5.0, ``Damage Tolerance 
Rating (DTR) System Application,'' and Section 6.0, ``SSI 
Discrepancy Reporting'' of the SSID. Under the provisions of the 
Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.), the Office 
of Management and Budget (OMB) has approved the information 
collection requirements contained in this AD and has assigned OMB 
Control Number 2120-0056.

Initial and Repetitive Inspections

    (h) Before the accumulation of 66,000 total flight cycles, or 
within 4,000 flight cycles measured from 12 months after the 
effective date of this AD, whichever occurs later, do the applicable 
initial inspections to detect cracks of all SSIs, in accordance with 
the SSID. Repeat the applicable inspections thereafter at the 
intervals specified in Section 3.0, ``Implementation'' of the SSID.

Repair

    (i) If any cracked structure is found during any inspection 
required by paragraph (h) of this AD, before further flight, repair 
the cracked structure using a method approved in accordance with the 
procedures specified in paragraph (k) of this AD.

Inspection Program for Transferred Airplanes

    (j) Before any airplane that is subject to this AD and that has 
exceeded the applicable compliance times specified in paragraph (h) 
of this AD can be added to an air carrier's operations 
specifications, a program for the accomplishment of the inspections 
required by this AD must be established in accordance with paragraph 
(j)(1) or (j)(2) of this AD, as applicable.
    (1) For airplanes that have been inspected in accordance with 
this AD: The inspection of each SSI must be done by the new operator 
in accordance with the previous operator's schedule and inspection 
method, or the new operator's schedule and inspection method, at 
whichever time would result in the earlier accomplishment for that 
SSI inspection. The compliance time for accomplishment of this 
inspection must be measured from the last inspection accomplished by 
the previous operator. After each inspection has been done once, 
each subsequent inspection must be performed in accordance with the 
new operator's schedule and inspection method.
    (2) For airplanes that have not been inspected in accordance 
with this AD: The inspection of each SSI required by this AD must be 
done either before adding the airplane to the air carrier's 
operations specification, or in accordance with a schedule and an 
inspection method approved by the Manager, Seattle Aircraft 
Certification Office (ACO), FAA. After each inspection has been done 
once, each subsequent inspection must be done in accordance with the 
new operator's schedule.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle ACO, has the authority to approve 
AMOCs for this AD, if requested in accordance with 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

[[Page 48600]]

(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 approval must specifically refer 
to this AD.

    Issued in Renton, Washington, on August 12, 2007.
Stephen P. Boyd,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E7-16668 Filed 8-23-07; 8:45 am]
BILLING CODE 4910-13-P
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