Document ID: FAA-2011-1411-0014
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: The Boeing Company Airplanes
Posted Date: 2012-10-03T04:00Z

[Federal Register Volume 77, Number 192 (Wednesday, October 3, 2012)]
[Rules and Regulations]
[Pages 60296-60301]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2012-23800]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1411; Directorate Identifier 2011-NM-074-AD; 
Amendment 39-17206; AD 2012-19-11]
RIN 2120-AA64

Airworthiness Directives; The Boeing Company Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
The Boeing Company Model 737 airplanes. This AD was prompted by a 
report of a flightcrew not receiving an aural warning during a lack of 
cabin pressurization event. This AD requires incorporating design 
changes to improve the reliability of the cabin altitude warning system 
by installing a redundant cabin altitude pressure switch, replacing the 
aural warning module (AWM) with a new or reworked AWM, and changing 
certain wire bundles or connecting certain previously capped and stowed 
wires as

[[Page 60297]]

necessary. For certain airplanes, this AD also requires prior or 
concurrent incorporation of related design changes by modifying the 
instrument panels, installing light assemblies, modifying the wire 
bundles, and installing a new circuit breaker, as necessary. We are 
issuing this AD to prevent the loss of cabin altitude warning, which 
could delay flightcrew recognition of a lack of cabin pressurization, 
and could result in incapacitation of the flightcrew due to hypoxia (a 
lack of oxygen in the body), and consequent loss of control of the 
airplane.

DATES: This AD is effective November 7, 2012.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in the AD as of November 7, 
2012.

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: Francis Smith, Aerospace Engineer, 
Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle 
Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 
98057-3356; phone: (425) 917-6596; fax: (425) 917-6590; email: 
Francis.Smith@faa.gov.

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 December 30, 2011 (76 FR 
82207). That NPRM proposed to require incorporating design changes to 
improve the reliability of the cabin altitude warning system by 
requiring installation of a redundant switch of the cabin altitude 
pressure, replacing the AWM with a new or reworked AWM, changing 
certain wire bundles, and connecting certain previously capped and 
stowed wires, as necessary. For certain airplanes, that NPRM also 
proposed to require modifying the instrument panels, installing light 
assemblies, modifying the wire bundles, and installing a new circuit 
breaker, as necessary.

Comments

    We gave the public the opportunity to participate in developing 
this AD. The following presents the comments received on the proposal 
(76 FR 82207, December 30, 2011) and the FAA's response to each 
comment.

Support for NPRM (76 FR 82207, December 30, 2011)

    Air Line Pilot's Association International supported the intent and 
the language of the NPRM (76 FR 82207, December 30, 2011). Europe 
Airpost stated it has no objection to the NPRM as proposed for Model 
737-700 airplanes. American Airlines (AAL) stated it has no objections 
to the NPRM as proposed and finds the proposed compliance time to be 
acceptable.

Request To Use the Latest Service Information

    Delta (DAL), AAL, and The Boeing Company requested that the 
proposed AD (76 FR 82207, December 30, 2011) incorporate ``Boeing 
Special Attention Service Bulletin 737-21-1165, Revision 2, dated April 
30, 2012,'' instead of Boeing Special Attention Service Bulletin 737-
21-1165, Revision 1, dated July 16, 2010. Boeing stated that Boeing 
Special Attention Service Bulletin 737-21-1165, Revision 2, dated April 
30, 2012, incorporates changes to fix errors in the airplane 
maintenance manual, connection pin contacts, one splice, and one wire 
that had been discovered by an operator attempting to incorporate the 
service information. Boeing stated that if Boeing Special Attention 
Service Bulletin 737-21-1165, Revision 1, dated July 16, 2010, is 
required, the operators affected by the errors in that service bulletin 
will require alternative methods of compliance (AMOCs) in order to 
comply with the proposed AD.
    In addition, Boeing and US Airways requested that the proposed AD 
(76 FR 82207, December 30, 2011) incorporate Boeing Special Attention 
Service Bulletin 737-21-1164, Revision 1, dated May 17, 2012. Boeing 
stated that this revised service information incorporates changes from 
an engineering validation that affects all identified airplane groups 
and revises the engineering for airplanes with cold-bonded skins. 
Boeing stated that Boeing Special Attention Service Bulletin 737-21-
1164, dated February 10, 2011, cannot be incorporated as written due to 
erroneous installation steps for the pressure switch location and 
erroneous operational test instructions. US Airways noted that errors 
with conflicting steps in Boeing Special Attention Service Bulletin 
737-21-1164, dated February 10, 2011, involve circuit breaker 
operation.
    We agree with the commenters' requests to reference the latest 
service information for the reasons provided by the commenters. We have 
revised this AD by referencing Boeing Special Attention Service 
Bulletin 737-21-1164, Revision 1, dated May 17, 2012; and Boeing 
Special Attention Service Bulletin 737-21-1165, Revision 1, dated July 
16, 2010, as revised by Boeing Special Attention Service Bulletin 737-
21-1165, Revision 2, dated April 30, 2012; throughout the AD. We have 
also given credit for actions done before the effective date of this AD 
in accordance with Boeing Special Attention Service Bulletin 737-21-
1165, Revision 1, dated July 16, 2010.

Request To Clarify or Delete Service Information

    Boeing requested that we either delete or clarify references in the 
preamble and paragraph (i) (``Credit for Actions Accomplished in 
Accordance with Previous Service Information'') of the NPRM (76 FR 
82207, December 30, 2011) to Boeing Alert Service Bulletin 737-31A1325, 
dated January 11, 2010, and Boeing Alert Service Bulletin 737-31A1332, 
Revision 2, dated August 18, 2011; as well as the supporting BAE 
Systems service information. Boeing stated a concern that the 
references to all of this service information will cause confusion 
regarding the concurrent requirements and compliance times.
    Boeing also stated that AD 2011-03-14, Amendment 39-16598 (76 FR 
6529, February 7, 2011), already mandates incorporation of Boeing Alert 
Service Bulletin 737-31A1325, dated January 11, 2010, and also 
establishes the compliance time. Boeing added that another existing 
NPRM, Docket No. FAA-2011-0258 (76 FR 16579, March 24, 2011), proposes 
to mandate Boeing

[[Page 60298]]

Alert Service Bulletin 737-31A1332, Revision 1, dated June 24, 2010, 
and it also establishes the compliance times.
    Boeing stated its concern that the proposed AD (76 FR 82207, 
December 30, 2011) might inadvertently require operators to incorporate 
Boeing Special Attention Service Bulletin 737-21-1164, Revision 1, 
dated May 17, 2012; and Boeing Alert Service Bulletin 737-31A1325, 
dated January 11, 2010; at the same time--instead of in the correct 
order.
    We agree with Boeing's request to clarify or delete certain service 
information in this final rule to avoid confusion.
    Notes 1 and 2 of the NPRM (76 FR 82207, December 30, 2011) 
referenced the supporting BAE Systems service information; therefore, 
we have removed those notes from this final rule to avoid confusion.
    It should be noted that since the issuance of the NPRM (76 FR 
82207, December 30, 2011), we have reviewed Boeing Alert Service 
Bulletin 737-31A1332, Revision 3, dated March 28, 2012, which clarifies 
certain actions and figures. We have revised paragraph (h) of this AD 
to reference this latest revision of the service information.
    We have also revised paragraph (i) of the NPRM (76 FR 82207, 
December 30, 2011), which gave credit for Boeing Alert Service Bulletin 
737-31A1332, Revision 1, dated June 24, 2010. Paragraph (i)(1) of this 
final rule provides credit for Boeing Special Attention Service 
Bulletin 737-21-1165, Revision 1, dated July 16, 2010. We have added 
paragraph (i)(2) to this final rule to give credit for Boeing Alert 
Service Bulletin 737-31A1332, Revision 1, dated June 24, 2010; however, 
such credit only applies to Group 1 airplanes identified in that 
service information, except for Groups 24, 25, and 27 through 33 
airplanes (as identified in Boeing Alert Service Bulletin 737-31A1332, 
Revision 3, dated March 28, 2012). Paragraphs (i)(3) and (i)(4) of this 
final rule to provide credit for Boeing Alert Service Bulletin 737-
31A1332, Revision 2, dated August 18, 2011, but only for the airplanes 
identified in those paragraphs.
    We provide the following clarifications for references in this 
final rule to Boeing Alert Service Bulletin 737-31A1325, dated January 
11, 2010; and Boeing Alert Service Bulletin 737-31A1332, Revision 2, 
dated August 18, 2011; as applicable.
    If an operator decides to comply with the actions in Boeing Special 
Attention Service Bulletin 737-21-1164, Revision 1, dated May 17, 2012; 
and Boeing Special Attention Service Bulletin 737-21-1165, Revision 1, 
dated July 16, 2010, as revised by Boeing Special Attention Service 
Bulletin 737-21-1165, Revision 2, dated April 30, 2012; within the 72-
month compliance time specified in this AD, then prior to or 
concurrently with those actions, the operator also must accomplish the 
concurrent requirements in Boeing Alert Service Bulletin 737-31A1325, 
dated January 11, 2010, or Boeing Alert Service Bulletin 737-31A1332, 
Revision 3, dated March 28, 2012, as applicable.
    However, we note that AD 2011-03-14, Amendment 39-16598 (76 FR 
6529, February 7, 2011), requires accomplishment of Boeing Alert 
Service Bulletin 737-31A1325, dated January 11, 2010, within 36 months 
after the effective date of that AD. In addition, NPRM Docket No. FAA-
2011-0258 (76 FR 16579, March 24, 2011) also specifies 36 months as the 
compliance time for accomplishment of Boeing Alert Service Bulletin 
737-31A1332, Revision 1, dated June 24, 2010. Therefore, if an operator 
waits until the end of the 72-month compliance time specified in 
paragraph (g) this AD to accomplish the concurrent service information 
specified in this AD--i.e., Boeing Alert Service Bulletin 737-31A1325, 
dated January 11, 2010; and Boeing Alert Service Bulletin 737-31A1332, 
Revision 3, dated March 28, 2012--then that operator would be out of 
compliance with the other AD actions. Therefore, the order of these AD 
actions is acceptable.

Request To Revise Unsafe Condition

    Boeing requested that paragraph (e) of the NPRM (76 FR 82207, 
December 30, 2011) be revised. Boeing suggested that the paragraph 
state: ``This AD was prompted by the report of a flight crew not 
receiving an aural warning during a lack of cabin pressurization event. 
The failure of the altitude pressure switch prevented the aural warning 
from sounding when the cabin altitude exceeded 10,000 feet. We are 
issuing this AD to improve reliability of the Cabin Altitude Warning to 
flight crews. Loss of the Cabin Altitude Warning may delay flight crew 
recognition of a lack of cabin pressurization, which could result in 
incapacitation of the flightcrew due to hypoxia (a lack of oxygen in 
the body), and consequent loss of control of the airplane.''
    Boeing stated that the pressure switch at issue is only used in the 
cabin altitude warning system and is not used for pressurization 
control. Boeing stated that the increased reliability of the cabin 
altitude warning may prevent delays in the flightcrew's recognition of 
a lack of cabin pressure event, but will not affect the flightcrew's 
ability to recognize the warning intent or properly react because the 
method of annunciation and associated flightcrew procedures are 
unchanged. Boeing stated that AD 2011-03-14, Amendment 39-16598 (76 FR 
6529, February 7, 2011), and NPRM Docket No. FAA-2011-0258 (76 FR 
16579, March 24, 2011) address the failure of a flightcrew to recognize 
and react to a valid cabin altitude warning.
    We agree with Boeing's request. We agree that the requested 
revision clarifies that failure of the pressure switch was not the root 
cause of the lack of cabin pressurization, but was the root cause of 
the failure of the aural warning. We have changed the Summary and 
paragraph (e) of this final rule accordingly, with certain editorial 
changes.

Request To Match Compliance Times of Two AD Actions

    United Airlines (UAL) requested that the effective date of the 
final rule after the NPRM (76 FR 82207, December 30, 2011) match the 
effective date of the final rule after NPRM for Docket No. FAA-2011-
0258 (76 FR 16579, March 24, 2011). UAL pointed out that Boeing Special 
Attention Service Bulletin 737-21-1165, Revision 2, dated April 30, 
2012; and Boeing Alert Service Bulletin 737-31A1332, Revision 2, dated 
August 18, 2011; have been issued. UAL stated that the effective date 
of this final rule will require installation of the redundant pressure 
switch (which was proposed in the NPRM (76 FR 82207, December 30, 
2011)), and should not precede the effective date of the final rule for 
NPRM Docket No. FAA-2011-0258, which currently proposes to require the 
installation of annunciators. UAL stated that matching the compliance 
times for the two final rules will allow operators to obtain parts and 
schedule the two modifications concurrently, which is much more 
effective than doing the two tasks at separate times, since the work is 
required in the same areas for both modifications.
    We disagree with the commenter's request to harmonize the 
compliance times. While we note that the safety issues identified in 
this final rule and NPRM Docket No. FAA-2011-0258 (76 FR 16579, March 
24, 2011) are related, each AD action addresses separate safety issues 
and has specific compliance times based on our risk assessments. 
Operators can always comply with an AD in advance of the compliance 
time. We have not changed this AD in this regard.

[[Page 60299]]

Request To Revise the Costs of Compliance Section

    Boeing requested clarification of incorporation costs reflected in 
the NPRM as those costs relate to Boeing Alert Service Bulletin 737-
31A1325, dated January 11, 2010; Boeing Alert Service Bulletin 737-
31A1332, Revision 2, dated August 18, 2011; and the supporting BAE 
service information.
    DAL requested that the work-hours for Boeing Alert Service Bulletin 
737-31A1332, Revision 2, dated August 18, 2011, to modify instrument 
panels, install light assemblies, modify wire bundles, and install a 
new circuit breaker, be changed from 84 to approximately 95. DAL stated 
that it has noted a discrepancy in the work-hours for the actions 
specified in the service information, excluding time estimates for 
opening and closing.
    AAL requested that we revise the estimated work-hours for 
accomplishing the actions in the NPRM (76 FR 82207, December 30, 2011). 
AAL suggested that the work-hours specified in Boeing Special Attention 
Service Bulletin 737-21-1165, Revision 1, dated July 16, 2010, be 
revised from 31 to approximately 95 work-hours for accomplishing the 
installation of the redundant cabin altitude pressure switch, removal 
and installation of the AWM, and wiring changes. AAL stated that it has 
validated its estimates through implementation on several airplanes. 
DAL requested the work-hours for the same action be adjusted to 
approximately 53.
    UAL requested that the combined work-hours for both actions (we 
infer to this as installation and modification) be changed from 115 to 
200 work-hours. UAL stated that it has done surveys of airplanes to 
determine how to gain access to affected areas, and it has determined 
what additional testing will be required due to disturbed systems.
    Europe Airpost, DAL, US Airways, and UAL requested that we revise 
the cost of parts in the NPRM (76 FR 82207, December 30, 2011). Europe 
Airpost specifically stated that an additional cost should be included 
for operators needing to procure a new AWM ($36,456 based on the Boeing 
service information), which is not negligible for small airlines. UAL 
stated that the price estimates specified in the service information 
and the NPRM only include wire kit costs and do not include the costs 
for modifying or replacing parts. US Airways indicated that the cost 
for reworking the AWM would be $4,136, and the cost for replacement of 
the AWM would be $33,576 (each).
    We agree with the commenters' request to revise the work-hours and 
the cost of parts in this AD. We have revised the cost for the 
installation, replacement, and wiring changes to include the 54 work-
hours in Boeing Special Attention Service Bulletin 737-21-1165, 
Revision 1, dated July 16, 2010, as revised by Boeing Special Attention 
Service Bulletin 737-21-1165, Revision 2, dated April 30, 2012, and the 
8 hours in the concurrent BAE service information, a total of up to 62 
work-hours. We have revised the cost of parts of the AWM to specify 
$33,576. For the modification and other installations, we have included 
the 8 work-hours in the concurrent BAE service information, a total of 
up to 92 work-hours. We have revised the ``Cost of Compliance'' section 
of this AD accordingly.

Request To Reopen the Comment Period for a Related NPRM (76 FR 16579, 
March 24, 2011)

    UAL requested that we revise and re-open the comment period for a 
related NPRM, Docket No. FAA-2011-0258 (76 FR 16579, March 24, 2011). 
UAL stated that the related NPRM is only applicable to airplanes in 
Groups 1 through 7 of Boeing Alert Service Bulletin 737-31A1332, 
Revision 1, dated June 24, 2010. UAL stated that it does not have any 
airplanes within these groups and, therefore, did not comment on that 
related NPRM. However, UAL stated that in paragraph (h) of the NPRM (76 
FR 82207, December 30, 2011), the concurrent requirements identified in 
Boeing Alert Service Bulletin 737-31A1332, Revision 2, dated August 18, 
2011, now include 23 groups of airplanes. UAL stated that operators 
that have airplanes in groups 1 through 7 likely did not comment on the 
related NPRM, and should be given the opportunity to do so.
    We are considering additional AD rulemaking at this time for the 
related NPRM, Docket No. FAA-2011-0258 (76 FR 16579, March 24, 2011), 
which will re-open the comment period.

Request for Editorial Changes

    Boeing requested that we make editorial changes to the NPRM (76 FR 
82207, December 30, 2011). Boeing suggested we delete the comma after 
``certain wire bundles,'' and add the word ``or'' so that the first 
sentence in paragraph (g) of the NPRM would read as follows: ``Within 
72 months after the effective date of this AD, install a redundant 
switch of the cabin altitude pressure, replace the aural warning module 
(AWM) with a new or reworked AWM, and change certain wire bundles or 
connect certain capped and stowed wires, as applicable * * *.'' Boeing 
noted that certain airplanes require the replacement of the AWM and 
connection of the capped and stowed wires, as specified in Boeing 
Special Attention Service Bulletin 737-21-1165, Revision 2, dated April 
30, 2012.
    We agree with the commenter's request for editorial changes for the 
reason provided by the commenter. We have changed the Summary and 
paragraph (g) of this final rule accordingly.

Revised AMOC Paragraph

    We have added paragraph (j)(3) to this final rule to delegate the 
authority to approve an AMOC for any repair required by this AD to the 
Boeing Commercial Airplanes 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:
     Are consistent with the intent that was proposed in the 
(NPRM (76 FR 82207, December 30, 2011) for correcting the unsafe 
condition; and
     Do not add any additional burden upon the public than was 
already proposed in the NPRM (76 FR 82207, December 30, 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 1,405 airplanes of U.S. registry.
    We estimate the following costs to comply with this AD:

[[Page 60300]]

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                 Cost on U.S.
              Action                    Labor cost        Parts cost      Cost per product        operators
----------------------------------------------------------------------------------------------------------------
Install a redundant cabin          Up to 62                    $33,576  Up to $38,846......  Up to $54,578,630.
 altitude pressure switch,          work[dash]hours x
 replace the AWM with a new or      $85 per hour = up
 reworked AWM, change certain       to $5,270.
 wire bundles or connect certain
 capped and stowed wires.
Modify the instrument panels,      Up to 92                      5,292  Up to $13,112......  Up to $18,422,360.
 install light assemblies, modify   work[dash]hours x
 the wire bundles, and install a    $85 per hour = up
 new circuit breaker (concurrent    to $7,820.
 requirements).
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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

    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):

2012-19-11 The Boeing Company: Amendment 39-17206; Docket No. FAA-
2011-1411; Directorate Identifier 2011-NM-074-AD.

(a) Effective Date

    This AD is effective November 7, 2012.

(b) Affected ADs

    None.

(c) Applicability

    The Boeing Company airplanes; certificated in any category; as 
identified in paragraphs (c)(1) and (c)(2) of this AD.
    (1) Model 737-100, -200, -200C, -300,-400, and -500 series 
airplanes, as identified in Boeing Special Attention Service 
Bulletin 737-21-1164, Revision 1, dated May 17, 2012.
    (2) Model 737-600, -700, -700C, -800,-900, and -900ER series 
airplanes, as identified in Boeing Special Attention Service 
Bulletin 737-21-1165, Revision 1, dated July 16, 2010, as revised by 
Boeing Special Attention Service Bulletin 737-21-1165, Revision 2, 
dated April 30, 2012.

(d) Subject

    Joint Aircraft System Component (JASC)/Air Transport Association 
(ATA) of America Code 21; Air Conditioning.

(e) Unsafe Condition

    This AD was prompted by the report of a flightcrew not receiving 
an aural warning during a lack of cabin pressurization event. The 
failure of the altitude pressure switch prevented the aural warning 
from sounding when the cabin altitude exceeded 10,000 feet. We are 
issuing this AD to prevent the loss of cabin altitude warning, which 
could delay flightcrew recognition of a lack of cabin 
pressurization, and could result in incapacitation of the flightcrew 
due to hypoxia (a lack of oxygen in the body), and consequent loss 
of control of the airplane.

(f) Compliance

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

(g) Installation

    Within 72 months after the effective date of this AD, install a 
redundant cabin altitude pressure switch, replace the aural warning 
module (AWM) with a new or reworked AWM, and change certain wire 
bundles or connect certain capped and stowed wires, as applicable, 
in accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-21-1164, Revision 1, dated May 17, 
2012 (for Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes); or Boeing Special Attention Service Bulletin 737-21-
1165, Revision 1, dated July 16, 2010, as revised by Boeing Special 
Attention Service Bulletin 737-21-1165, Revision 2, dated April 30, 
2012 (for Model 737-600, -700, -700C, -800, -900, and -900ER series 
airplanes).

(h) Concurrent Actions

    For airplanes identified in Boeing Alert Service Bulletin 737-
31A1325, dated January 11, 2010 (for Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes); and Boeing Alert Service 
Bulletin 737-31A1332, Revision 3, dated March 28, 2012 (for Model 
737-600, -700, -700C, -800, -900, and -900ER series airplanes): 
Before or concurrently with accomplishment of the actions specified 
in paragraph (g) of this AD, as applicable, modify the instrument 
panels, install light assemblies, modify the wire bundles, and 
install a new circuit breaker, in accordance with the Accomplishment 
Instructions of Boeing Alert Service Bulletin 737-31A1325, dated 
January 11, 2010 (for Model 737-100, -200, -200C, -300, -400, and -
500 series airplanes); or Boeing Alert Service Bulletin 737-31A1332, 
Revision 3, dated March 28, 2012 (for Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes).

(i) Credit for Previous Actions

    (1) This paragraph provides credit for the actions required by 
paragraph (h) of this AD, if those actions were performed before the 
effective date of this AD using Boeing Special Attention Service 
Bulletin 737-21-1165, Revision 1, dated July 16, 2010.

[[Page 60301]]

    (2) For Group 1 airplanes identified in Boeing Alert Service 
Bulletin 737-31A1332, Revision 1, dated June 24, 2010; except Groups 
24, 25, and 27 through 33 airplanes identified in Boeing Alert 
Service Bulletin 737-31A1332, Revision 3, dated March 28, 2012: This 
paragraph provides credit for the corresponding actions required by 
paragraph (h) of this AD, if those actions were performed before the 
effective date of this AD, using Boeing Alert Service Bulletin 737-
31A1332, Revision 1, dated June 24, 2010, which is not incorporated 
by reference.
    (3) For airplanes identified in Boeing Alert Service Bulletin 
737-31A1332, Revision 2, dated August 18, 2011; except airplanes 
identified in paragraph (i)(4) of this AD, and Groups 24, 25, and 27 
through 33 airplanes identified in Boeing Alert Service Bulletin 
737-31A1332, Revision 3, dated March 28, 2012: This paragraph 
provides credit for the corresponding actions required by paragraph 
(h) of this AD, if those actions were performed before the effective 
date of this AD using Boeing Alert Service Bulletin 737-31A1332, 
Revision 2, dated August 18, 2011.
    (4) For Group 21, Configuration 2 airplanes identified in Boeing 
Alert Service Bulletin 737-31A1332, Revision 3, dated March 28, 
2012: This paragraph provides credit for the corresponding actions 
required by paragraph (h) of this AD, if those actions were 
performed before the effective date of this AD using Boeing Alert 
Service Bulletin 737-31A1332, Revision 2, dated August 18, 2011; and 
provided that those actions in Boeing Service Bulletin 737-21-1171, 
dated February 12, 2009, were accomplished prior to or concurrently 
with the actions in Boeing Alert Service Bulletin 737-31A1332, 
Revision 2, dated August 18, 2011.

(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 Seattle ACO, send it to 
the attention of the person identified in the Related Information 
section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov.
    (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.

(k) Related Information

    For more information about this AD, contact Francis Smith, 
Aerospace Engineer, Cabin Safety and Environmental Systems Branch, 
ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind 
Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-6596; 
fax: (425) 917-6590; email: Francis.Smith@faa.gov.

(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 737-21-1164, 
Revision 1, dated May 17, 2012.
    (ii) Boeing Special Attention Service Bulletin 737-21-1165, 
Revision 1, dated July 16, 2010.
    (iii) Boeing Special Attention Service Bulletin 737-21-1165, 
Revision 2, dated April 30, 2012.
    (iv) Boeing Alert Service Bulletin 737-31A1325, dated January 
11, 2010.
    (v) Boeing Alert Service Bulletin 737-31A1332, Revision 1, dated 
June 24, 2010.
    (vi) Boeing Alert Service Bulletin 737-31A1332, Revision 2, 
dated August 18, 2011.
    (vii) Boeing Alert Service Bulletin 737-31A1332, Revision 3, 
dated March 28, 2012.
    (3) For The Boeing Company 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 review copies of the service information at the FAA, 
Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. 
For information on the availability of this material at the FAA, 
call 425-227-1221.
    (5) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at an NARA facility, call 202-741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    Issued in Renton, Washington, on September 19, 2012.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2012-23800 Filed 10-2-12; 8:45 am]
BILLING CODE 4910-13-P