This section of the FEDERAL REGISTER

contains notices to the public of the proposed

issuance of rules and regulations. The

purpose of these notices is to give interested

persons an opportunity to participate in the

rule making prior to the adoption of the final

rules.

Proposed Rules Federal Register

20774 

Vol. 72, No. 80 

Thursday April 26, 2007 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. NM373 Special Conditions No. 

25–07–09–SC] 

Special Conditions: Boeing Model 787– 

8 Airplane; Composite Fuselage InFlight Fire/Flammability Resistance 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Notice of proposed special 

conditions. 

SUMMARY: This notice proposes special 

conditions for the Boeing Model 787–8 

airplane. This airplane will have novel 

or unusual design features when 

compared to the state of technology 

envisioned in the airworthiness 

standards for transport category 

airplanes. The fuselage of the Boeing 

Model 787–8 series airplane will be 

made of composite materials rather than 

conventional aluminum. While the 

regulations include flame propagation 

standards for some materials commonly 

found in inaccessible areas of the 

airplane, they do not yet incorporate 

standards for materials used to construct 

the fuselage. Therefore, special 

conditions are needed to address this 

design feature. These proposed 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. 

Additional special conditions will be 

issued for other novel or unusual design 

features of the Boeing Model 787–8 

airplanes. 

DATES: Comments must be received on 

or before June 11, 2007. 

ADDRESSES: Comments on this proposal 

may be mailed in duplicate to: Federal 

Aviation Administration, Transport 

Airplane Directorate, Attention: Rules 

Docket (ANM–113), Docket No. NM373, 

1601 Lind Avenue SW., Renton, 

Washington 98057–3356; or delivered in 

duplicate to the Transport Airplane 

Directorate at the above address. All 

comments must be marked Docket No. 

NM373. Comments may be inspected in 

the Rules Docket weekdays, except 

Federal holidays, between 7:30 a.m. and 

4 p.m. 

FOR FURTHER INFORMATION CONTACT: Jeff 

Gardlin, FAA, Airframe/Cabin Safety, 

ANM–115, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Avenue SW., 

Renton, Washington 98057–3356; 

telephone (425) 227–2136; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

The FAA invites interested persons to 

participate in this rulemaking by 

submitting written comments, data, or 

views. The most helpful comments 

reference a specific portion of the 

special conditions, explain the reason 

for any recommended change, and 

include supporting data. We ask that 

you send us two copies of written 

comments. 

We will file in the docket all 

comments we receive as well as a report 

summarizing each substantive public 

contact with FAA personnel concerning 

these proposed special conditions. The 

docket is available for public inspection 

before and after the comment closing 

date. If you wish to review the docket 

in person, go to the address in the 

ADDRESSES section of this notice 

between 7:30 a.m. and 4 p.m., Monday 

through Friday, except Federal holidays. 

We will consider all comments we 

receive on or before the closing date for 

comments. We will consider comments 

filed late if it is possible to do so 

without incurring expense or delay. We 

may change the proposed special 

conditions based on comments we 

receive. 

If you want the FAA to acknowledge 

receipt of your comments on this 

proposal, include with your comments 

a pre-addressed, stamped postcard on 

which the docket number appears. We 

will stamp the date on the postcard and 

mail it back to you. 

Background 

On March 28, 2003, Boeing applied 

for an FAA type certificate for its new 

Boeing Model 787–8 passenger airplane. 

The Boeing Model 787–8 airplane will 

be an all-new, two-engine jet transport 

airplane with a two-aisle cabin. The 

maximum takeoff weight will be 

476,000 pounds, with a maximum 

passenger count of 381 passengers. 

Type Certification Basis 

Under provisions of 14 CFR 21.17, 

Boeing must show that Boeing Model 

787–8 airplanes (hereafter referred to as 

‘‘the 787’’) meet the applicable 

provisions of 14 CFR part 25, as 

amended by Amendments 25–1 through 

25–117, except §§ 25.809(a) and 25.812, 

which will remain at Amendment 25– 

115. If the Administrator finds that the 

applicable airworthiness regulations do 

not contain adequate or appropriate 

safety standards for the 787 because of 

a novel or unusual design feature, 

special conditions are prescribed under 

provisions of 14 CFR 21.16. 

In addition to the applicable 

airworthiness regulations and special 

conditions, the 787 must comply with 

the fuel vent and exhaust emission 

requirements of 14 CFR part 34 and the 

noise certification requirements of part 

36. In addition, the FAA must issue a 

finding of regulatory adequacy pursuant 

to section 611 of Public Law 92–574, the 

‘‘Noise Control Act of 1972.’’ 

Special conditions, as defined in 

§ 11.19, are issued in accordance with 

§ 11.38 and become part of the type 

certification basis in accordance with 

§ 21.17(a)(2). 

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 provisions of § 21.101. 

Novel or Unusual Design Features 

In-flight fires have originated in 

inaccessible areas of aircraft where 

thermal/acoustic insulation located 

adjacent to the aluminum aircraft skin 

has been the path for flame propagation 

and fire growth. Although these 

insulation materials were required to 

comply with the basic ‘‘Bunsen burner’’ 

requirement of title 14 Code of Federal 

Regulations (CFR) sections 25.853(a) 

and 25.855(d), these incidents revealed 

unexpected flame spread along the 

insulation film covering material of the 

thermal/acoustic insulation. In all cases, 

the ignition source was relatively 

modest and, in most cases, was 


jlentini on PROD1PC65 with PROPOSALS
Federal Register / Vol. 72, No. 80 / Thursday April 26, 2007 / Proposed Rules 20775 

electrical in origin (for example an 

electrical short circuit, arcing caused by 

chafed wiring, or a ruptured ballast 

case). 

In September 2003, in an effort to 

limit use of materials that sustain or 

propagate a fire in inaccessible areas, 

the FAA promulgated 14 CFR 25.856(a), 

which requires that thermal/acoustic 

insulation material installed in the 

fuselage meet newly developed flame 

propagation test requirements. That rule 

was Amendment 25–111. These 

requirements were developed to address 

a realistic fire threat. We consider that 

threat generally applicable to the 787. 

Conventional aluminum fuselage 

material does not contribute to in-flight 

fire propagation. As a result, there are 

no standards that address in-flight fire 

safety of the fuselage structure itself. 

The 787 will make extensive use of 

composite materials in the fabrication of 

the majority of the 

• Wing, 

• Fuselage skin, 

• Stringers, 

• Spars, and 

• Most other structural elements of all 

major sub-assemblies of the airplane. 

As a result of this extensive use of a new 

construction material, the fuselage 

cannot be assumed to have the fire 

resistance previously afforded by 

aluminum during the in-flight fire 

scenario mentioned above. These 

proposed special conditions would 

require that the 787 provide the same 

level of in-flight survivability as a 

conventional aluminum fuselage 

airplane. This includes its thermal/ 

acoustic insulation meeting 

requirements of § 25.856(a). Resistance 

to flame propagation must be shown, 

and all products of combustion that may 

result must be evaluated for toxicity and 

found acceptable. 

Applicability 

As discussed above, these proposed 

special conditions are applicable to the 

787. Should Boeing apply at a later date 

for a change to the type certificate to 

include another model incorporating the 

same novel or unusual design features, 

these proposed special conditions 

would apply to that model as well 

under the provisions of § 21.101. 

Conclusion 

This action affects only certain novel 

or unusual design features of the 787. It 

is not a rule of general applicability, and 

it affects only the applicant that applied 

to the FAA for approval of these features 

on the airplane. 

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 Proposed Special Conditions 

Accordingly, the Administrator of the 

Federal Aviation Administration (FAA) 

proposes the following special 

conditions as part of the type 

certification basis for the Boeing Model 

787–8 airplane. 

In addition to the requirements of 14 

CFR 25.853(a) governing material 

flammability, the following special 

conditions apply: 

The 787 composite fuselage structure must 

be shown to be resistant to flame propagation 

under the fire threat used to develop 14 CFR 

25.856(a). If products of combustion are 

observed beyond the test heat source, they 

must be evaluated and found acceptable. 

Issued in Renton, Washington, on April 18, 

2007. 

Ali Bahrami, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. E7–7840 Filed 4–25–07; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2007–28016; Directorate 

Identifier 2006–NM–227–AD] 

RIN 2120–AA64 

Airworthiness Directives; Learjet 

Model 31, 31A, 35, 35A (C–21A), 36, 

36A, 55, 55B, and 55C Airplanes, and 

Model 45 Airplanes 

AGENCY: Federal Aviation 

Administration (FAA), Department of 

Transportation (DOT). 

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for 

certain Learjet Model 31, 31A, 35, 35A 

(C–21A), 36, 36A, 55, 55B, and 55C 

airplanes, and Model 45 airplanes. This 

proposed AD would require inspecting 

for unsealed gaps on the pylon side of 

the engine firewall and cleaning/sealing 

any unsealed gap; and, for certain 

airplanes, inspecting for unsealed gaps 

of the pylon trailing edge and cleaning/ 

sealing any gap. This proposed AD 

results from a report that unsealed gaps 

(penetration points) of the engine 

firewall were discovered during 

production. We are proposing this AD to 

prevent penetration of flammable 

liquids or fire through the engine 

firewall into the engine pylon, which 

could lead to fire inside the airplane. 

DATES: We must receive comments on 

this proposed AD by June 11, 2007. 

ADDRESSES: Use one of the following 

addresses to submit comments on this 

proposed AD. 

• DOT Docket Web site: Go to 

http://dms.dot.gov and follow the 

instructions for sending your comments 

electronically. 

• Government-wide rulemaking Web 

site: Go to http://www.regulations.gov 

and follow the instructions for sending 

your comments electronically. 

• Mail: Docket Management Facility, 

U.S. Department of Transportation, 400 

Seventh Street, SW., Nassif Building, 

Room PL–401, Washington, DC 20590. 

• Fax: (202) 493–2251. 

• Hand Delivery: Room PL–401 on 

the plaza level of the Nassif Building, 

400 Seventh Street, SW., Washington, 

DC, between 9 a.m. and 5 p.m., Monday 

through Friday, except Federal holidays. 

Contact Learjet, Inc., One Learjet Way, 

Wichita, Kansas 67209–2942, for the 

service information identified in this 

proposed AD. 

FOR FURTHER INFORMATION CONTACT: 

James Galstad, Aerospace Engineer, 

Systems and Propulsion Branch, ACE–

116W, FAA, Wichita Aircraft 

Certification Office, 1801 Airport Road, 

Room 100, Mid-Continent Airport, 

Wichita, Kansas 67209; telephone (316) 

946–4135; fax (316) 946–4107. 

SUPPLEMENTARY INFORMATION: 

Comments Invited 

We invite you to submit any relevant 

written data, views, or arguments 

regarding this proposed AD. Send your 

comments to an address listed in the 

ADDRESSES section. Include the docket 

number ‘‘FAA–2007–28016; Directorate 

Identifier 2006–NM–227–AD’’ at the 

beginning of your comments. We 

specifically invite comments on the 

overall regulatory, economic, 

environmental, and energy aspects of 

the proposed AD. We will consider all 

comments received by the closing date 

and may amend the proposed AD in 

light of those comments. 

We will post all comments we 

receive, without change, to http:// 

dms.dot.gov, including any personal 

information you provide. We will also 

post a report summarizing each 

substantive verbal contact with FAA 

personnel concerning this proposed AD. 

Using the search function of that web 

site, anyone can find and read the 


jlentini on PROD1PC65 with PROPOSALS