
[Federal Register Volume 76, Number 251 (Friday, December 30, 2011)]
[Proposed Rules]
[Pages 82207-82210]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-33575]


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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]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company 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 airplanes. This proposed AD would incorporate 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 aural warning module (AWM) with a new or 
reworked AWM, changing certain wire bundles, and connecting certain 
previously capped and stowed wires, as necessary. This proposed AD, for 
certain airplanes, would also require modifying the instrument panels, 
installing light assemblies, modifying the wire bundles, and installing 
a new circuit breaker, as necessary. This proposed AD was prompted by a 
report of a lack of cabin pressurization event caused by the flightcrew 
not receiving an aural warning because of the failure of the cabin 
altitude pressure switch. We are proposing this AD to prevent failure 
of the flightcrew to recognize and react to a lack of cabin 
pressurization, which could result in incapacitation of the flightcrew 
due to hypoxia (lack of oxygen in the body), and consequent loss of 
control of the airplane.

DATES: We must receive comments on this proposed AD by February 13, 
2012.

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: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For Boeing 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; email 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com. For BAE 
Systems service information identified in this proposed AD, contact BAE 
Systems, Attention: Commercial Product Support, 600 Main Street, Room 
S18C, Johnson City, NY 13790-1806; telephone (607) 770-3084; fax (607) 
770-3015; email CS-Customer.Service@baesystems.com; Internet http://www.baesystems-ps.com/customersupport. 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 proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Office (phone: (800) 647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Jeffrey Palmer, 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) 917-6481; fax: (425) 917-6590; email: 
jeffrey.palmer@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send any written relevant data, views, or 
arguments about this proposal. Send your comments to an address listed 
under the ADDRESSES section. Include ``Docket No. FAA-2011-1411; 
Directorate Identifier 2011-NM-074-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 a report from an operator of an event in which the 
flightcrew was not aware of cabin depressurization. The flightcrew also 
were not aware that passenger oxygen masks had deployed until they were 
notified by a member of the cabin crew. Further investigations revealed 
that the flightcrew did not receive an aural warning because of the 
failure of the cabin altitude pressure switch at 10,000 feet. This 
condition, if not corrected, could result in failure of the flightcrew 
to recognize and react to a lack of cabin pressurization, which could 
result in incapacitation of the flightcrew due to hypoxia (lack of 
oxygen in the body), and consequent loss of control of the airplane.

Relevant Service Information

    We reviewed the following service information:

[[Page 82208]]

     Boeing Special Attention Service Bulletin 737-21-1164, 
dated February 10, 2011 (for Model 737-100, -200, -200C, -300, -400, 
and -500 series airplanes); and
     Boeing Special Attention Service Bulletin 737-21-1165, 
Revision 1, dated July 16, 2010 (for Model 737-600, -700, -700C, -800, 
-900, and -900ER series airplanes).
    The service information describes procedures for installing a 
redundant switch of the cabin altitude pressure, replacing the AWM with 
a new or reworked AWM, changing certain wire bundles, and connecting 
certain capped and stowed wires, as necessary.
    The service information refers to BAE Systems Service Bulletin 69-
78214-31-03, dated January 15, 2009, for guidance on reworking the AWM.
    Boeing Special Attention Service Bulletin 737-21-1164, dated 
February 10, 2011, specifies the concurrent accomplishment of the 
actions specified in Boeing Alert Service Bulletin 737-31A1325, dated 
January 11, 2010 (for Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes). Boeing Special Attention Service Bulletin 737-21-
1165, Revision 1, dated July 16, 2010, specifies the concurrent 
accomplishment of the actions specified in Boeing Alert Service 
Bulletin 737-31A1332, Revision 1, dated June 24, 2010 (for Model 737-
600, -700, -700C, -800, -900, and -900ER series airplanes).
    For certain airplane configurations, Boeing Alert Service Bulletin 
737-31A1325, dated January 11, 2010; and Boeing Alert Service Bulletin 
737-31A1332, Revision 1, dated June 24, 2010; describe procedures for 
modifying the instrument panels, installing light assemblies, modifying 
the wire bundles, and installing a new circuit breaker, as necessary. 
We have also received Boeing Alert Service Bulletin 737-31A1332, 
Revision 2, dated August 18, 2011 (for Model 737-600, -700, -700C, -
800, -900, and -900ER series airplanes), which added airplanes to the 
effectivity.
    Boeing Alert Service Bulletin 737-31A1332, Revision 2, dated August 
18, 2011, refers to BAE Systems Service Bulletins 233A2221-31-01, 
Revision 1, dated March 10, 2011; 233A2221-31-02, dated April 16, 2009; 
233A2221-31-03, Revision 1, dated March 10, 2011; 233A2221-31-05, 
Revision 1, dated March 10, 2011; 233A2222-31-01, Revision 1, dated 
March 10, 2011; 233A2222-31-02, Revision 1, dated March 10, 2011; 
233A2222-31-03, Revision 1, dated March 10, 2011; 233A2222-31-05, 
Revision 1, dated March 3, 2011; 233A3213-21-01, dated August 12, 2010; 
and 69-37319-31-05, dated August 26, 2010; as additional sources of 
guidance for modifying the instrument panels and installing the light 
assemblies.

Other Relevant Rulemaking

    On January 25, 2011, the FAA issued AD 2011-03-14, Amendment 39-
16598 (76 FR 6529, February 7, 2011), for Model 737-100, -200, -200C, -
300, -400, and -500 series airplanes, which currently requires 
installing two warning level indicator lights on the P2-2 center 
instrument panel in the flight compartment, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
31A1325, dated January 11, 2010.
    In addition, on March 14, 2011, the FAA issued Notice of Proposed 
Rulemaking (NPRM) FAA-2011-0258 (76 FR 16579, March 24, 2011), for 
Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, 
which currently proposes installing two warning level indicator lights 
on each of the P1-3 and P3-1 instrument panels in the flight 
compartment, in accordance with the Accomplishment Instructions of 
Boeing Alert Service Bulletin 737-31A1332, Revision 1, dated June 24, 
2010. We are considering revising NPRM FAA-2011-0258 to refer to Boeing 
Alert Service Bulletin 737-31A1332, Revision 2, dated August 18, 2011.
    AD 2011-03-14, Amendment 39-16598 (76 FR 6529, February 7, 2011), 
and NPRM FAA-2011-0258 (76 FR 16579, March 24, 2011), were prompted by 
a design change in the cabin altitude warning system. The actions 
required by that AD and proposed by that NPRM are intended to prevent 
failure of the flightcrew to recognize and react to a lack of cabin 
pressurization, which could result in incapacitation of the flightcrew 
due to hypoxia (lack of oxygen in the body), and consequent loss of 
control of the airplane.

FAA's Determination

    We are proposing this AD because we evaluated all the relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the same type design.

Proposed AD Requirements

    This proposed AD would require accomplishing the actions specified 
in the service information described previously.

Costs of Compliance

    We estimate that this proposed AD affects 1,405 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
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            Action                  Labor cost       Parts cost     Cost per product    Cost on U.S. operators
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Install a redundant switch of   Up to 31                   $4,082  Up to $6,717.....  Up to $9,437,385.
 the cabin altitude pressure,    work[dash]hours
 replace the AWM with a new or   x $85 per hour =
 reworked AWM, change certain    up to $2,635.
 wire bundles, and connect
 certain capped and stowed
 wires.
Modify the instrument panels,   Up to 84                    5,292  Up to 12,432.....  Up to $17,466,960.
 install light assemblies,       work[dash]hours
 modify the wire bundles, and    x $85 per hour =
 install a new circuit breaker.  up to $7,140.
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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

[[Page 82209]]

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),
    (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.

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 
airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2011-1411; Directorate Identifier 
2011-NM-074-AD.

(a) Comments Due Date

    We must receive comments by February 13, 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, dated February 10, 2011.
    (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.

(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 lack of cabin 
pressurization event caused by the flightcrew not receiving an aural 
warning because of the failure of the cabin altitude pressure 
switch. We are issuing this AD to prevent failure of the flightcrew 
to recognize and react to a lack of cabin pressurization, which 
could result in incapacitation of the flightcrew due to hypoxia 
(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 switch of the cabin altitude pressure, replace the aural 
warning module (AWM) with a new or reworked AWM, change certain wire 
bundles, and connect certain capped and stowed wires, as applicable, 
in accordance with the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-21-1164, dated February 10, 2011 (for 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes); 
and Boeing Special Attention Service Bulletin 737-21-1165, Revision 
1, dated July 16, 2010 (for Model 737-600, -700, -700C, -800, -900, 
and -900ER series airplanes).

    Note 1:  Additional guidance on reworking the AWM can be found 
in BAE Systems Service Bulletin 69-78214-31-03, dated January 15, 
2009.

(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 2, dated August 18, 2011 (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); and Boeing Alert Service Bulletin 737-
31A1332, Revision 2, dated August 18, 2011 (for Model 737-600, -700, 
-700C, -800, -900, and -900ER series airplanes).

    Note 2: Boeing Alert Service Bulletin 737-31A1332, Revision 2, 
dated August 18, 2011, refers to BAE Systems Service Bulletins 
233A2221-31-01, Revision 1, dated March 10, 2011; 233A2221-31-02, 
dated April 16, 2009; 233A2221-31-03, Revision 1, dated March 10, 
2011; 233A2221-31-05, Revision 1, dated March 10, 2011; 233A2222-31-
01, Revision 1, dated March 10, 2011; 233A2222-31-02, Revision 1, 
dated March 10, 2011; 233A2222-31-03, Revision 1, dated March 10, 
2011; 233A2222-31-05, Revision 1, dated March 3, 2011; 233A3213-21-
01, dated August 12, 2010; and 69-37319-31-05, dated August 26, 
2010; as additional sources of guidance for modifying the instrument 
panels and installing the light assemblies.


    Note 3: AD 2011-03-14, Amendment 39-16598 (76 FR 6529, February 
7, 2011), requires accomplishing the actions specified in Boeing 
Alert Service Bulletin 737-31A1325, dated January 11, 2010 (for 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes). 
Notice of Proposed Rulemaking FAA-2011-0258 (76 FR 16579, March 24, 
2011), is proposing to require Boeing Alert Service Bulletin 737-
31A1332, Revision 1, dated June 24, 2010 (for Model 737-600, -700, -
700C, -800, -900, and -900ER series airplanes). We are considering 
revising NPRM FAA-2011-0258 to refer to Boeing Alert Service 
Bulletin 737-31A1332, Revision 2, dated August 18, 2011.

(i) Credit for Actions Accomplished in Accordance With Previous Service 
Information

    Actions accomplished before the effective date of this AD 
according to Boeing Alert Service Bulletin 737-31A1332, Revision 1, 
dated June 24, 2010, are considered acceptable for compliance with 
the corresponding action specified 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 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.

(k) Related Information

    (1) For more information about this AD, contact Jeffrey Palmer, 
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) 917-6481; 
fax: (425) 917-6590; email: jeffrey.palmer@faa.gov.
    (2) For Boeing service information identified in this AD, 
contact Boeing Commercial Airplanes, Attention: Data & Services 
Management, P.O. Box 3707, MC

[[Page 82210]]

2H-65, Seattle, Washington 98124-2207; telephone (206) 544-5000, 
extension 1; fax (206) 766-5680; email me.boecom@boeing.com; 
Internet https://www.myboeingfleet.com. For BAE Systems service 
information identified in this AD, contact BAE Systems, Attention: 
Commercial Product Support, 600 Main Street, Room S18C, Johnson 
City, NY 13790-1806; telephone (607) 770-3084; fax (607) 770-3015; 
email CS-Customer.Service@baesystems.com; Internet http://www.baesystems-ps.com/customersupport. 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.

    Issued in Renton, Washington, on December 16, 2011.
Michael Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-33575 Filed 12-29-11; 8:45 am]
BILLING CODE 4910-13-P


