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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2010-0858; Directorate Identifier 2010-NM-183-AD]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: We propose to adopt a new airworthiness directive (AD) for certain Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This proposed AD would require modifying the thrust reverser inner walls, inspecting for damage of the upper and lower inner wall insulation blankets, measuring the electrical conductivity on the aluminum upper compression pads 2 and 3 as applicable, inspecting for discrepancies of the inner wall of the thrust reverser, and corrective actions if necessary. This proposed AD would also require, for certain airplanes, doing various concurrent actions (including replacing the inner wall blanket insulation, installing updated full-authority digital electronic control software, and modifying the thrust reverser inner wall and insulation blankets). This proposed AD results from reports of heat damage to the inner wall of the thrust reversers. We are proposing this AD to detect and correct such heat damage, which could result in separation of adjacent components and consequent structural damage to the airplane, damage to other airplanes, and injury to people on the ground.
 DATES: We must receive comments on this proposed AD by November 12, 2010.
 ADDRESSES: You may send comments by any of the following methods: *Federal eRulemaking Portal:*
                         Go to 
                        *http://www.regulations.gov.*
                         Follow the instructions for submitting comments.
                    *Fax:*
                         202-493-2251.
                    *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.
                    *Hand Delivery:*
                         U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. For service information identified in this proposed AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail 
                        *me.boecom@boeing.com;*
                         Internet 
                        *https://www.myboeingfleet.com.*
                         You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221. Examining the AD Docket You may examine the AD docket on the Internet at 
                    *http://www.regulations.gov;*
                     or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD 
                    ( print page 59168)
                    docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone 800-647-5527) is in the 
                    **ADDRESSES**
                     section. Comments will be available in the AD docket shortly after receipt.
 FOR FURTHER INFORMATION CONTACT: Chris Parker, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 425-917-6496; fax 425-917-6590.


SUPPLEMENTARY INFORMATION: Comments Invited We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the 
                    **ADDRESSES**
                     section. Include “Docket No. FAA-2010-0858; Directorate Identifier 2010-NM-183-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments. We will post all comments we receive, without change, to 
                    *http://www.regulations.gov,*
                     including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD. Discussion We have received reports of heat-related damage to the inner wall of the thrust reverser. During an inspection of a thrust reverser, one operator found heat damage at different locations of the inner wall: At the top, in the area of the number 2 and number 3 upper compression pads, and at the lower aft edge. A flight test at Boeing showed that the temperatures applied to the inner walls of the thrust reversers are too high. Higher temperatures are due to hot precooler air leakage between the inner wall of the thrust reverser and the insulation blankets and heat transfer through the upper compression pad area and the fireseal bracket support flange. Heat damage to the thrust reverser inner wall, if not corrected, could result in separation of adjacent components and consequent structural damage to the airplane, damage to other airplanes, and injury to people on the ground. Relevant Service Information We have reviewed the service bulletins identified in the following table. Service Information
Service Bulletin
Revision level
DateBoeing Service Bulletin 737-78-1082
Original
March 25, 2010.Boeing Service Bulletin 737-78-1088
Original
May 12, 2010.Boeing Service Bulletin 737-78-1079
2
June 7, 2010.Boeing Service Bulletin 737-78-1069
4
June 16, 2005.Boeing Service Bulletin 737-78-1063
2
October 7, 1999.CFM CFM56-7B Service Bulletin 73-0135
Original
March 30, 2007.
 Boeing Service Bulletin 737-78-1082 describes procedures for modifying the thrust reverser inner wall by drilling a hole through the inner wall behind the number 3 upper compression pad, and installing a bushing, applying sealant to areas of the insulation blankets, and installing flange insulation assemblies at the top aft edge of the upper insulation blanket. Boeing Service Bulletin 737-78-1088 describes procedures for the following: Detailed inspection for damage of the engine side and inner wall side of the upper and lower insulation blankets.
                Measurement of the electrical conductivity on the aluminum upper compression pads 2 and 3, as applicable.
                Inspections for discrepancies of the inner wall of the thrust reverser, including an ultrasonic inspection of the thrust reverser inner wall for interplay delamination and skin-to-core disbond.
                Detailed inspection, for certain airplanes, of the thrust reverser inner wall for signs of heat damage.
                Detailed inspection of the thrust reverser inner wall for indications of loose fasteners where the inner wall attaches to the hinge beam and at the fasteners for the compression pads.
                Corrective actions, including repairing or replacing damaged insulation blankets and repairing the thrust reverser inner wall (including replacing loose fasteners and contacting Boeing for a repair procedure), and replacing any unserviceable compression pad with a new one. Boeing Service Bulletin 737-78-1079 describes procedures for essentially the same actions (including inspections and modification) specified in Boeing Service Bulletins 737-78-1082 and 737-78-1088. Boeing Service Bulletin 737-78-1082 also specifies the concurrent accomplishment of the actions specified in Boeing Service Bulletin 737-78-1063: replacement of the inner wall blanket insulation. Boeing Service Bulletin 737-78-1082 also specifies the concurrent accomplishment of the actions specified in CFM CFM56-7B Service Bulletin 73-0135: installation of updated full-authority digital electronic control (FADEC) software. Boeing Service Bulletin 737-78-1088 specifies the concurrent accomplishment of the actions specified in Boeing Service Bulletin 737-78-1069: modification of the thrust reverser inner walls and insulation blankets. The modification involves installing additional supports on the inner wall of the thrust reverser for the attachment of the insulation blankets, installing new brackets to attach the forward edge of the upper and lower insulation blankets, installing additional attachment grommets to the blankets, and sealing the blankets at the forward edge of the fan duct inner walls. FAA's Determination and Requirements of This Proposed AD We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs. This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed below. Differences Between the Proposed AD and Service Information Although Boeing Service Bulletin 737-78-1088 specifies that operators may contact the manufacturer for disposition of certain repair conditions, this proposed AD would require operators to repair those conditions using a method approved by the FAA.
                    ( print page 59169) Clarification of Certain Terminology Where Boeing Service Bulletin 737-78-1088 refers to “unsatisfactory” findings, this proposed AD assumes those parts or locations are “unserviceable.” Costs of Compliance We estimate that this proposed AD would affect 710 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD, at an average labor rate of $85 per hour. Estimated Costs
Actions (Service Bulletin)
Work hours
Parts
Cost per product
Number of U.S.-registered airplanes
Fleet costModification (Boeing Service Bulletin 737-78-1082)
14 per engine
$2,065 or 3,702
$4,445 or 6,082
710
Up to $4,318,220.Insulation replacement (Boeing Service Bulletin 737-78-1063)
18 per engine
0
3,060
15
45,900Software update (CFM CFM56-7B Service Bulletin 73-0135)
1
0
85
Up to 710
Up to 60,350.Inspections (Boeing Service Bulletin 737-78-1088)
35
0
2,975
710
2,112,250Modifications (Boeing Service Bulletin 737-78-1069)
110
0
9,350
306
2,861,100Inspections and modification (Boeing Service Bulletin 737-78-1079) (if done as an option to Boeing Service Bulletin 737-78-1088 and Boeing Service Bulletin 737-78-1082)
37 per engine
2,070 or 3,391
8,360 or 9,681
Optional action
Optional action.
 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 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 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. 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. You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. List of Subjects in 14 CFR Part 39 Air transportation
Aircraft
Aviation safety
Incorporation by reference
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
  2. The FAA amends § 39.13 by adding the following new AD: **The Boeing Company:**
                                 Docket No. FAA-2010-0858; Directorate Identifier 2010-NM-183-AD. Comments Due Date (a) We must receive comments by November 12, 2010. Affected ADs (b) None. Applicability (c) This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes; certificated in any category; as identified in Boeing Service Bulletin 737-78-1082, dated March 25, 2010. Subject (d) Air Transport Association (ATA) of America Code 78: Engine exhaust. Unsafe Condition (e) This AD results from reports of heat damage to the inner wall of the thrust reversers. The Federal Aviation Administration is issuing this AD to detect and correct such heat damage, which could result in separation of adjacent components and consequent structural damage to the airplane, damage to other airplanes, and injury to people on the ground. Compliance (f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. Modification of Thrust Reverser Inner Wall (g) Except as required by paragraph (m) of this AD: Within 24 months after the effective date of this AD, modify the thrust reverser inner wall, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1082, dated March 25, 2010. Actions Concurrent With Paragraph (g) (h) Before or concurrently with accomplishment of the requirements of paragraph (g) of this AD, do the actions 
                                ( print page 59170)
                                specified in paragraphs (h)(1) and (h)(2) of this AD, as applicable. (1) For Model 737-600, -700, and -800 series airplanes identified in Boeing Service Bulletin 737-78-1063, Revision 2, dated October 7, 1999: Replace the inner wall blanket insulation, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1063, Revision 2, dated October 7, 1999. (2) For airplanes equipped with engines identified in CFM CFM56-7B Service Bulletin 73-0135, dated March 30, 2007: Install updated full-authority digital electronic control (FADEC) software, in accordance with the Accomplishment Instructions of CFM CFM56-7B Service Bulletin 73-0135, dated March 30, 2007. Inspection/Measurement (i) At the applicable time specified in paragraph (j) of this AD: Do the actions specified in paragraphs (i)(1), (i)(2), and (i)(3) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1088, dated May 12, 2010. If any damage or discrepancy is found, before further flight, do all applicable corrective actions, in accordance with Accomplishment Instructions of Boeing Service Bulletin 737-78-1088, dated May 12, 2010; except as required by paragraph (k) of this AD; and except where the service bulletin refers to “unsatisfactory” findings, this AD assumes those parts or locations are “unserviceable.” (1) Do a detailed inspection for damage of the engine side and inner wall side of the upper and lower insulation blankets. (2) Measure the electrical conductivity on the aluminum upper compression pads 2 and 3, as applicable. (3) Inspect for discrepancies of the thrust reverser inner wall (including an ultrasonic inspection for interplay delamination and skin-to-core disbond, a detailed inspection for signs of heat damage as applicable, and a detailed inspection for loose fasteners where the inner wall attaches to the hinge beam and at the fasteners for the compression pads). Compliance Times for Paragraph (i) (j) Do the actions specified in paragraph (i) of this AD at the applicable time specified in paragraph (j)(1), (j)(2), (j)(3), (j)(4), or (j)(5) of this AD. (1) For airplanes with thrust reverser part number (P/N) 315A2295-003 through 315A2295-154 inclusive: Do the actions within 30 months after the effective date of this AD. (2) For airplanes with thrust reverser P/N 315A2295-155 through 315A2295-174 inclusive: Do the actions within 60 months after the effective date of this AD. (3) For airplanes with thrust reverser P/N 315A2295-175 through 315A2295-190 inclusive: Do the actions within 72 months after the effective date of this AD. (4) For airplanes with thrust reverser P/N 315A2295-191 through 315A2295-198 inclusive: Do the actions within 84 months after the effective date of this AD. (5) For airplanes with thrust reverser P/N 315A2295-199 through 315A2295-202 inclusive: Do the actions within 96 months after the effective date of this AD. Exception to Boeing Service Bulletin 737-78-1088 Procedures (k) Where Boeing Service Bulletin 737-78-1088, dated May 12, 2010, specifies to contact Boeing for appropriate action, repair before further flight in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. 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. Actions Concurrent With Paragraph (i) (l) For airplanes identified in Boeing Service Bulletin 737-78-1069, Revision 4, dated June 16, 2005: Before or concurrently with the accomplishment of the requirements of paragraph (i) of this AD, modify the thrust reverser inner wall and insulation blankets, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-78-1069, Revision 4, dated June 16, 2005. A modification done before the effective date of this AD is also acceptable if done in accordance with Boeing Service Bulletin 737-78-1069, Revision 1, dated June 13, 2002; Revision 2, dated February 6, 2003; or Revision 3, dated August 5, 2004. (m) If the actions required by paragraph (i) of this AD are done before the compliance time specified in paragraph (g) of this AD: Before or concurrently with the accomplishment of the actions required by paragraph (i) of this AD, the modification required by paragraph (g) of this AD must be done. Option to Requirements of Paragraphs (g) and (i) (n) Accomplishment of all of the actions (including inspections and modification) specified in Boeing Service Bulletin 737-78-1079, Revision 2, dated June 7, 2010, within 24 months after the effective date of this AD, is acceptable for compliance with the requirements of paragraphs (g) and (i) of this AD and is acceptable for compliance with the requirements of this AD, provided applicable repairs are done before further flight, and provided the applicable actions specified in paragraphs (h)(1), (h)(2), and (l) of this AD have been done. Actions done before the effective date of this AD in accordance with Boeing Service Bulletin 737-78-1079, dated August 6, 2007; or Revision 1, dated December 17, 2007; are also acceptable for compliance with the corresponding actions specified in this paragraph. Alternative Methods of Compliance (AMOCs) (o)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to ATTN: Chris Parker, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 425-917-6496; fax 425-917-6590. Information may be e-mailed to: 
                                *9-ANM-Seattle-ACO-AMOC-Requests@faa.gov*. (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 principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically refer to this AD. Issued in Renton, Washington on September 15, 2010. Robert D. Breneman, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.


[FR Doc. 2010-24175 Filed 9-24-10; 8:45 am] BILLING CODE 4910-13-P