
[Federal Register: August 11, 2010 (Volume 75, Number 154)]
[Proposed Rules]               
[Page 48620-48623]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr11au10-21]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0761; Directorate Identifier 2010-NM-069-AD]
RIN 2120-AA64

 
Airworthiness Directives; The Boeing Company Model 737-100, -200, 
-200C, -300, -400, and -500 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 737-100, -200, -200C, -300, -400, and -500 series 
airplanes. This proposed AD would require installing two warning level 
indicator lights on the P2-2 center instrument panel in the flight 
compartment for certain airplanes. For a certain other airplane, this 
proposed AD would require activating the cabin altitude warning and 
takeoff configuration warning lights. For all airplanes, this proposed 
AD also would require revising the airplane flight manual to remove 
certain requirements included by previous AD actions, to require new 
pressure altitude limitations for certain airplanes, and to advise the 
flightcrew of the following changes: revised emergency procedures to 
use when a cabin altitude warning or rapid depressurization occurs, and 
revised cabin pressurization procedures for normal operations. This 
proposed AD results from a design change in the cabin altitude warning 
system that would address the identified unsafe condition. We are 
proposing this AD to prevent failure of the flightcrew to recognize and 
react to a valid cabin altitude warning horn, which could result in 
incapacitation of the flightcrew due to hypoxia (lack of oxygen in 
body), and consequent loss of control of the airplane.

DATES: We must receive comments on this proposed AD by September 27, 
2010.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the instructions for submitting comments.
     Fax: 202-493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    For service information identified in this proposed AD, contact 
Boeing Commercial Airplanes, Attention: Data & Services Management, 
P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
Internet https://www.myboeingfleet.com. You may review copies of the 
referenced service information at the FAA, Transport Airplane 
Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information 
on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://
www.regulations.gov; or in person at the Docket Management Facility 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD 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.

[[Page 48621]]


FOR FURTHER INFORMATION CONTACT: Jeffrey W. Palmer, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-
3356; telephone (425) 917-6472; 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-2010-0761; 
Directorate Identifier 2010-NM-069-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

    The Model 737 cabin altitude warning is an intermittent horn that 
sounds when cabin altitude exceeds 10,000 feet. The same intermittent 
warning horn sound is utilized by the takeoff configuration warning 
system (TCWS) to warn of unsafe airplane configuration for takeoff. The 
TCWS warning functionality is inhibited by air/ground logic when the 
airplane is in flight. However, the Model 737 cabin altitude warning 
system design does not currently incorporate a dedicated means of 
positively identifying the warning horn as a cabin altitude warning or 
a takeoff configuration warning. There are approximately 25 known 
instances where flightcrews have misinterpreted a valid cabin altitude 
warning as a takeoff configuration warning.
    Failure of the flightcrew to recognize and react to a valid cabin 
altitude warning horn could result in incapacitation of the flightcrew 
due to hypoxia (lack of oxygen in body), and consequent loss of control 
of the airplane. To address this unsafe condition, we issued the 
following ADs.
    On November 7, 2003, we issued related AD 2003-03-15 R1, Amendment 
39-13366 (68 FR 64802, November 17, 2003), for various The Boeing 
Company and McDonnell Douglas Corporation transport category airplanes. 
That AD requires revising the airplane flight manual (AFM) to advise 
the flightcrew to don oxygen masks as a first and immediate step when 
the cabin altitude warning occurs. We issued that AD to prevent 
incapacitation of the flightcrew due to lack of oxygen, which could 
result in loss of control of the airplane.
    On June 15, 2006, we issued related AD 2006-13-13, Amendment 39-
14666 (71 FR 35781, June 22, 2006). (A correction of that AD was 
published in the Federal Register on July 3, 2006 (71 FR 37980).) That 
AD applies to all Model 737 airplanes. That AD requires revising the 
AFM to advise the flightcrew of improved procedures for pre-flight 
setup of the cabin pressurization system, as well as improved 
procedures for interpreting and responding to the cabin altitude/
configuration warning horn. That AD resulted from reports that 
airplanes had failed to pressurize, and that the flightcrews failed to 
react properly to the cabin altitude warning horn. We issued that AD to 
prevent failure of the airplane to pressurize and subsequent failure of 
the flightcrew to recognize and react to a valid cabin altitude warning 
horn, which could result in incapacitation of the flightcrew due to 
hypoxia (lack of oxygen in body) and consequent loss of airplane 
control.
    On October 24, 2008, we issued related AD 2008-23-07, Amendment 39-
15728 (73 FR 66512, November 10, 2008), for all Model 737 airplanes. 
That AD requires revising the AFM to include a new flightcrew briefing 
that must be done before the first flight of the day and following any 
change in flightcrew members, and to advise the flightcrew of this 
additional briefing. That AD resulted from continuing reports that 
flightcrews have failed to recognize and react properly to the cabin 
altitude warning horn. We issued that AD to prevent failure of the 
flightcrew to recognize and react properly to a valid cabin altitude 
warning horn, which could result in incapacitation of the flightcrew 
due to hypoxia (lack of oxygen in body) and consequent loss of airplane 
control.
    The preambles to AD 2006-13-13 and AD 2008-23-07 explain that the 
revisions to the AFM required by those ADs are considered to be interim 
action. The manufacturer had advised us that it was developing a design 
change in the cabin altitude warning system that would address the 
identified unsafe condition(s), and that once this design change was 
developed, approved, and available, the FAA might consider additional 
rulemaking. The manufacturer now has developed such a modification, and 
we have determined that further rulemaking is necessary; this proposed 
AD follows from that determination. We can better ensure long-term 
continued operational safety by modifications or design changes to 
remove the source of the problem, rather than by AFM revisions alone.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-31A1325, dated 
January 11, 2010 (for Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes). This service bulletin describes procedures for 
installing two warning level indicator lights on the P2-2 center 
instrument panel in the flight compartment. This installation includes 
changing three wire bundles.
    We have also reviewed Boeing Alert Service Bulletin 737-31A1398, 
dated January 7, 2010 (for Model 737-400 series airplane, variable 
number PW234). This service bulletin describes procedures for 
activating the cabin altitude warning and takeoff configuration warning 
lights. The activation includes changing the wiring in the W066 wire 
bundle and removing the INOP markers from the cabin altitude warning 
and takeoff configuration warning lights.

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 the same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously. The proposed AD would 
also require revising the AFM to remove certain requirements included 
by previous AD actions, to require new pressure altitude limitations 
for certain airplanes, and to advise the flightcrew of the following 
changes: revised emergency procedures to use when a cabin altitude 
warning or rapid depressurization occurs, and revised cabin 
pressurization procedures for normal operations.

Costs of Compliance

    We estimate that this proposed AD would affect 741 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

[[Page 48622]]



                                                                 Table--Estimated Costs
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                            Number  of
                                                                          Average  labor                     Cost per          U.S.-
                         Action                             Work hours    rate  per hour       Parts          product       registered      Fleet cost
                                                                                                                             airplanes
--------------------------------------------------------------------------------------------------------------------------------------------------------
Installation of warning indicator lights................              20             $85          $2,738          $4,438             740      $3,284,120
Activation of the cabin altitude warning system/takeoff                1              85               0              85               1              85
 configuration warning lights...........................
AFM revision............................................               1              85               0              85             741          62,985
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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-2010-0761; Directorate Identifier 
2010-NM-069-AD.

Comments Due Date

    (a) We must receive comments by September 27, 2010.

Affected ADs

    (b) This AD affects the ADs identified in paragraphs (b)(1), 
(b)(2), and (b)(3) of this AD. This AD does not supersede the 
requirements of these ADs.
    (1) AD 2008-23-07, Amendment 39-15728.
    (2) AD 2006-13-13, Amendment 39-14666.
    (3) AD 2003-03-15 R1, Amendment 39-13366.

Applicability

    (c) This AD applies to the airplanes, certificated in any 
category, identified in paragraphs (c)(1) and (c)(2) of this AD.
    (1) The Boeing Company Model 737-100, -200, -200C, -300, -400, 
and -500 series airplanes identified in Boeing Alert Service 
Bulletin 737-31A1325, dated January 11, 2010.
    (2) The Boeing Company Model 737-400 series airplanes identified 
in Boeing Alert Service Bulletin 737-31A1398, dated January 7, 2010.

Subject

    (d) Air Transport Association (ATA) of America Code 31: 
Instruments.

Unsafe Condition

    (e) This AD results from a design change in the cabin altitude 
warning system that would address the identified unsafe condition. 
The Federal Aviation Administration is issuing this AD to prevent 
failure of the flightcrew to recognize and react properly to a valid 
cabin altitude warning horn, which could result in incapacitation of 
the flightcrew due to hypoxia (lack of oxygen in body) and 
consequent loss of airplane control.

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.

Installation of Warning Indicator Lights

    (g) For airplanes identified in Boeing Alert Service Bulletin 
737-31A1325, dated January 11, 2010: Within 36 months after the 
effective date of this AD, install 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.

Activation of Warning Indicator Lights

    (h) For airplanes identified in Boeing Alert Service Bulletin 
737-31A1398, dated January 7, 2010: Within 36 months after the 
effective date of this AD, activate the cabin altitude warning and 
takeoff configuration warning lights, in accordance with the 
Accomplishment Instructions of Boeing Alert Service Bulletin 737-
31A1398, dated January 7, 2010.

Airplane Flight Manual (AFM) Revisions

    (i) Before further flight after doing the installation or 
activation of the warning lights required by paragraph (g) or (h) of 
this AD, do the actions specified in paragraphs (i)(1), (i)(2), and 
(i)(3) of this AD.
    (1) Revise the Limitations Section of the applicable Boeing 737 
AFM by doing the actions specified in paragraphs (i)(1)(i) and 
(i)(1)(ii) of this AD.
    (i) Delete the ``CABIN ALTITUDE WARNING TAKEOFF BRIEFING'' added 
by AD 2008-23-07.
    (ii) Add the following statement. This may be done by inserting 
a copy of this AD into the applicable AFM.
    ``For airplanes approved for maximum takeoff and landing 
altitudes above 8,400 feet pressure altitude, change the limitation 
for Maximum Takeoff and Landing pressure altitude as follows: With 
the CABIN ALTITUDE and TAKEOFF CONFIG lights installed and operative 
on those airplanes without the High Altitude Landing switch 
installed, maximum takeoff and landing altitude is limited to 9,000 
feet pressure altitude.''

[[Page 48623]]

    (2) Revise the Emergency Procedures Section of the applicable 
Boeing 737 AFM by doing the actions specified in paragraphs 
(i)(2)(i), (i)(2)(ii), (i)(2)(iii), and (i)(2)(iv) of this AD.
    (i) Delete the procedure ``WARNING HORN--CABIN ALTITUDE OR 
CONFIGURATION'' added by AD 2006-13-13.
    (ii) Delete the procedure entitled ``CABIN ALTITUDE WARNING OR 
RAPID DEPRESSURIZATION'' added by AD 2006-13-13.
    (iii) If the procedure entitled ``CABIN ALTITUDE (Airplanes with 
the CABIN ALTITUDE lights installed)'' is currently contained in the 
applicable Boeing 737 AFM, delete the procedure entitled ``CABIN 
ALTITUDE (Airplanes with the CABIN ALTITUDE lights installed).''
    (iv) Add the following statement. This may be done by inserting 
a copy of this AD into the applicable AFM.

``CABIN ALTITUDE WARNING OR RAPID DEPRESSURIZATION (required by 
this ad)

    Condition: The CABIN ALTITUDE warning light illuminates or the 
intermittent warning horn sounds in flight above 10,000 ft MSL.




RECALL:
    Oxygen Masks and Regulators............  On, 100%
    Crew Communications....................  Establish
REFERENCE:
    Pressurization Mode Selector...........  Manual
    Outflow Valve Switch...................  Close
    Passenger Oxygen (If Required).........  On
    Descent (If Required)..................  Initiate


    (3) Revise the Normal Procedures Section of the applicable 
Boeing 737 AFM by doing the actions specified in paragraphs 
(i)(3)(i) and (i)(3)(ii) of this AD.
    (i) Delete the ``CABIN ALTITUDE WARNING TAKEOFF BRIEFING'' 
procedure added by AD 2008-23-07.
    (ii) Add the following statement. This may be done by inserting 
a copy of this AD into the applicable AFM.
    ``For normal operations, the pressurization mode selector should 
be in AUTO prior to takeoff. (Required by this AD)''

    Note 1:  When statements identical to those specified in 
paragraphs (i)(1)(ii), (i)(2)(iv), and (i)(3)(ii) of this AD have 
been included in the general revisions of the AFM, the general 
revisions may be inserted into the AFM, and the copies of this AD 
may be removed from the AFM.

Terminating Action for Affected ADs

    (j) Accomplishment of the requirements of this AD terminates the 
specified requirements of the ADs identified in paragraphs (j)(1), 
(j)(2), and (j)(3) of this AD, for only the airplanes identified in 
paragraphs (c)(1) and (c)(2) of this AD.
    (1) AD 2008-23-07: All requirements of that AD.
    (2) AD 2006-13-13: All requirements of that AD.
    (3) AD 2003-03-15 R1: The requirements specified in paragraph 
(a), Table 2, and Figures 2 and 3 of that AD.

Special Flight Permit

    (k) Special flight permits, as described in Section 21.197 and 
Section 21.199 of the Federal Aviation Regulations (14 CFR 21.197 
and 21.199), are not allowed.

Alternative Methods of Compliance (AMOCs)

    (l)(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: Jeffrey W. Palmer, Aerospace Engineer, Systems and Equipment 
Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 
Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6472; fax (425) 917-6590. Information may be e-mailed to: 9-ANM-
Seattle-ACO-AMOC-Requests@faa.gov.
    (2) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Before using any approved AMOC on any airplane to which the AMOC 
applies, notify your principal maintenance inspector (PMI) or 
principal avionics inspector (PAI), as appropriate, or lacking a 
principal inspector, your local Flight Standards District Office. 
The AMOC approval letter must specifically reference this AD.

    Issued in Renton, Washington, on July 28, 2010.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-19834 Filed 8-10-10; 8:45 am]
BILLING CODE 4910-13-P

