### 6581 Federal Register / Vol. 76, No. 25 / Monday, February 7, 2011 / Proposed Rules

(1) The associated interval for any new task is to be counted from April 9, 2007.

(2) The associated interval for any revised task is to be counted from the previous performance of the task.
New Requirements of This AD
Revise the Maintenance Program

(g) Unless already done, within 90 days of the effective date of this AD: Revise the maintenance program which ensures the continuing airworthiness of each operated airplane by incorporating Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010. At the times specified in the Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010, comply with all applicable maintenance requirements and associated airworthiness limitations included in Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010, except as provided by paragraphs (h) and (i) of this AD. Doing this revision terminates the requirements of paragraph (f) of this AD for that airplane only.
Exceptions to the CMR Tasks

(h) At the latest of the times specified in paragraph (h)(1), (h)(2), or (h)(3) of this AD: Do the first accomplishment of CMR Task 213100–00001–2–C of Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010.

(1) Before the accumulation of 48,000 total flight hours.

(2) Within 48,000 flight hours after the most recent accomplishment of Maintenance Review Board Report (MRBR) Task 21.31.00/

05.

(3) Within three months after the effective date of this AD.

(i) At the latest of the times specified in paragraph (i)(1), (i)(2), or (i)(3) of this AD: Do the first accomplishment of CMR Tasks 242000–00005–1–C, 243000–00001–1–C, and 243000–00002–1–C of Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010.

(1) Before the accumulation of 12,000 total flight hours.

(2) Within 12,000 flight hours after the most recent accomplishment of MRBR Task 24.20.00/17, 24.30.00/04, or 24.30.00/05 respectively.

(3) Within three months after the effective date of this AD.
No Alternative Inspections or Intervals

(j) After accomplishing the action required by paragraph (g) of this AD, no alternative inspections or inspection intervals may be used, unless the inspections or intervals are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (k)(1) of this AD.

FAA AD Differences

Note 2: This AD differs from the MCAI and/or service information as follows: No differences. Other FAA AD Provisions (k) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, ANM–116, International Branch, Transport Airplane Directorate, 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: Vladimir Ulyanov, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, Washington 98057–3356; telephone (425) 227–1138; fax (425) 227–1149. 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.

(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 FAA-approved 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.

Related Information

(l) Refer to EASA Airworthiness Directives 2006–0225, dated July 21, 2006, and 2010– 0264, dated December 20, 2010; Airbus A330 Certification Maintenance Requirements, Document 955.2074/93, Issue 19, dated March 22, 2006; and Airbus A330 ALS, Part 3—Certification Maintenance Requirements, Revision 03, dated July 29, 2010; for related information.

Issued in Renton, Washington, on January 28, 2011. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011–2611 Filed 2–4–11; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–0037; Directorate Identifier 2010–NM–273–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Airbus Model A300 B4–600, B4–600R, and F4–600R**  **Series Airplanes, and Model C4–605R Variant F Airplanes (Collectively Called**  **A300–600 Series 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]he FAA has published SFAR 88 (Special Federal Aviation Regulation 88).

In their letters referenced 04/00/02/07/01– L296, dated March 4th, 2002, and 04/00/02/ 07/03–L024, dated February 3rd, 2003, the JAA [Joint Aviation Authorities] recommended the application of a similar regulation to the National Aviation Authorities (NAA).

Under this regulation, all holders of type certificates for passenger transport aircraft * * * are required to conduct a design review against explosion risks.

During improvement of the protection of fuel pump wiring against short-circuit by accomplishment of Airbus Service Bulletin (SB) A300–24–6094, a study led by the manufacturer concluded that the harness, installed through the wing panel needed to be protected to prevent possible damage in case of chafing which could potentially lead to short-circuit [and intermittent function or loss of the inner tank fuel pump. Loss of both inner tank fuel pumps could result in inability to use the remaining fuel supply in the inner tank. A short-circuit could also result in an ignition source in a flammable leakage zone].
* * * * *

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 March 24, 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 service information identified in this proposed AD, contact Airbus SAS— EAW (Airworthiness Office), 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France; telephone +33 5 61 93 36 96; fax +33 5 61 93 44 51; e-mail: account.airworth-eas@airbus.com; Internet http://www.airbus.com. You


### 6582 Federal Register / Vol. 76, No. 25 / Monday, February 7, 2011 / Proposed Rules

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 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 :**  Dan Rodina, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, Washington 98057–3356; telephone (425) 227–2125; fax (425) 227–1149.

**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–2011–0037; Directorate Identifier 2010–NM–273–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

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued EASA Airworthiness Directive 2010–0225, dated November 5, 2010 (referred to after this as ‘‘the MCAI’’ ), to correct an unsafe condition for the specified products. The MCAI states:

[T]he FAA has published SFAR 88 (Special Federal Aviation Regulation 88).

In their letters referenced 04/00/02/07/01– L296, dated March 4th, 2002, and 04/00/02/ 07/03–L024, dated February 3rd, 2003, the JAA [Joint Aviation Authorities] recommended the application of a similar regulation to the National Aviation Authorities (NAA).

Under this regulation, all holders of type certificates for passenger transport aircraft with either a passenger capacity of 30 or more, or a payload capacity of 3,402 kg (7,500 lb) or more, which have received their certification since January 1st, 1958, are required to conduct a design review against explosion risks.

During improvement of the protection of fuel pump wiring against short-circuit by accomplishment of Airbus Service Bulletin (SB) A300–24–6094, a study led by the manufacturer concluded that the harness, installed through the wing panel needed to be protected to prevent possible damage in case of chafing which could potentially lead to short-circuit [and intermittent function or loss of the inner tank fuel pump. Loss of both inner tank fuel pumps could result in inability to use the remaining fuel supply in the inner tank. A short-circuit could also result in an ignition source in a flammable leakage zone].

For the reasons stated above, this [EASA] AD requires the replacement of bushes in the hydraulic reservoir panel.

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 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.

The Joint Aviation Authorities (JAA) has issued a regulation that is similar to SFAR 88. (The JAA is an associated body of the European Civil Aviation Conference (ECAC) representing the civil aviation regulatory authorities of a number of European States who have agreed to co-operate in developing and implementing common safety regulatory standards and procedures.) Under this regulation, the JAA stated that all members of the ECAC that hold type certificates for transport category airplanes are required to conduct a design review against explosion risks.

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

Airbus has issued Mandatory Service Bulletin A300–24–6102, Revision 01, dated September 24, 2010. 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.


### 6583 Federal Register / Vol. 76, No. 25 / Monday, February 7, 2011 / Proposed Rules

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 120 products of U.S. registry. We also estimate that it would take about 13 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $85 per work-hour. Required parts would cost about $266 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 $164,520, or $1,371 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, 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 AD:

Airbus: Docket No. FAA–2011–0037; Directorate Identifier 2010–NM–273–AD.

Comments Due Date

(a) We must receive comments by March 24, 2011.

Affected ADs

(b) None.
Applicability

(c) This AD applies to all Airbus Model A300 B4–601, B4–603, B4–620, B4–622, B4– 605R, B4–622R, F4–605R, F4–622R, and C4– 605R Variant F airplanes, certificated in any category, all certified models, all serial numbers, except airplanes on which Airbus Service Bulletin A300–24–6102 (Airbus Modification 13381) has been embodied.
Subject

(d) Air Transport Association (ATA) of America Code 24: Electrical Power. Reason (e) The mandatory continuing airworthiness information (MCAI) states:

[T]he FAA has published SFAR 88 (Special Federal Aviation Regulation 88).

In their letters referenced 04/00/02/07/01– L296, dated March 4th, 2002, and 04/00/02/ 07/03–L024, dated February 3rd, 2003, the JAA [Joint Aviation Authorities] recommended the application of a similar regulation to the National Aviation Authorities (NAA).

Under this regulation, all holders of type certificates for passenger transport aircraft * * * are required to conduct a design review against explosion risks.

During improvement of the protection of fuel pump wiring against short-circuit by accomplishment of Airbus Service Bulletin (SB) A300–24–6094, a study led by the manufacturer concluded that the harness, installed through the wing panel needed to be protected to prevent possible damage in case of chafing which could potentially lead to short-circuit [and intermittent function or loss of the inner tank fuel pump. Loss of both inner tank fuel pumps could result in inability to use the remaining fuel supply in the inner tank. A short-circuit could also result in an ignition source in a flammable leakage zone].
* * * * *
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.

Actions

(g) Within 30 months after the effective date of this AD, install Teflon bushes in thehydraulic reservoir panel at the lower lefthand side in accordance with the Accomplishment Instructions of Airbus Mandatory Service Bulletin A300–24–6102, Revision 01, dated September 24, 2010.
Credit for Actions Accomplished in Accordance With Previous Service Information

(h) Actions done before the effective date of this AD in accordance with Airbus Mandatory Service Bulletin A300–24–6102, dated August 13, 2009, are acceptable for compliance with the corresponding requirements of this AD.

FAA AD Differences

Note 1: This AD differs from the MCAI and/or service information as follows: No differences.

Other FAA AD Provisions

(i) The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM–116, Transport Airplane Directorate, 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: Dan Rodina, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton,


### 6584 Federal Register / Vol. 76, No. 25 / Monday, February 7, 2011 / Proposed Rules

Washington 98057–3356; telephone (425) 227–2125; fax (425) 227–1149. Information may be e-mailed to: 9-ANM-116-AMOCREQUESTS@faa.gov. 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. The AMOC approval letter must specifically reference this AD.

(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 FAA-approved 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.

Related Information

(j) Refer to MCAI European Aviation Safety Agency Airworthiness Directive 2010–0225, dated November 5, 2010; and Airbus Mandatory Service Bulletin A300–24–6102, Revision 01, dated September 24, 2010; for related information.

Issued in Renton, Washington, on January 31, 2011. Ali Bahrami, Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2011–2612 Filed 2–4–11; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–0036; Directorate Identifier 2010–NM–230–AD]** 

**RIN 2120–AA64**

**Airworthiness Directives; Bombardier, Inc. Model DHC–8–400 Series**  **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 aeroplanes fuel system against fuel tank safety standards introduced in Chapter 525 of the Airworthiness Manual through Notice of Proposed Amendment (NPA) 2002–043 [which corresponds with the FAA’s Special Federal Aviation Regulation (SFAR) 88]. The identified non-compliances were then assessed using Transport Canada Policy Letter No. 525–001, to determine if mandatory corrective action is required.

The assessment showed that a number of modifications to the fuel system are required to mitigate unsafe conditions that could result in potential ignition source within the fuel system.

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 March 24, 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 service information identified in this proposed AD, contact Bombardier, Inc., Q–Series Technical Help Desk, 123 Garratt Boulevard, Toronto, Ontario M3K 1Y5, Canada; telephone 416–375– 4000; fax 416–375–4539; e-mail thd.qseries@aero.bombardier.com; Internet http://www.bombardier.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 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 :**  James Delisio, Aerospace Engineer, Propulsion and Services Branch, ANE– 173, FAA, New York Aircraft Certification Office, 1600 Stewart Avenue, Suite 410, Westbury, New York 11590; telephone (516) 228–7321; 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–2011–0036; Directorate Identifier 2010–NM–230–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–2010–31, dated September 3, 2010 (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 aeroplanes fuel system against fuel tank safety standards introduced in Chapter 525 of the Airworthiness Manual through Notice of Proposed Amendment (NPA) 2002–043 [which corresponds with the FAA’s Special Federal Aviation Regulation (SFAR) 88]. The identified non-compliances were then assessed using Transport Canada Policy Letter No. 525–001, to determine if mandatory corrective action is required.

The assessment showed that a number of modifications to the fuel system are required to mitigate unsafe conditions that could result in potential ignition source within the fuel system.

The Bombardier modifications include:

• Modsum 4–126330, ‘‘Fuel Tank System Design Left and Right Side (SFAR 88) Retrofit. ’’ The retrofit includes replacing certain fittings, couplings, o-rings, gaskets, fuel adapter, and other related components with new, improved parts; applying alodine 1132 to certain areas of a wing rib and a wing spar; and replacing a certain doubler on the front wing spar with a new, improved doubler.

• Modsum 4–126366, ‘‘Fuel Tank System and Fuel Indication—Wiring Identification, Segregation and