Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules 54749 

accordance with the procedures found in 14 

CFR 39.19. 

(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 appropriate principal inspector 

(PI) in the FAA Flight Standards District 

Office (FSDO), or lacking a PI, your local 

FSDO. 

Issued in Renton, Washington, on 

September 11, 2008. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E8–22220 Filed 9–22–08; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–1007; Directorate 

Identifier 2008–NM–135–AD] 

RIN 2120–AA64 

Airworthiness Directives; Bombardier 

Model CL–600–2C10 (Regional Jet 

Series 700, 701 & 702) Airplanes and 

Model CL–600–2D24 (Regional Jet 

Series 900) 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: Bombardier Aerospace has 

completed a system safety review of the 

CL–600–2C10/CL–600–2D24 aircraft 

fuel system against new fuel tank safety 

standards. The assessment showed that 

due to the close proximity of 

intrinsically safe fuel system wiring 

with other wiring, a single failure from 

wire chafing at various locations of the 

fuselage could result in an ignition 

source inside the fuel tank. In addition, 

chafing of the temperature sensor wiring 

against the high power wiring in the 

avionics compartment could lead to 

overheating of the temperature sensor 

and hot surface ignition. The presence 

of an ignition source inside the fuel tank 

could result in a fuel tank explosion. 

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 October 23, 2008. 

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. 

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 

regulatory evaluation, any comments 

received, and other information. The 

street address for the Docket Operations 

office (telephone (800) 647–5527) is in 

the ADDRESSES section. Comments will 

be available in the AD docket shortly 

after receipt. 

FOR FURTHER INFORMATION CONTACT: 

Rocco Viselli, Aerospace Engineer, 

Airframe and Propulsion Branch, ANE– 

171, FAA, New York Aircraft 

Certification Office, 1600 Stewart 

Avenue, Suite 410, Westbury, New York 

11590; telephone (516) 228–7331; fax 

(516) 794–5531. 

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–2008–1007; Directorate Identifier 

2008–NM–135–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 based on 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 

Transport Canada Civil Aviation 

(TCCA), which is the aviation authority 

for Canada, has issued Canadian 

Airworthiness Directive CF–2008–25, 

dated July 3, 2008 (referred to after this 

as ‘‘the MCAI’’), to correct an unsafe 

condition for the specified products. 

The MCAI states: 

Bombardier Aerospace has completed a 

system safety review of the CL–600–2C10/ 

CL–600–2D24 aircraft fuel system against 

new fuel tank safety standards, introduced in 

Chapter 525 of the Airworthiness Manual 

through Notice of Proposed Amendment 

(NPA) 2002–043. The identified noncompliances were assessed using Transport 

Canada Policy Letter No. 525–001 to 

determine if mandatory corrective action was 

required. 

The assessment showed that due to the 

close proximity of intrinsically safe fuel 

system wiring with other wiring, a single 

failure from wire chafing at various locations 

of the fuselage could result in an ignition 

source inside the fuel tank. In addition, 

chafing of the temperature sensor wiring 

against the high power wiring in the avionics 

compartment could lead to overheating of the 

temperature sensor and hot surface ignition. 

The presence of an ignition source inside the 

fuel tank could result in a fuel tank 

explosion. 

To correct the unsafe condition, this 

directive mandates the installation of conduit 

and the addition of spacers to protect fuel 

tank wiring. 

You may obtain further information by 

examining the MCAI in the AD docket. 

The FAA has examined the 

underlying safety issues involved in fuel 

tank explosions on several large 

transport airplanes, including the 

adequacy of existing regulations, the 

service history of airplanes subject to 

those regulations, and existing 

maintenance practices for fuel tank 

systems. As a result of those findings, 

we issued a regulation titled ‘‘Transport 

Airplane Fuel Tank System Design 

Review, Flammability Reduction and 

Maintenance and Inspection 

Requirements’’ (66 FR 23086, May 7, 

2001). In addition to new airworthiness 

standards for transport airplanes and 

new maintenance requirements, this 

rule included Special Federal Aviation 

Regulation No. 88 (‘‘SFAR 88,’’ 

Amendment 21–78, and subsequent 

Amendments 21–82 and 21–83). 

Among other actions, SFAR 88 

requires certain type design (i.e., type 

certificate (TC) and supplemental type 

certificate (STC)) holders to substantiate 

that their fuel tank systems can prevent 

ignition sources in the fuel tanks. This 

requirement applies to type design 

holders for large turbine-powered 

transport airplanes and for subsequent 

modifications to those airplanes. It 


jlentini on PROD1PC65 with PROPOSALS
54750 Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules 

requires them to perform design reviews 

and to develop design changes and 

maintenance procedures if their designs 

do not meet the new fuel tank safety 

standards. As explained in the preamble 

to the rule, we intended to adopt 

airworthiness directives to mandate any 

changes found necessary to address 

unsafe conditions identified as a result 

of these reviews. 

In evaluating these design reviews, we 

have established four criteria intended 

to define the unsafe conditions 

associated with fuel tank systems that 

require corrective actions. The 

percentage of operating time during 

which fuel tanks are exposed to 

flammable conditions is one of these 

criteria. The other three criteria address 

the failure types under evaluation: 

single failures, single failures in 

combination with a latent condition(s), 

and in-service failure experience. For all 

four criteria, the evaluations included 

consideration of previous actions taken 

that may mitigate the need for further 

action. 

We have determined that the actions 

identified in this AD are necessary to 

reduce the potential of ignition sources 

inside fuel tanks, which, in combination 

with flammable fuel vapors, could result 

in fuel tank explosions and consequent 

loss of the airplane. 

Relevant Service Information 

Bombardier has issued Service 

Bulletin 670BA–24–011, Revision C, 

dated November 28, 2005. The actions 

described in this service information are 

intended to correct the unsafe condition 

identified in the MCAI. 

FAA’s Determination and Requirements 

of This Proposed AD 

This product has been approved by 

the aviation authority of another 

country, and is approved for operation 

in the United States. Pursuant to our 

bilateral agreement with the State of 

Design Authority, we have been notified 

of the unsafe condition described in the 

MCAI and service information 

referenced above. We are proposing this 

AD because we evaluated all pertinent 

information and determined an unsafe 

condition exists and is likely to exist or 

develop on other products of the same 

type design. 

Differences Between This AD and the 

MCAI or Service Information 

We have reviewed the MCAI and 

related service information and, in 

general, agree with their substance. But 

we might have found it necessary to use 

different words from those in the MCAI 

to ensure the AD is clear for U.S. 

operators and is enforceable. In making 

these changes, we do not intend to differ 

substantively from the information 

provided in the MCAI and related 

service information. 

We might also have proposed 

different actions in this AD from those 

in the MCAI in order to follow FAA 

policies. Any such differences are 

highlighted in a NOTE within the 

proposed AD. 

Costs of Compliance 

Based on the service information, we 

estimate that this proposed AD would 

affect about 159 products of U.S. 

registry. We also estimate that it would 

take about 38 work-hours per product to 

comply with the basic requirements of 

this proposed AD. The average labor 

rate is $80 per work-hour. Required 

parts would cost about $2,914 per 

product. Where the service information 

lists required parts costs that are 

covered under warranty, we have 

assumed that there will be no charge for 

these costs. As we do not control 

warranty coverage for affected parties, 

some parties may incur costs higher 

than estimated here. Based on these 

figures, we estimate the cost of the 

proposed AD on U.S. operators to be 

$946,686, or $5,954 per product. 

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. 

We prepared a regulatory evaluation 

of the estimated costs to comply with 

this proposed AD and placed it in the 

AD docket. 

List of Subjects in 14 CFR Part 39 

Air transportation, Aircraft, Aviation 

safety, 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 AD: 

Bombardier, Inc. (Formerly Canadair): 

Docket No. FAA–2008–1007; Directorate 

Identifier 2008–NM–135–AD. 

Comments Due Date 

(a) We must receive comments by October 

23, 2008. 

Affected ADs 

(b) None. 

Applicability 

(c) This AD applies to the airplanes 

identified in paragraphs (c)(1) and (c)(2) of 

this AD, certificated in any category. 

(1) Bombardier Model CL–600–2C10 

(Regional Jet Series 700, 701, & 702) 

airplanes, serial numbers 10003 through 

10169 inclusive. 

(2) Bombardier Model CL–600–2D24 

(Regional Jet Series 900) airplanes, serial 

numbers 15001 through 15030 inclusive. 

Subject 

(d) Air Transport Association (ATA) of 

America Code 24: Electrical Power. 

Reason 

(e) The mandatory continuing 

airworthiness information (MCAI) states: 

Bombardier Aerospace has completed a 

system safety review of the CL–600–2C10/ 

CL–600–2D24 aircraft fuel system against 

new fuel tank safety standards, introduced in 

Chapter 525 of the Airworthiness Manual 

through Notice of Proposed Amendment 


jlentini on PROD1PC65 with PROPOSALS
Federal Register / Vol. 73, No. 185 / Tuesday, September 23, 2008 / Proposed Rules 54751 

(NPA) 2002–043. The identified noncompliances were assessed using Transport 

Canada Policy Letter No. 525–001 to 

determine if mandatory corrective action was 

required. 

The assessment showed that due to the 

close proximity of intrinsically safe fuel 

system wiring with other wiring, a single 

failure from wire chafing at various locations 

of the fuselage could result in an ignition 

source inside the fuel tank. In addition, 

chafing of the temperature sensor wiring 

against the high power wiring in the avionics 

compartment could lead to overheating of the 

temperature sensor and hot surface ignition. 

The presence of an ignition source inside the 

fuel tank could result in a fuel tank 

explosion. 

To correct the unsafe condition, this 

directive mandates the installation of conduit 

and the addition of spacers to protect fuel 

tank wiring. 

Actions and Compliance 

(f) Unless already done, do the following 

actions. 

(1) Within 4,500 flight hours after the 

effective date of this AD, modify the fuel 

system wiring along the fuselage and in the 

avionics compartment by installing 

protective conduit and spacers, in 

accordance with the Accomplishment 

Instructions of Bombardier Service Bulletin 

670BA–24–011, Revision C, dated November 

28, 2005. 

(2) Actions done before the effective date 

of this AD in accordance with Bombardier 

Service Bulletin 670BA–24–011, dated 

September 7, 2004; Revision A, dated 

December 14, 2004; or Revision B, dated 

February 28, 2005; are acceptable for 

compliance with the corresponding 

requirements of this AD. 

FAA AD Differences 

Note: This AD differs from the MCAI and/ 

or service information as follows: No 

differences. 

Other FAA AD Provisions 

(g) The following provisions also apply to 

this AD: 

(1) Alternative Methods of Compliance 

(AMOCs): The Manager, New York 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: Rocco 

Viselli, Aerospace Engineer, Airframe and 

Propulsion Branch, ANE–171, FAA, New 

York ACO, 1600 Stewart Avenue, Suite 410, 

Westbury, New York 11590; telephone (516) 

228–7331; fax (516) 794–5531. Before using 

any approved AMOC on any airplane to 

which the AMOC applies, notify your 

appropriate principal inspector (PI) in the 

FAA Flight Standards District Office (FSDO), 

or lacking a PI, your local FSDO. 

(2) Airworthy Product: For any 

requirement in this AD to obtain corrective 

actions from a manufacturer or other source, 

use these actions if they are FAA-approved. 

Corrective actions are considered FAAapproved if they are approved by the State 

of Design Authority (or their delegated 

agent). You are required to assure the product 

is airworthy before it is returned to service. 

(3) Reporting Requirements: For any 

reporting requirement in this AD, under the 

provisions of the Paperwork Reduction Act, 

the Office of Management and Budget (OMB) 

has approved the information collection 

requirements and has assigned OMB Control 

Number 2120–0056. 

Related Information 

(h) Refer to MCAI Canadian Airworthiness 

Directive CF–2008–25, dated July 3, 2008, 

and Bombardier Service Bulletin 670BA–24– 

011, Revision C, dated November 28, 2005, 

for related information. 

Issued in Renton, Washington, on 

September 12, 2008. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. E8–22218 Filed 9–22–08; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2008–0981; Directorate 

Identifier 2008–NM–073–AD] 

RIN 2120–AA64 

Airworthiness Directives; Boeing 

Model 747 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to 

supersede an existing airworthiness 

directive (AD) that applies to certain 

Boeing Model 747 airplanes. The 

existing AD currently requires repetitive 

inspections of the body station (BS) 

2598 bulkhead, and corrective actions if 

necessary. The existing AD also 

currently requires a terminating 

modification for the repetitive 

inspections and a post-modification 

inspection of the modified area. This 

proposed AD would continue requiring 

those actions with revised service 

information. For certain airplanes, this 

proposed AD would require new 

repetitive inspections, an interim 

modification, and post-interim 

modification inspections. For certain 

airplanes, this proposed AD also would 

require replacing any previously 

repaired aft inner chord and reinstalling 

the terminating modification. This 

proposed AD results from reports of 

cracked aft inner chords on airplanes 

after certain requirements of the existing 

AD were done. We are proposing this 

AD to prevent fatigue cracking of the BS 

2598 bulkhead structure, which could 

result in inability of the structure to 

carry horizontal stabilizer flight loads, 

and loss of controllability of the 

airplane. 

DATES: We must receive comments on 

this proposed AD by November 7, 2008. 

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 AD, contact Boeing Commercial 

Airplanes, P.O. Box 3707, Seattle, 

Washington 98124–2207. 

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. 

FOR FURTHER INFORMATION CONTACT: Ivan 

Li, Aerospace Engineer, Airframe 

Branch, ANM–120S, FAA, Seattle 

Aircraft Certification Office, 1601 Lind 

Avenue, SW., Renton, Washington 

98057–3356; telephone (425) 917–6437; 

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–2008–0981; Directorate Identifier 

2008–NM–073–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 


jlentini on PROD1PC65 with PROPOSALS