Airworthiness Directives; Boeing Model 737 Airplanes

[Federal Register Volume 71, Number 120 (Thursday, June 22, 2006)]
[Rules and Regulations]
[Pages 35781-35783]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-5585]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-25102; Directorate Identifier 2006-NM-117-AD; 
Amendment 39-14666; AD 2006-13-13]
RIN 2120-AA64


Airworthiness Directives; Boeing Model 737 Airplanes

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for all 
Boeing Model 737 airplanes. This AD requires revising the airplane 
flight manual 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. This AD results from reports that airplanes 
have failed to pressurize, and that the flightcrews failed to react 
properly to the cabin altitude warning horn. We are issuing this 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.

DATES: This AD becomes effective July 7, 2006.
    We must receive comments on this AD by August 21, 2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this AD.
    <bullet> DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590.
    <bullet> Fax: (202) 493-2251.
    <bullet> Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Gregg Nesemeier, Aerospace Engineer, 
Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft 
Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98055-
4056; telephone (425) 917-6479; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    We have received a report indicating that during the investigation 
by the Air Accident Investigation and Aviation Safety Board of Greece 
into the August 14, 2005, Helios Airways accident near Athens, Greece, 
it was found that the Boeing Model 737-300 series airplane was not 
pressurized during the climb from the departure airport, and the 
flightcrew subsequently became incapacitated. It appears that the 
pressurization mode selector was improperly set for flight, and that 
the flightcrew subsequently misinterpreted the cabin altitude warning 
horn as a takeoff configuration warning horn. This misinterpretation 
may have occurred because the same warning horn provides both warning 
functions on Model 737 airplanes.
    In addition, the FAA has become aware of a number of other 
incidents involving Model 737 airplanes where the flightcrew reaction 
to a valid cabin altitude warning horn was delayed, either because the 
flightcrew misinterpreted the horn as a takeoff configuration warning 
horn, or because they did not immediately don their oxygen masks. Crew 
reaction may have been delayed because the cabin altitude warning 
system on Model 737 airplanes provides only the warning horn; no 
associated cabin altitude warning light is installed that activates 
concurrently with the warning horn.
    Failure of the airplane to pressurize and subsequent failure of the 
flightcrew to recognize and react to a valid cabin altitude warning 
horn, if not corrected, could result in incapacitation of the 
flightcrew due to hypoxia (lack of oxygen in body) and consequent loss 
of airplane control.

Related Rulemaking

    We have previously issued two ADs to address similar unsafe 
conditions.
    On December 22, 2003, we issued AD 2003-03-15 R1, amendment 39-
13366 (68 FR 64802, November 17, 2003), to require revising the AFM to 
advise the flightcrew to don oxygen masks as a first and immediate step 
when the cabin altitude warning occurs. That AD is applicable to 
various Boeing and McDonnell Douglas transport category airplanes, 
including Boeing Model 737-100, -200, -200C, -300, -400, and -500 
series airplanes.
    On July 14, 2003, we issued AD 2003-14-08, amendment 39-13227 (68 
FR 41519, July 7, 2003), to require revising the AFM to require the 
same actions on various Boeing transport category airplanes, including 
Boeing 737-600, -700, -700C, -800, and -900 series airplanes.
    In paragraph (a) of those ADs, a part of the revised text that we 
required to be placed in the AFMs of Model 737 airplanes reads ``If the 
cabin altitude warning horn sounds: * * *'' or ``Condition: The cabin 
altitude warning horn sounds: * * *'', as applicable. Boeing has 
advised us that in light of the information given in the Discussion 
section above, it has updated the AFM phrase to read ``If the 
intermittent cabin altitude/configuration warning horn sounds in 
flight: * * *'' We have approved this new phrase in the AD as 
acceptable for compliance with the requirements of paragraph (a) of ADs 
2003-14-08 and 2003-03-15 R1.

FAA's Determination and Requirements of This AD

    The unsafe condition described previously is likely to exist or 
develop on other airplanes of the same type design. For this reason, we 
are issuing this 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. This AD requires revising the 
airplane flight manual (AFM) to advise the flightcrew of

[[Page 35782]]

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.

Interim Action

    Revisions to the Emergency or Non-Normal Procedures sections of the 
AFM are considered to be interim action. The manufacturer has advised 
that it currently is developing a design change in the cabin altitude 
warning system that will address the unsafe condition addressed by this 
AD. Once this design change is developed, approved, and available, the 
FAA may consider additional rulemaking.

FAA's Determination of the Effective Date

    Since an unsafe condition exists that requires the immediate 
adoption of this AD, we have found that notice and opportunity for 
public comment before issuing this AD are impracticable, and that good 
cause exists to make this AD effective in less than 30 days.

Comments Invited

    This AD is a final rule that involves requirements that affect 
flight safety and was not preceded by notice and an opportunity for 
public comment; however, we invite you to submit any relevant written 
data, views, or arguments regarding this AD. Send your comments to an 
address listed in the ADDRESSES section. Include ``Docket No. FAA-2006-
25102; Directorate Identifier 2006-NM-117-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the AD that might 
suggest a need to modify it.
    We will post all comments we receive, without change, to http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this AD. Using the search function of that Web 
site, anyone can find and read the comments in any of our dockets, 
including the name of the individual who sent the comment (or signed 
the comment on behalf of an association, business, labor union, etc.). 
You may review the DOT's complete Privacy Act Statement in the Federal 
Register published on April 11, 2000 (65 FR 19477-78), or you may visit 
http://dms.dot.gov.

Examining the Docket

    You may examine the AD docket on the Internet at http://dms.dot.gov, or in person at the Docket Management Facility office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Management Facility office (telephone (800) 647-
5227) is located on the plaza level of the Nassif Building at the DOT 
street address stated in the ADDRESSES section. Comments will be 
available in the AD docket shortly after the Docket Management System 
receives them.

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 have determined that 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 the 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.
    We prepared a regulatory evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket. See the ADDRESSES 
section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

Adoption of the Amendment

0
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 Federal Aviation Administration (FAA) amends Sec.  39.13 by 
adding the following new airworthiness directive (AD):

2006-13-13 Boeing: Amendment 39-14666. Docket No. FAA-2006-25102; 
Directorate Identifier 2006-NM-117-AD.

Effective Date

    (a) This AD becomes effective July 7, 2006.

Affected ADs

    (b) This AD is related to paragraph (a) of AD 2003-03-15 R1, 
amendment 39-13366, and paragraph (a) of AD 2003-14-08, amendment 
39-13227. This AD does not supersede the requirements of AD 2003-03-
15 R1 or AD 2003-14-08.

Applicability

    (c) This AD applies to all Boeing Model 737-100, -200, -200C, -
300, -400, -500, -600, -700, -700C, -800 and -900 series airplanes, 
certificated in any category.

Unsafe Condition

    (d) This AD results from reports that airplanes have failed to 
pressurize, and that the flightcrews failed to react properly to the 
cabin altitude warning horn. We are issuing this 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.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within the compliance times specified, unless the 
actions have already been done.

Revising the Airplane Flight Manuals (AFMs)

    (f) Within 60 days after the effective date of this AD, revise 
the Cabin Pressurization procedures in the Normal Procedures section 
of the AFMs for Model 737-100, -200, -200C, -300, -400, -500, -600, 
-700, -700C, -800, and -900 series airplanes to include the 
following procedure:
    ``For normal operations, the pressurization mode selector should 
be in AUTO prior to takeoff.''
    (g) Within 60 days after the effective date of this AD, revise 
the Emergency Procedures section of the AFMs for Model 737-100, -
200, -200C, -300, -400, and -500 series

[[Page 35783]]

airplanes, or the Non-Normal Procedures section of the AFMs for 
Model 737-600, -700, -700C, -800, and -900 series airplanes, as 
applicable, to include the following procedure:

``Warning Horn--Cabin Altitude or Configuration Recall

    Condition: An intermittent or steady warning horn sounds:
    <bullet> In flight an intermittent horn indicates the cabin 
altitude is at or above 10,000 feet
    <bullet> On the ground an intermittent horn indicates an 
improper takeoff configuration when advancing thrust levers to 
takeoff thrust
    <bullet> In flight a steady horn indicates an improper landing 
configuration.
    If an intermittent horn sounds in flight:

 
 
 
Oxygen Masks and Regulators...............  on, 100%
Crew Communications.......................  Establish
Do the Cabin Altitude Warning or Rapid
 Depressurization checklist.
 

    If an intermittent horn sounds on the ground: Assure proper 
airplane takeoff configuration.
    If a steady horn sounds in flight: Assure proper airplane 
landing configuration.''

Optional Action for Certain Requirements of AD 2003-03-15 R1 and AD 
2003-14-08

    (h) For Model 737-100, -200, -200C, -300, -400, and -500 series 
airplanes: Using the phrase, ``If the intermittent cabin altitude/
configuration warning horn sounds in flight:'' in place of the 
phrase, ``If the cabin altitude warning horn sounds:'', in the 
revisions to the ``Cabin Altitude Warning or Rapid 
Depressurization'' procedure specified in Figures 2 and 3 of AD 
2003-03-15 R1, is acceptable for compliance with the requirements of 
paragraph (a) of AD 2003-03-15 R1. All other requirements of AD 
2003-03-15 R1 remain unchanged.
    (i) For Model 737-600, -700, -700C, -800, and -900 series 
airplanes: Using the phrase, ``If the intermittent cabin altitude/
configuration warning horn sounds in flight:'' in place of the 
phrase, ``Condition: The cabin altitude warning horn sounds:'', in 
the revisions to the ``Cabin Altitude Warning or Rapid 
Depressurization'' procedure specified in Figure 1 of AD 2003-14-08, 
is acceptable for compliance with the requirements of paragraph (a) 
of AD 2003-14-08. All other requirements of AD 2003-14-08 remain 
unchanged.

Alternative Method To Revising the AFM

    (j) The AFM revisions specified in paragraphs (f) and (g) of 
this AD may be done by inserting a copy of this AD into the AFM.
    (k) When statements identical to those specified in paragraphs 
(f) and (g) of this AD have been included in general revisions of 
the AFM, then the general revision(s) may be inserted into the AFM, 
and the copy of the AD may be removed from the applicable revised 
sections of the AFM.

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 in 
accordance with the procedures found in 14 CFR 39.19.
    (2) Before using any AMOC approved in accordance with Sec.  
39.19 on any airplane to which the AMOC applies, notify the 
appropriate principal inspector in the FAA Flight Standards 
Certificate Holding District Office.

Material Incorporated by Reference

    (m) None.

    Issued in Renton, Washington, on June 15, 2006.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 06-5585 Filed 6-21-06; 8:45 am]
BILLING CODE 4910-13-P

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