U.S. Department 

of Transportation 

Federal Aviation 

Administration 

JUN 1 7 2015 

Mr. John Kotnjek 

Airworthiness Manager 

Bombardier Commercial Aircraft 

13100 Henri-Fabre Blvd. 

Mirabel, Quebec Canada J7N 3C6 

Dear Mr. Kotnjek: 

Transport Airplane Directorate 

1601 Lind Ave, SW. 

Renton, Washington 98057-3356 

Exemption No. 10 175A 

Regulatory Docket No. F AA-20 10-0287 

This letter is to inform you that we have denied your request for an extension to 

exemption no. 10175. It transmits our decision and explains its basis. 

By letter no. AW-CRJ/12/746 dated November 19, 2012, and letter no. A W-CRJ/14/752 

dated November 10, 2014, Mr. John Kotnjek, on behalf of Bombardier Inc. , petitioned 

the Federal Aviation Administration (FAA) for an extension to time-limited exemption 

no. 10175, to December 17,2015. That exemption, which expired December 17, 2012, 

allowed Bombardier Model CL-600-2E25 airplanes to receive FAA airworthiness 

certificates for a limited time. during which Bombardier was not required to show the 

airplanes to be in compliance with certain fuel-tank ignition-prevention standards of Title 

14, Code ofFederal Regulations (14 CFR) 25.981(a)(3), as discussed in FAA Policy 

Memorandum ANM-112-08-002. Exemption no. 10175 required Bombardier to complete 

the following activity by December 17, 2012: 

1. Instead of compliance with the requirements of§ 25.981(a)(3), Bombardier must 

show that the design includes at least two independent, effective, and reliable 

I ightning protection features (or sets of features) such that fault tolerance to 

prevent lightning-related ignition sources is provided for each area of the 

structural design that they have shown and the FAA has determined to be 

impractical for full compliance. 
a. Bombardier must identify all features that meet this two-layer protection 

provision and all features that do not include two layers. 

b. If there are features that do not meet this two-layer protection provision, 

Bombardier must petition to expand this exemption to include the nonfault-tolerant provision described in FAA Policy Memorandum ANM112-08-002, "Policy on Issuance of Special Conditions and Exemptions 

Related to Lightning Protection of Fuel Tank Structure," dated May 26, 

2009. 

2. Bombardier must perform an analysis to show that the design, manufacturing 

processes, and airworthiness limitations section of the instructions for continued 

airworthiness include all practical measures to prevent, and detect and correct, 

failures of structural lightning protection features because of manufacturing 

variability, aging, wear, corrosion, and likely damage. 

The Basis for Our Decision 

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Your petition requesting an extension of the time-limited exemption states, in pertinent 

part, that Bombardier had completed all testing that had been agreed as part of 

electromagnetic compatibility (EMC) test plan TDS-698-28-BA-2028 revision A. The 

results of these tests were originally intended to provide the substantiation needed to 

demonstrate compliance for a fault tolerant design. Note that, for areas that were found to 

not be fault tolerant, compliance would be shown through a safety assessment where fuelvapor ignition would be shown to be extremely improbable. 

EMC testing through the above noted document, TDS-698-28-BA-2028 revision A, 

yielded some unforeseen results. This means that Bombardier will need to complete 

additional testing and analysis, which has led to Bombardier requiring more time to 

complete its compliance demonstration beyond the December 17, 2012, date. 

Supporting the Bombardier compliance plan are the following documents: 

• EMC memo CRJ900-01-66-2012-33 , dated October 12, 2012, outlines the 

structural-aspects compliance plan for this requirement, based on the additional 

testing and analysis required. 

• Fuel-systems memo CRJ 1000/28/201 0/001 /EH, dated March 29, 2010, outlines 

the systems-related compliance plan for this requirement (no change from the 

original Bombardier petition). 

• A Reliability, Maintainability, and Safety memo, dated March 29, 2010, outlining 

the safety-assessment-procedures plan for the structural aspects of this 

requirement (no change from original Bombardier petition). 
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The FAA granted the original exemption for the Model CL-600-2E25 in 20 I 0. providing 

Bombardier a reasonable amount of extra time, after the FAA granted the type certificate, 

to complete unexpected compliance activity. That exemption permitted Bombardier time 

to demonstrate that the structural design provides two independent, effective, and reliable 

means of lightning-strike protection, in lieu of demonstrating full compliance with 14 

CFR 25.981(a)(3), for the structural aspects of the fuel-tank design where Bombardier 

showed that full compliance was not practical. We expected that Bombardier would 

complete the activity shortly thereafter and established the 2012 deadline accordingly. 

Since the time Bombardier petitioned for an extension to the existing exemption, the 

FAA has requested updated schedules from Bombardier indicating when they would 

complete their redesign, testing, and analysis as required by provisions I and 2 of the 

original exemption. Bombardier has not submitted a tirm schedule, which is required for 

FAA determination and evaluation of the extension request. Additionally, Bombardier 

has not identified sufficient public interest in the U.S. that would support the FAA 

granting an extension to the exemption. Granting or denying an extension to the 

exemption has no effect on Bombardier's ability to schedule and complete the testing and 

analysis required by the original exemption. After Bombardier has completed this 

activity, Bombardier should have the technical data and rationale that better supports 

public interest for an amended exemption. 

After Bombardier successfully completes the testing and analysis, they can re-petition for 

an amendment to exemption no. I 0175 seeking relief in the specific areas of the structural 

design for which they show, and the FAA finds, full compliance is not practical. After 

Bombardier completes this activity, and petitions for and receives an amended exemption, 

Bombardier may be eligible to receive FAA airworthiness certificates for Model CL-600-

2E25 airplanes. 

In summary, the original exemption expired on December 17, 2012. Bombardier has not 

provided to the FAA sufficient supporting data to justify an extension to the original 

exemption's time limit. 

Having reviewed your reasons for requesting an amended exemption, I find that granting 

an extension to the time limit of exemption no. 10175 would not be in the public interest. 

Federal Register publication 

The FAA published a summary ofthe petition in the Federal Register for public 

comment on January 7, 2013 (78 FR 978). No comments were received. 
Our decision 

Under the authority contained in 49 U.S.C. 40113 and 44701 , which the FAA Administrator 

has delegated to me, I hereby deny your petition for an extension to exemption no. 10175. 

This letter must be attached to, and is a part of, exemption no. 1017 5. 

Sincerely, 

£.0-_. 

Jeffrey E. Duven 

Manager, Transport Airplane Directorate 

Aircraft Certification Service 

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