Airworthiness Directives; The Boeing Company Airplanes

[Federal Register Volume 78, Number 87 (Monday, May 6, 2013)]
[Rules and Regulations]
[Pages 26233-26241]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-08992]



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Federal Register / Vol. 78, No. 87 / Monday, May 6, 2013 / Rules and 
Regulations

[[Page 26233]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1231; Directorate Identifier 2011-NM-088-AD; 
Amendment 39-17418; AD 2013-08-01]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER 
series airplanes. This AD was prompted by reports of damaged fire seals 
on the forward edge of the thrust reverser. This AD requires inspecting 
to detect damage to the upper fire seals on the forward edge of the 
thrust reverser, where the fire seal contacts the 12-o'clock engine 
strut, and for correct stiffness and vent holes, and doing corrective 
actions if necessary; and installing a bracket for the fire seal. We 
are issuing this AD to detect and correct damage to the fire seals, 
which could allow airflow into the engine fire zone and could degrade 
the ability to extinguish an engine fire.

DATES: This AD is effective June 10, 2013.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of June 10, 
2013.

ADDRESSES: For service information identified in this 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; 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 docket contains this AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (phone: 800-647-5527) is Document Management Facility, 
U.S. Department of Transportation, Docket Operations, M-30, West 
Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Sue Lucier, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: 
425-917-6438; fax: 425-917-6590; email: [email protected].

SUPPLEMENTARY INFORMATION: 

Discussion

    We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR 
part 39 to include an AD that would apply to the specified products. 
That NPRM published in the Federal Register on November 18, 2011 (76 FR 
71472). That NPRM proposed to require inspecting to detect damage to 
the upper fire seals on the forward edge of the thrust reverser, where 
the fire seal contacts the 12-o'clock engine strut, and for correct 
stiffness and vent holes, and doing corrective actions if necessary; 
and installing a bracket for the fire seal.

Revised Service Information

    Since we published the NPRM (76 FR 71472, November 18, 2011), 
Boeing has issued Special Attention Service Bulletin 737-78-1086, 
Revision 1, dated May 15, 2012. That revision removes one airplane from 
the effectivity, updates and corrects certain illustrations and 
procedures, and states that no more work is necessary on airplanes 
changed in accordance with the original issue (Boeing Special Attention 
Service Bulletin 737-78-1086, dated October 6, 2010), which was 
specified as the appropriate source of service information in the NPRM.
    We have accordingly changed paragraphs (g), (g)(1), and (g)(2) of 
this final rule to specify Boeing Special Attention Service Bulletin 
737-78-1086, Revision 1, dated May 15, 2012; added paragraph (i) of 
this AD to give credit for actions done before the effective date of 
this AD using Boeing Special Attention Service Bulletin 737-78-1086, 
dated October 6, 2010; and reidentified subsequent paragraphs.
    However, the revised service bulletin, Boeing Special Attention 
Service Bulletin 737-78-1086, Revision 1, dated May 15, 2012, contains 
two errors, as follows:
    <bullet> Figure 10, Sheet 3 of 3: Note row (a) of the table shown 
in Figure 10, incorrectly refers the reader to ``(a)'' instead of Note 
row (b).
    <bullet> Figures 6, 7, 15, and 16, all Sheet 2 of 3, all View B: 
These illustrations show the top fastener to be removed in the center 
of three fasteners in order to remove the retainer. However, these 
three fasteners are adjustable sustained preload (ASP) fasteners that 
do not require removal for this action. View B also incorrectly shows 
the location of the top rivet hole, which is actually below the row of 
ASP fasteners. These errors in those figures affect the actions 
specified in paragraph (g)(2) of this AD. The other instructions in the 
figures are correct.
    To clarify the correct actions for paragraph (g)(2) of this AD, we 
have added paragraph (h) to this AD to describe these differences, and 
Figures 1 through 4 of this AD to show the correct fastener and rivet 
hole information.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 71472, November 18, 2011) and the FAA's response to each 
comment.

Request To Change the Unsafe Condition Statement

    Boeing requested that we rephrase the unsafe condition described in 
the Summary and paragraph (e) of the NPRM (76 FR 71472, November 18, 
2011). The commenter stated that damage to the fire seals or low 
stiffness

[[Page 26234]]

is the unsafe condition because either condition could allow increased 
airflow into the engine core compartment, which could reduce fire 
extinguishing concentrations. Boeing further stated that it has 
received no reports of damage to adjacent structure due to fire seal 
damage, but has received reports of damage to insulation blankets 
adjacent to the fire seal damage; it received no reports of damage with 
sealed blankets.
    We agree to revise the unsafe condition statements for the reasons 
given, and have changed the Summary and paragraph (e) of this AD 
accordingly.

Request for Terminating Action Statement

    American Airlines (AAL) requested that the NPRM (76 FR 71472, 
November 18, 2011) include a statement indicating that performing the 
required actions terminates the AD's requirements. AAL stated that fire 
seal inspections have regular maintenance requirements scheduled under 
Maintenance Review Board (MRB) items 78-090 and -100, which adequately 
monitor ongoing serviceability.
    We agree with AAL's request for the reason given. We have added the 
words ``one-time,'' which accurately describes the general visual 
inspection required by paragraph (g) of this AD. Because paragraphs 
(g)(1) and (g)(2) refer to the paragraph (g) inspection, those 
paragraphs need no change.

Request To Extend the Compliance Time

    AAL requested that the compliance time in paragraph (g) of the NPRM 
(76 FR 71472, November 18, 2011) be extended to 72 months from the date 
of the NPRM (76 FR 71472, November 18, 2011), rather than 36 months. 
AAL stated that the longer compliance time would eliminate an undue 
burden on operators by better coinciding with their heavy checks, and 
that the added time needed to replace or reseal the upper support 
flange on-wing affects their tighter C-check schedules. Further, the 
MRB seal inspections maintain an acceptable safety level.
    We do not agree to extend the compliance time. The proposed 
compliance time of 36 months after the AD effective date, will be well 
after the manufacturer's recommended action time of 36 months after the 
original issue date of Boeing Special Attention Service Bulletin 737-
78-1086, dated October 6, 2010.
    In developing an appropriate compliance time for this action, we 
considered the urgency associated with the subject unsafe condition, 
the availability of required parts, and the practical aspect of 
accomplishing the required inspection within a period of time that 
corresponds to the normal scheduled maintenance for most affected 
operators. However, under the provisions of paragraph (j) of this final 
rule, we will consider requests for approval of an extension of the 
compliance time if sufficient data are submitted to substantiate that 
the new compliance time would provide an acceptable level of safety. We 
have not changed the AD in this regard.

Request To Change Cost Information

    AAL requested that we increase the labor time in the ``Costs of 
Compliance'' section of the NPRM (76 FR 71472, November 18, 2011) to 
reflect the additional two work shifts needed for installation and cure 
time, plus the material cost of the new flange insulation. AAL stated 
that it prototyped the actions specified in Boeing Special Attention 
Service Bulletin 737-78-1086, dated October 6, 2010, and found that it 
added significant time to the light C-check, mostly due to a minimum of 
five work shifts to install and cure the flange insulation, during 
which time no rigging or operating of flight controls could be done.
    We agree to revise the cost information as follows, based on the 
new service information discussed in the ``New Service Information'' 
section above: ``Labor cost'' increased to 28 work-hours (14 hours per 
engine), and ``Parts cost'' to $2,494 ($1,247 per engine). The ``on-
condition costs'' remain unchanged.

Request To Include Later FAA-Approved Service Bulletin Revisions

    AAL requested that we allow compliance by any later FAA-approved 
revisions to Boeing Special Attention Service Bulletin 737-78-1086, 
Revision 1, dated May 15, 2012.
    We disagree to refer to later revisions to service information, 
because when referring to a specific service bulletin in an AD, we 
cannot use the phrase, ``or later FAA-approved revisions,'' due to 
Office of the Federal Register regulations for approving materials that 
are incorporated by reference. However, operators may request approval 
to use a later revision of the referenced service bulletin as an 
alternative method of compliance, under the provisions of paragraph (j) 
of the final rule. We have not changed the AD in this regard.

Request To Exclude Certain Parts of the Service Information

    AAL stated that Boeing Special Attention Service Bulletin 737-78-
1086, dated October 6, 2010, specifies actions that duplicate 
procedures given in the aircraft maintenance manual (AMM), or apply 
only to on-wing methods or not removing the thrust reverser, and 
requested that the NPRM (76 FR 71472, November 18, 2011) not mandate 
these actions for all airplanes and methods when they do not apply, or 
do not address the unsafe condition for that airplane. In one example, 
AAL described that if the thrust reverser is not removed, only the 
fire-seal compression check of AMM 78-31-12-4 or 87-31-01-5 (fire seal 
removal/installation, and thrust reverser adjustment/test, 
respectively) needs to be done, because the vee-blade depth and 
deflection limiter geometry do not change.
    We do not agree to exclude certain actions specified in the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-78-1086, Revision 1, dated May 15, 2012, from the 
requirements of this AD. Those instructions do not address 
accomplishing the work off-wing, other than stating that it can be 
done. The thrust reverser adjustment is included in the steps 
regardless of how the seal flange is installed, because adding the 
additional material in the stack-up might affect part fit-up and 
ultimately require re-rigging prior to releasing the airplane into 
service. Further, the service bulletin only refers to the AMM 
procedures, which gives operators flexibility in doing the work due to 
particular maintenance procedures not being mandated. We have not 
changed the AD in this regard.

Request To Correct Errors in, or Refer to, Revised Service Information

    AAL and Boeing submitted examples of errors in and corrections 
needed to Boeing Special Attention Service Bulletin 737-78-1086, dated 
October 6, 2010. AAL requested that the service information be 
corrected or revised, and Boeing requested that we incorporate Boeing 
Special Attention Service Bulletin 737-78-1086, Revision 1, dated May 
15, 2012, which Boeing stated corrects the items it identified.
    As discussed in the Revised Service Information section above, we 
agree to refer to the revised service information, including the two 
differences noted in that section.

Concern for Parts Availability

    AAL stated that there needs to be sufficient stock of seals 
available to

[[Page 26235]]

support replacements resulting from inspections done within the 
proposed compliance time. AAL found that in December 2011, the Boeing 
parts page on the Internet showed no available stock of the required 
seals and did not show a standard lead time for them, but projected 
dates in February and March of 2012.
    We infer that AAL requested that we delay issuing the AD until 
parts are available. We received information from Boeing that ample 
parts kits are now available to supply the fleet. We have not changed 
the AD in this regard.

Added Paragraph for Certain Alternative Methods of Compliance (AMOCs)

    We added new paragraph (j)(3) to this AD to allow AMOC requests 
approved by Boeing's Organization Designation Authorization (ODA).

Conclusion

    We reviewed the relevant data, considered the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously--and minor editorial 
changes. We have determined that these minor changes:
    <bullet> [Agr]re consistent with the intent that was proposed in 
the NPRM/(76 FR 71472, November 18, 2011) for correcting the unsafe 
condition; and
    <bullet> Do not add any additional burden upon the public than was 
already proposed in the NPRM/(76 FR 71472, November 18, 2011).
    We also determined that these changes will not increase the 
economic burden on any operator or increase the scope of the AD.

Costs of Compliance

    We estimate that this AD affects 968 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:


                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                    Cost per       Cost on U.S.
               Action                        Labor cost           Parts cost        product         operators
----------------------------------------------------------------------------------------------------------------
General visual inspection and         28 work-hours x $85 per          $2,494           $4,874       $4,718,032
 bracket installation.                 hour = $2,380.
----------------------------------------------------------------------------------------------------------------

    We estimate the following costs to do necessary repairs and 
replacements that would be required based on the results of the 
inspection. We have no way of determining the number of aircraft that 
might need these repairs.

                                               On-Condition Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                     Cost per
                    Action                                 Labor cost               Parts cost        product
----------------------------------------------------------------------------------------------------------------
Drill vent holes (up to 8)....................  1 work-hour x $85 per hour = $85              $0             $85
Replace fire seal (up to 4)...................  8 work-hours x $85 per hour =              8,010           8,690
                                                 $680.
----------------------------------------------------------------------------------------------------------------

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

    This AD will not have federalism implications under Executive Order 
13132. This AD will not have a substantial direct effect on the States, 
on the relationship between the national government and the States, or 
on the distribution of power and responsibilities among the various 
levels of government.
    For the reasons discussed above, I certify that this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979),
    (3) Will not affect intrastate aviation in Alaska, and
    (4) 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.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

2013-08-01 The Boeing Company: Amendment 39-17418; Docket No. FAA-
2011-1231; Directorate Identifier 2011-NM-088-AD.

(a) Effective Date

    This AD is effective June 10, 2013.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes; certificated in any 
category; line numbers 1 through 3028 inclusive.

[[Page 26236]]

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 78, Engine exhaust.

(e) Unsafe Condition

    This AD was prompted by reports of damaged upper fire seals on 
the forward edge of the thrust reversers. We are issuing this AD to 
detect and correct damage to the fire seals, which could allow 
airflow into the engine fire zone and could ultimately degrade the 
ability to extinguish an engine fire.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Inspections and Corrective Actions

    Within 36 months after the effective date of this AD: Do a one-
time general visual inspection of the left and right thrust reverser 
halves of each engine for damage to the upper fire seal, for 
stiffness of the upper fire seal, and for missing vent holes as 
applicable, in accordance with paragraph 3.B. of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-78-
1086, Revision 1, dated May 15, 2012, except as required by 
paragraph (h) of this AD.
    (1) If, during the inspection required by paragraph (g) of this 
AD, no upper fire seal damage is found, and the fire seal has the 
correct stiffness: Before further flight, drill vent holes if they 
are missing, and install a new bracket behind the upper fire seal 
retainer, in accordance with paragraph 3.B. of the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-78-
1086, Revision 1, dated May 15, 2012.
    (2) If, during the inspection required by paragraph (g) of this 
AD, upper fire seal damage or insufficient fire seal stiffness is 
found: Before further flight, install a new upper fire seal, drill 
vent holes if they are missing, and install a new bracket behind the 
upper fire seal retainer, in accordance with paragraph 3.B. of the 
Accomplishment Instructions of Boeing Special Attention Service 
Bulletin 737-78-1086, Revision 1, dated May 15, 2012, except as 
required by paragraph (h) of this AD.

(h) Exceptions to Required Service Information

    Where this AD refers to Boeing Special Attention Service 
Bulletin 737-78-1086, Revision 1, dated May 15, 2012, the following 
exceptions apply.
    (1) In that service bulletin, where Note row (a) of the table 
shown in Figure 10 refers to ``(a)'', it should instead refer to 
Note row (b).
    (2) Figures 1 and 3 of this AD, titled ``Fastener Removal of the 
Retainer Support on the Left (Right) Thrust Reverser Half,'' have 
View B showing the top fastener in the center of three adjustable 
sustained preload (ASP) fasteners. That top fastener does not 
require removal in order to remove the retainer. The figures in this 
AD point to the correct information for those fasteners.
    (3) Figures 2 and 4 of this AD, titled ``Installation of the New 
Bracket behind the Retainer Support on the Left (Right) Thrust 
Reverser Half,'' have View B showing the top rivet hole. That rivet 
hole is actually below the row of three ASP fasteners. The figures 
in this AD point to the correct information for those rivet holes.
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(i) Credit for Previous Actions

    This paragraph provides credit for actions required by 
paragraphs (g), (g)(1), and (g)(2) of this AD, if those actions were 
performed before the effective date of this AD using Boeing Special 
Attention Service Bulletin 737-78-1086, dated October 6, 2010, which 
is not incorporated by reference in this AD.

(j) Alternative Methods of Compliance (AMOCs)

    (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. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in the Related Information 
section of this AD. Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.
    (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 the 
Boeing Commercial Airplanes Organization Designation Authorization 
(ODA) that has been authorized by the Manager, Seattle ACO, to make 
those findings. For a repair method to be approved, the repair must 
meet the certification basis of the airplane, and the approval must 
specifically refer to this AD.

[[Page 26241]]

(k) Related Information

    For more information about this AD, contact Sue Lucier, 
Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue SW., Renton, 
Washington 98057-3356; phone: 425-917-6438; fax: 425-917-6590; 
email: [email protected].
    For service information identified in this 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; Internet https://www.myboeingfleet.com.

(l) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) Boeing Special Attention Service Bulletin 737-78-1086, 
Revision 1, dated May 15, 2012.
    (ii) Reserved.
    (3) For service information identified in this 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; Internet https://www.myboeingfleet.com.
    (4) You may view this service information at 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued in Renton, Washington, on April 3, 2013.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-08992 Filed 5-3-13; 8:45 am]
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