54576 Federal Register / Vol. 79, No. 177 / Friday, September 12, 2014 / Rules and Regulations 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2014–0329; Special 

Conditions No. 25–560–SC] 

Special Conditions: Bombardier 

Aerospace, Models BD–500–1A10 and 

BD–500–1A11 Series Airplanes; Tire 

Debris Impacts to Fuel Tanks 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for the Bombardier Aerospace, 

Models BD–500–1A10 and BD–500– 

1A11 series airplanes. These airplanes 

will have a novel or unusual design 

feature associated with the use of carbon 

fiber reinforced plastic (CFRP) for most 

of the wing fuel tank structure, which, 

when impacted by tire debris, may resist 

penetration or rupture differently from 

aluminum wing skins. The applicable 

airworthiness regulations do not contain 

adequate or appropriate safety standards 

for this design feature. These special 

conditions contain the additional safety 

standards that the Administrator 

considers necessary to establish a level 

of safety equivalent to that established 

by the existing airworthiness standards. 

DATES: Effective Date: October 14, 2014. 

FOR FURTHER INFORMATION CONTACT: 

Margaret Langsted, FAA, Propulsion 

and Mechanical Systems Branch, ANM– 

112, Transport Airplane Directorate, 

Aircraft Certification Service, 1601 Lind 

Avenue SW., Renton, Washington, 

98057–3356; telephone 425–227–2677; 

facsimile 425–227–1149. 

SUPPLEMENTARY INFORMATION: 

Background 

On December 10, 2009, Bombardier 

Aerospace applied for a type certificate 

for their new Models BD–500–1A10 and 

BD–500–1A11 series airplanes (hereafter 

collectively referred to as ‘‘CSeries’’). 

The CSeries airplanes are swept-wing 

monoplanes with an aluminum alloy 

fuselage sized for 5-abreast seating. 

Passenger capacity is designated as 110 

for the Model BD–500–1A10 and 125 for 

the Model BD–500–1A11. Maximum 

takeoff weight is 131,000 pounds for the 

Model BD–500–1A10 and 144,000 

pounds for the Model BD–500–1A11. 

Type Certification Basis 

Under the provisions of Title 14, Code 

of Federal Regulations (14 CFR) 21.17, 

Bombardier Aerospace must show that 

the CSeries airplanes meet the 

applicable provisions of part 25, as 

amended by Amendments 25–1 through 

25–129 thereto. 

If the Administrator finds that the 

applicable airworthiness regulations 

(i.e., 14 CFR part 25) do not contain 

adequate or appropriate safety standards 

for the CSeries airplanes because of a 

novel or unusual design feature, special 

conditions are prescribed under the 

provisions of § 21.16. 

Special conditions are initially 

applicable to the model for which they 

are issued. Should the type certificate 

for that model be amended later to 

include any other model that 

incorporates the same or similar novel 

or unusual design feature, the special 

conditions would also apply to the other 

model under § 21.101. 

In addition to the applicable 

airworthiness regulations and special 

conditions, the CSeries airplanes must 

comply with the fuel vent and exhaust 

emission requirements of 14 CFR part 

34 and the noise certification 

requirements of 14 CFR part 36, and the 

FAA must issue a finding of regulatory 

adequacy under section 611 of Public 

Law 92–574, the ‘‘Noise Control Act of 

1972.’’ 

The FAA issues special conditions, as 

defined in 14 CFR 11.19, in accordance 

with § 11.38, and they become part of 

the type-certification basis under 

§ 21.17(a)(2). 

Novel or Unusual Design Features 

The CSeries airplanes will incorporate 

the following novel or unusual design 

features: The use of carbon fiber 

reinforced plastic (CFRP) for most of the 

wing fuel tank structure. The ability of 

aluminum wing skins to resist 

penetration or rupture when impacted 

by tire debris is understood from 

extensive experience, but the ability of 

CFRP construction to resist these 

hazards has not been established. There 

are no existing regulations that 

adequately establish a level of safety 

with respect to the performance of the 

composite materials used in the 

construction of wing fuel tanks. It 

requires the consideration of fuel tank 

penetration, fuel leaks, discrete source 

damage tolerance, and the effects of 

shock waves generated by tire debris 

impact. 

Discussion 

Accidents have resulted from 

uncontrolled fires caused by fuel leaks 

following penetration or rupture of the 

lower wing by fragments of tires or from 

uncontained engine failure. The 

Concorde accident in 2000 is the most 

notable example. That accident 

demonstrated an unanticipated failure 

mode in an airplane with an unusual 

transport airplane configuration. Impact 

to the lower wing surface by tire debris 

induced pressure waves within the fuel 

tank that resulted in fuel leakage and 

fire. Regulatory authorities subsequently 

required modifications to the Concorde 

to improve impact resistance of the 

lower wing or means to retain fuel if the 

primary fuel retention means is 

damaged. 

In another incident, a Boeing Model 

747 tire burst during an aborted takeoff 

from Honolulu, Hawaii. That tire debris 

penetrated a fuel tank access cover, 

causing substantial fuel leakage. 

Passengers were evacuated down the 

emergency chutes into pools of fuel that 

fortunately had not ignited. 

These accidents highlight deficiencies 

in the existing regulations pertaining to 

fuel retention following impact of the 

fuel tanks by tire fragments. Following 

a 1985 Boeing Model 737 accident in 

Manchester, England, in which a fuel 

tank access panel was penetrated by 

engine debris, the FAA amended 14 

CFR 25.963 to require fuel tank access 

panels that are resistant to both tire and 

engine debris (engine debris is 

addressed elsewhere). This regulation, 

§ 25.963(e), only addressed the fuel tank 

access covers since service experience at 

the time showed that the lower wing 

skin of a conventional, subsonic 

airplane provided adequate inherent 

capability to resist tire and engine 

debris threats. More specifically, that 

regulation requires showing by analysis 

or tests that the access covers ‘‘. . . 

minimize penetration and deformation 

by tire fragments, low energy engine 

debris, or other likely debris.’’ Advisory 

Circular (AC) 25.963–1, Fuel Tank 

Access Covers, describes the region of 

the wing that is vulnerable to impact 

damage from these sources and provides 

a method to substantiate that the rule 

has been met for tire fragments. No 

specific requirements were established 

for the contiguous wing areas into 

which the access covers are installed, 

because of the inherent ability of 

conventional aluminum wing skins to 

resist penetration by tire debris. AC 

25.963–1 specifically notes, ‘‘The access 

covers, however, need not be more 

impact resistant than the contiguous 

tank structure,’’ highlighting the 

assumption that the wing structure is 

more capable of resisting tire impact 

debris than fuel tank access covers. 

These special conditions contain the 

additional safety standards that the 

Administrator considers necessary to 

establish a level of safety equivalent to 

that established by the existing 

airworthiness standards. To maintain 

the level of safety envisioned by 14 CFR 

25.963(e), these special conditions 

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Federal Register / Vol. 79, No. 177 / Friday, September 12, 2014 / Rules and Regulations 54577 

establish a standard for resistance to 

potential tire debris impacts to the 

contiguous wing surfaces and require 

consideration of possible secondary 

effects of a tire impact, such as the 

induced pressure wave that was a factor 

in the Concorde accident. It takes into 

account that new construction methods 

and materials will not necessarily yield 

debris resistance that has historically 

been shown as adequate. The standard 

in these special conditions is based on 

the defined tire impact areas and tire 

fragment characteristics. 

In addition, despite practical design 

considerations, some uncommon debris 

larger than that defined in paragraph 2 

may cause a fuel leak within the defined 

area, so paragraph 3 of these special 

conditions also takes into consideration 

possible leakage paths. Fuel tank 

surfaces of typical transport airplanes 

have thick aluminum construction in 

the tire debris impact areas that is 

tolerant to tire debris larger than that 

defined in paragraph 2 of these special 

conditions. Consideration of leaks 

caused by larger tire fragments is 

needed to ensure that an adequate level 

of safety is provided. 

Discussion of Comments 

Notice of proposed special conditions 

No. 25–14–03–SC for the Bombardier 

Aerospace CSeries airplanes was 

published in the Federal Register on 

June 3, 2014, (79 FR 31886). No 

comments were received, and the 

special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to the BD– 

500–1A10 and BD–500–1A11 series 

airplanes. Should Bombardier 

Aerospace apply at a later date for a 

change to the type certificate to include 

another model on the same type 

certificate incorporating the same novel 

or unusual design feature, these special 

conditions would apply to that model as 

well. 

Conclusion 

This action affects only certain novel 

or unusual design features on one model 

series of airplanes. It is not a rule of 

general applicability. 

List of Subjects in 14 CFR Part 25 

Aircraft, Aviation safety, Reporting 

and recordkeeping requirements. 

The authority citation for these 

special conditions is as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701, 

44702, 44704. 

The Special Conditions 

■ Accordingly, pursuant to the authority 

delegated to me by the Administrator, 

the following special conditions are 

issued as part of the type certification 

basis for Bombardier Aerospace Models 

BD–500–1A10 and BD–500–1A11 series 

airplanes. 

Tire Debris Impacts to Fuel Tanks 

1. Impacts by tire debris to any fuel 

tank or fuel system component located 

within 30 degrees to either side of wheel 

rotational planes may not result in 

penetration or otherwise induce fuel 

tank deformation, rupture (for example, 

through propagation of pressure waves), 

or cracking sufficient to allow a 

hazardous fuel leak. A hazardous fuel 

leak results if debris impact to a fuel 

tank surface causes a— 

a. Running leak, 

b. Dripping leak, or 

c. Leak that, 15 minutes after wiping 

dry, results in a wetted airplane surface 

exceeding 6 inches in length or 

diameter. 

The leak must be evaluated under 

maximum fuel head pressure. 

2. Compliance with paragraph 1 must 

be shown by analysis or tests assuming 

all of the following: 

a. The tire debris fragment size is 1 

percent of the tire mass. 

b. The tire debris fragment is 

propelled at a tangential speed that 

could be attained by a tire tread at the 

airplane flight manual airplane 

rotational speed (VR at maximum gross 

weight). 

c. The tire debris fragment load is 

distributed over an area on the fuel tank 

surface equal to 11⁄2 percent of the total 

tire tread area. 

3. Fuel leaks caused by impact from 

tire debris larger than that specified in 

paragraph 2, from any portion of a fuel 

tank or fuel system component located 

within the tire debris impact area 

defined in paragraph 1, may not result 

in hazardous quantities of fuel entering 

any of the following areas of the 

airplane: 

a. Engine inlet, 

b. Auxiliary power unit inlet, or 

c. Cabin air inlet. 

This must be shown by test or 

analysis, or a combination of both, for 

each approved engine forward thrust 

condition and each approved reverse 

thrust condition. 

Issued in Renton, Washington, on 

September 3, 2014. 

Michael Kaszycki, 

Acting Manager, Transport Airplane 

Directorate, Aircraft Certification Service. 

[FR Doc. 2014–21786 Filed 9–11–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2014–0647; Directorate 

Identifier 2014–CE–027–AD; Amendment 

39–17967; AD 2014–18–03] 

RIN 2120–AA64 

Airworthiness Directives; APEX 

Aircraft Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final rule; request for 

comments. 

SUMMARY: We are adopting a new 

airworthiness directive (AD) for APEX 

Aircraft Model R 3000/160 airplanes. 

This AD results from mandatory 

continuing airworthiness information 

(MCAI) issued by the aviation authority 

of another country to identify and 

correct an unsafe condition on an 

aviation product. The MCAI describes 

the unsafe condition as small pieces of 

paint from the engine air intake box 

blocking the engine carburetor. We are 

issuing this AD to require actions to 

address the unsafe condition on these 

products. 

DATES: This AD is effective October 17, 

2014. 

The Director of the Federal Register 

approved the incorporation by reference 

of a certain publication listed in the AD 

as of October 17, 2014. 

We must receive comments on this 

AD by October 27, 2014. 

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 CEAPR, Bureau de 

Navigabilite ́, 1 route de Troyes, 21121 

DAROIS—France, telephone: (33) 380 

35 25 22; fax: (33) 380 35 25 25; email: 

www.info@ceapr.com; internet: http://

ceapr.com/. You may review copies of 

the referenced service information at the 

FAA, Small Airplane Directorate, 901 

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