[Federal Register Volume 75, Number 186 (Monday, September 27, 2010)]
[Proposed Rules]
[Pages 59167-59170]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-24175]


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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


Airworthiness Directives; The Boeing Company Model 737-600, -700, 
-700C, -800, -900, and -900ER Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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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 [email protected]; 
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

[[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            Date
------------------------------------------------------------------------
Boeing Service Bulletin         Original........  March 25, 2010.
 737[dash]78[dash]1082.
Boeing Service Bulletin         Original........  May 12, 2010.
 737[dash]78[dash]1088.
Boeing Service Bulletin         2...............  June 7, 2010.
 737[dash]78[dash]1079.
Boeing Service Bulletin         4...............  June 16, 2005.
 737[dash]78[dash]1069.
Boeing Service Bulletin         2...............  October 7, 1999.
 737[dash]78[dash]1063.
CFM CFM56-7B Service Bulletin   Original........  March 30, 2007.
 73[dash]0135.
------------------------------------------------------------------------

    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.

[[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
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                                                                                                           Number of U.S.-
    Actions (Service Bulletin)            Work hours               Parts            Cost per product    registered airplanes          Fleet cost
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Modification (Boeing Service        14 per engine........  $2,065 or 3,702......  $4,445 or 6,082.....  710.................  Up to $4,318,220.
 Bulletin 737[dash]78[dash]1082).
Insulation replacement (Boeing      18 per engine........  0....................  3,060...............  15..................  45,900
 Service Bulletin
 737[dash]78[dash]1063).
Software update (CFM CFM56-7B       1....................  0....................  85..................  Up to 710...........  Up to 60,350.
 Service Bulletin 73[dash]0135).
Inspections (Boeing Service         35...................  0....................  2,975...............  710.................  2,112,250
 Bulletin 737-78-1088).
Modifications (Boeing Service       110..................  0....................  9,350...............  306.................  2,861,100
 Bulletin 737-78-1069).
Inspections and modification        37 per engine........  2,070 or 3,391.......  8,360 or 9,681......  Optional action.....  Optional action.
 (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).
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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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  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

[[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: [email protected].
    (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