68666 Federal Register / Vol. 76, No. 215 / Monday, November 7, 2011 / Proposed Rules 

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). 

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 fireretardant 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. 


srobinson on DSK4SPTVN1PROD with PROPOSALS
Federal Register / Vol. 76, No. 215 / Monday, November 7, 2011 / Proposed Rules 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

Action Labor cost Parts cost Cost per product Cost on U.S. 

operators 

Duct assembly rework/part marking ......... 250 work-hours × $85 per hour = 

$21,250.

$3,545 $24,795 $7,240,140 

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. 

§ 39.13 [Amended] 

2. The FAA amends § 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 


srobinson on DSK4SPTVN1PROD with PROPOSALS
68668 Federal Register / Vol. 76, No. 215 / Monday, November 7, 2011 / Proposed Rules 

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 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2011–1169; Directorate 

Identifier 2010–NM–050–AD] 

RIN 2120–AA64 

Airworthiness Directives; Fokker 

Services B.V. Model F.28 Mark 0100 

Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: We propose to adopt a new 

airworthiness directive (AD) for the 

products listed above. This proposed 

AD results from mandatory continuing 

airworthiness information (MCAI) 

originated by an aviation authority of 

another country to identify and correct 

an unsafe condition on an aviation 

product. The MCAI describes the unsafe 

condition as: 

[T]here have been a number of occurrences 

with Messier-Dowty MLG [main landing 

gear] units where the main fitting failed, due 

to fatigue cracking in the area of the filler and 

bleeder holes, and occurrences where the 

sliding member failed, due to fatigue 

cracking at the area of chrome run-out/lower 

radius of the sliding tube portion of the 

sliding member. 

Investigation has revealed that the most 

probable cause of * * * cracks is high 

compressive stress during braking at higher 

deceleration levels outside the regular fatigue 

load spectrum. [T]he high compressive stress 

locally exceeds the elasticity limit of the 

material, leaving a residual tensile stress at 

release of the heavy braking load. 

Subsequently, this local residual tensile 

stress results in a negative effect on the 

fatigue life of the component. 

This condition, if not detected and 

corrected, could lead to failure of the MLG, 

possibly resulting in loss of control of the 

aeroplane during the landing rollout. * * * 

* * * * * 

The proposed AD would require actions 

that are intended to address the unsafe 

condition described in the MCAI. 

DATES: We must receive comments on 

this proposed AD by December 22, 

2011. 

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 W12–40, 1200 New Jersey 

Avenue SE., Washington, DC, between 9 

a.m. and 5 p.m., Monday through 

Friday, except Federal holidays. 

For Fokker service information 

identified in this proposed AD, contact 

Fokker Services B.V., Technical 

Services Dept., P.O. Box 231, 2150 AE 

Nieuw-Vennep, the Netherlands; 

telephone: +31 (0)252–627–350; fax: 

+31 (0)252–627–211; email: 

technicalservices.fokkerservices@stork.

com; Internet: http://www.

myfokkerfleet.com. 

For Messier-Dowty service 

information identified in this proposed 

AD, contact Messier Services Americas, 

Customer Support Center, 45360 Severn 

Way, Sterling, Virginia 20166–8910; 

telephone: (703) 450–8233; fax: (703) 

404–1621; Internet: https://techpubs.

services.messier-dowty.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 

Operations office between 9 a.m. and 

5 p.m., Monday through Friday, except 

Federal holidays. The AD docket 

contains this proposed AD, the 


srobinson on DSK4SPTVN1PROD with PROPOSALS