
[Federal Register Volume 76, Number 215 (Monday, November 7, 2011)]
[Proposed Rules]
[Pages 68666-68668]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-28758]



[[Page 68666]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-1171; Directorate Identifier 2011-NM-101-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 The Boeing Company Model 737-100, -200, -200C, and -300 series 
airplanes. This proposed AD was prompted by a report from the airplane 
manufacturer that airplanes were assembled with air distribution ducts 
in the environmental control system (ECS) wrapped with Boeing Material 
Specification (BMS) 8-39 or Aeronautical Materials Specifications (AMS) 
3570 polyurethane foam insulation, a material with fire-retardant 
properties that deteriorate with age. This proposed AD would require 
reworking certain air distribution ducts in the ECS. We are proposing 
this AD to prevent ignition of the BMS 8-39 or AMS 3570 polyurethane 
foam insulation on the duct assemblies of the ECS due to a potential 
electrical arc, which could start a small fire and lead to a larger 
fire that may spread throughout the airplane through the ECS.

DATES: We must receive comments on this proposed AD by December 22, 
2011.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, 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 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. 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: Kimberly A. DeVoe, 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) 917-6495; fax: (425) 917-6590; email: 
Kimberly.Devoe@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-2011-1171; 
Directorate Identifier 2011-NM-101-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 reports of duct assemblies in the ECS with burned 
BMS 8-39 polyurethane foam insulation on two Model 767-200 series 
airplanes. The airplane manufacturer has also notified us that certain 
Model 737-100, -200, -200C, and -300 series airplanes were assembled 
with duct assemblies in the ECS wrapped with BMS 8-39 or AMS 3570 
polyurethane foam insulation. The fire-retardant properties of BMS 8-39 
and AMS 3570 polyurethane foam insulation deteriorate with age. This, 
along with dust, dirt, and other carbon particulate contamination of 
the insulation on the ducts, adds an available fuel source for a 
potential fire. Once ignited, the foam insulation emits noxious smoke, 
does not self-extinguish, and drips droplets of liquefied polyurethane, 
which can further propagate a fire. Because the insulation is wrapped 
around the duct assemblies, which are located throughout the airplane, 
if the insulation is ignited a fire could potentially travel along the 
ducts and spread throughout the airplane. This condition, if not 
corrected, could result in ignition of the BMS 8-39 or AMS 3570 
polyurethane foam insulation on the duct assemblies of the ECS due to a 
potential electrical arc, which could start a small fire and lead to a 
larger fire that may spread throughout the airplane through the ECS.

Other Relevant Rulemaking

    On January 14, 2008, we issued AD 2008-02-16, Amendment 39-15346 
(73 FR 4061, January 24, 2008), applicable to certain Model 767-200 and 
767-300 series airplanes.
    On June 17, 2010, we issued AD 2010-14-01, Amendment 39-16344 (75 
FR 38007, July 1, 2010), applicable to certain Model 747-100, 747-100B, 
747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400F, 
747SR, and 747SP series airplanes.
    AD 2008-02-16, Amendment 39-15346 (73 FR 4061, January 24, 2008), 
and AD 2010-14-01, Amendment 39-16344 (75 FR 38007, July 1, 2010), 
require reworking certain duct assemblies in the ECS. These ADs 
resulted from reports of duct assemblies in the ECS with burned BMS 8-
39 polyurethane foam insulation. These ADs also resulted from reports 
from the airplane manufacturer that airplanes were assembled with duct 
assemblies in the ECS wrapped with BMS 8-39 polyurethane foam 
insulation, a material with fire-retardant properties that deteriorate 
with age. We issued these ADs to prevent a potential electrical arc 
from igniting the BMS 8-39 polyurethane foam insulation on the duct 
assemblies of the ECS, which could propagate a small fire and lead to a 
larger fire that might spread throughout the airplane through the ECS.

[[Page 68667]]

Relevant Service Information

    We reviewed Boeing Service Bulletin 737-21A1132, Revision 3, dated 
February 16, 2011. This service bulletin describes procedures for 
reworking and part-marking the following affected duct assemblies ECS 
systems. The rework includes doing a pressure and leak test following 
installation of the new insulation.
     Captain's outlet air distribution ducts
     Control cabin air distribution ducts
     Distribution manifold
     Passenger air distribution gasper air ducts

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, except as discussed 
under ``Differences Between the Proposed AD and the Service 
Information.''

Differences Between the Proposed AD and the Service Information

    Boeing Service Bulletin 737-21A1132, Revision 3, dated February 16, 
2011, recommends reworking the affected duct assemblies ``during the 
next heavy maintenance check, within 24,000 flight-hours from the date 
on this service bulletin.'' This proposed AD would require operators to 
rework the affected duct assemblies within 72 months after the 
effective date of the AD. In developing the compliance time for this 
action, we considered the degree of urgency associated with addressing 
the subject unsafe condition. We also considered the availability of 
required parts and the practical aspect of reworking the affected duct 
assemblies within an interval that parallels normal scheduled 
maintenance for most affected operators. The average heavy maintenance 
schedule for the affected fleet is between 60 and 72 months; therefore, 
the proposed compliance time of 72 months is equivalent to the 
recommended compliance time of ``during the next heavy maintenance 
check, within 24,000 flight-hours,'' and it represents an appropriate 
interval in which an ample number of required parts will be available 
to modify the affected fleet without adversely affecting the safety of 
these airplanes. This difference has been coordinated with the Boeing 
Company.

Costs of Compliance

    We estimate that this proposed AD affects 292 airplanes of U.S. 
registry.
    We estimate the following costs to comply with this proposed AD:

                                                 Estimated Costs
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
              Action                    Labor cost           Parts cost      Cost per product      operators
----------------------------------------------------------------------------------------------------------------
Duct assembly rework/part marking  250 work-hours x $85            $3,545            $24,795         $7,240,140
                                    per hour = $21,250.
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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),
    (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-2011-1171; Directorate Identifier 
2011-NM-101-AD.

(a) Comments Due Date

    We must receive comments by December 22, 2011.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to The Boeing Company Model 737-100, -200, -
200C, and -300 series airplanes, certificated in any category; as 
identified in Boeing Service Bulletin 737-21A1132, Revision 3, dated 
February 16, 2011.

(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 a report from the airplane manufacturer 
that airplanes were assembled with air distribution ducts in the 
environmental control system (ECS) wrapped with Boeing Material 
Specification (BMS) 8-39 or Aeronautical Materials Specifications 
(AMS) 3570 polyurethane foam insulation, a material with fire 
retardant properties that

[[Page 68668]]

deteriorate with age. We are issuing this AD to prevent ignition of 
the BMS 8-39 or AMS 3570 polyurethane foam insulation on the duct 
assemblies of the ECS due to a potential electrical arc, which could 
start a small fire and lead to a larger fire that may spread 
throughout the airplane through the ECS.

(f) Compliance

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

(g) Air Distribution Duct Rework

    Within 72 months after the effective date of this AD, rework the 
applicable duct assemblies in the ECS specified in and in accordance 
with the Accomplishment Instructions and Appendix A of Boeing 
Service Bulletin 737-21A1132, Revision 3, dated February 16, 2011.

    Note 1: The service bulletin accomplishment instructions might 
refer to other procedures. When the words ``refer to'' are used and 
the operator has an accepted alternative procedure, the accepted 
alternative procedure can be used to comply with the AD. When the 
words ``in accordance with'' are included in the instruction, the 
procedure in the design approval holder document must be used to 
comply with the AD.

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

    Reworking the applicable duct assemblies in the ECS in 
accordance with the Accomplishment Instructions and Appendix A of 
Boeing Service Bulletin 737-21A1132, Revision 2, dated June 13, 
2007, before the effective date of this AD is acceptable for 
compliance with the corresponding actions required by paragraph (g) 
of this AD.

(i) Parts Installation

    As of the effective date of this AD, no person may install an 
ECS duct assembly with BMS 8-39 or AMS 3570 polyurethane foam 
insulation on any airplane.

(j) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Seattle Aircraft Certification Office (ACO), 
FAA, has the authority to approve AMOCs for this AD, if requested 
using the procedures found in 14 CFR 39.19. In accordance with 14 
CFR 39.19, send your request to your principal inspector or local 
Flight Standards District Office, as appropriate. If sending 
information directly to the manager of the ACO, send it to the 
attention of the person identified in the Related Information 
section of this AD. Information may be emailed to: 9-ANM&-Seattle-ACO-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 Kimberly A. 
DeVoe, 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-
6495; fax: (425) 917-6590; email: Kimberly.Devoe@faa.gov.
    (2) 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; phone: 
(206) 544-5000, extension 1; fax: (206) 766-5680; email: 
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.

    Issued in Renton, Washington, on October 26, 2011.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-28758 Filed 11-4-11; 8:45 am]
BILLING CODE 4910-13-P


