Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 43237 

Discussion 

Section 25.701(a) requires that, unless 

the airplane has safe-flight 

characteristics with the flaps or slats 

retracted on one side and extended on 

the other, flap and slat surfaces must be 

synchronized by either a mechanical 

interconnection or any equivalent 

means that has the same integrity. 

Synchronization is interpreted to mean 

that flap movement is symmetrical 

throughout the full range of flap motion. 

Because the lateral-trim function 

intentionally creates asymmetric flap 

motions, the flap-system installation of 

the Model A350–900 airplane does not 

meet the requirement of § 25.701(a) and 

(d). 

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. 

Discussion of Comments 

Notice of proposed special conditions 

no. 25–13–22–SC for Airbus Model 

A350–900 airplanes was published in 

the Federal Register on January 8, 2014 

(79 FR 1339). No comments were 

received, and the special conditions are 

adopted as proposed. 

Applicability 

As discussed above, these special 

conditions apply to Airbus Model 

A350–900 airplanes. Should Airbus 

apply later for a change to the type 

certificate to include another model 

incorporating the same novel or unusual 

design feature, the special conditions 

would apply to that model as well. 

Conclusion 

This action affects only certain novel 

or unusual design features on the Airbus 

Model A350–900 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 typecertification basis for Airbus Model 

A350–900 airplanes: 

Lateral-Trim Function Through 

Differential Flap Setting 

Current airworthiness standards, 

specifically § 25.701, do not contain 

adequate safety standards for this 

airplane design. In lieu of the 

requirements of § 25.701(a) and (d) for 

the lateral-trim function, the following 

special condition are issued: 

1. Airbus must demonstrate that an 

unsafe condition is not created by using 

the flaps asymmetrically. 

2. The degree of acceptable 

asymmetry must be defined and 

justified for all flight phases with 

respect to: 

a. Section 25.701(b) and (c), with the 

worst-case asymmetric flap 

configurations, and 

b. Providing equivalent protection 

against excess asymmetry in the same 

manner as § 25.701 provides to systems 

that are synchronized, or use another 

equivalent means to prevent asymmetry. 

3. This lateral-trim function is a flightcontrol system and therefore must be 

shown to comply with both general 

system requirements as well as general 

flight-control requirements. Therefore, 

the function must be demonstrated not 

to have significant latent failures, where 

practicable. 

Issued in Renton, Washington, on July 9, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–17578 Filed 7–24–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2013–0892; Special 

Conditions No. 25–537–SC] 

Special Conditions: Airbus A350–900 

Airplane; Crashworthiness, Emergency 

Landing Conditions 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for Airbus Model A350–900 

airplanes. These airplanes have a novel 

or unusual design feature associated 

with crashworthiness of carbon-fiberreinforced plastic used in the 

construction of the fuselage. 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: August 25, 2014. 

FOR FURTHER INFORMATION CONTACT: 

Todd Martin, FAA, Airframe/Cabin 

Safety, ANM–115, Transport Airplane 

Directorate, Aircraft Certification 

Service, 1601 Lind Avenue SW., 

Renton, Washington 98057–3356; 

telephone (425) 227–1178; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Background 

On August 25, 2008, Airbus applied 

for a type certificate for their new Model 

A350–900 airplane. Later, Airbus 

requested, and the FAA approved, an 

extension to the application for FAA 

type certification to November 15, 2009. 

The Model A350–900 airplane has a 

conventional layout with twin wingmounted Rolls-Royce Trent XWB 

engines. It features a twin-aisle, 9- 

abreast, economy-class layout, and 

accommodates side-by-side placement 

of LD–3 containers in the cargo 

compartment. The basic Model A350– 

900 airplane configuration 

accommodates 315 passengers in a 

standard two-class arrangement. The 

design cruise speed is Mach 0.85 with 

a maximum take-off weight of 602,000 

lbs. 

Changes in the structural behavior of 

the Airbus Model A350–900 airplane, 

compared to currently certificated 

designs, could degrade the survivability 

of the Model A350–900 airplane 

occupants in crash conditions that are 

within the limits of survivability for 

other designs. 

The airworthiness regulations specify 

no aircraft-level survivable crash 

condition, and metallic aircraft have not 

been designed specifically against 

survivable impact conditions. However, 

the structural behavior of previously 

certificated aircraft in a survivable crash 

event, and the associated limits, are 

considered generally acceptable. It is 

therefore reasonable to expect that a 

design using new materials, such as the 

Model A350–900 airplanes use, should 

be assessed to ensure that the material 

meets the currently accepted level of 

safety. 

The FAA and industry have collected 

a significant amount of experimental 

data, as well as data from crashes of 

transport-category airplanes, that show a 

high occupant-survival rate at verticaldescent velocities up to 30 ft/sec. Based 

on this information, the FAA finds it 

appropriate and necessary for an 


rmajette on DSK2TPTVN1PROD with RULES
43238 Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 

assessment of the Model A350–900 

airplane to span a range of airplane 

vertical-descent speeds up to 30 ft/sec. 

Type Certification Basis 

Under Title 14, Code of Federal 

Regulations (14 CFR) 21.17, Airbus must 

show that the Model A350–900 airplane 

meets the applicable provisions of 14 

CFR part 25, as amended by 

Amendments 25–1 through 25–129. 

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 Model A350–900 airplane 

because of a novel or unusual design 

feature, special conditions are 

prescribed under § 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 Model A350–900 

airplane must comply with the fuel-vent 

and exhaust-emission requirements of 

14 CFR part 34 and the noisecertification requirements of 14 CFR 

part 36. The FAA must issue a finding 

of regulatory adequacy under § 611 of 

Public Law 92–574, the ‘‘Noise Control 

Act of 1972.’’ 

The FAA issues special conditions, as 

defined in 14 CFR 11.19, under § 11.38, 

and they become part of the typecertification basis under § 21.17(a)(2). 

Novel or Unusual Design Features 

The Airbus Model A350–900 airplane 

incorporates the following novel or 

unusual design feature: A fuselage 

fabricated with a combination of carbonfiber-reinforced plastic (CFRP) and 

metallic structure. This is a novel and 

unusual design feature for a large 

transport airplane. Structure fabricated 

from CFRP may behave differently than 

metallic structure in crash conditions 

because of differences in material 

ductility, stiffness, failure modes, and 

energy-absorption characteristics. 

Therefore, the impact-response 

characteristics of the Model A350–900 

airplane must be evaluated to ensure 

that its survivable crashworthiness 

characteristics provide at least the same 

level of safety as those of a similarly 

sized airplane constructed from 

traditional metallic materials. 

No existing regulations adequately 

address this potential difference in 

impact-response characteristics for what 

are considered survivable crash 

conditions. The special conditions are 

necessary to ensure a level of safety 

equivalent to that provided by 14 CFR 

part 25. 

Discussion 

Factors in crash survivability are: 

• Retention of items of mass, 

• maintenance of occupant 

emergency egress paths, 

• maintenance of acceptable 

acceleration and loads experienced by 

the occupants, and 

• maintenance of a survivable 

volume. 

To provide the same level of safety as 

exists with conventional airplane 

construction, Airbus should show that 

the Model A350–900 airplane has 

sufficient crashworthiness capabilities 

under foreseeable survivable impact 

events. To show this, Airbus should 

evaluate the impact-response 

characteristics of the Model A350–900 

airplane to ensure that its 

crashworthiness characteristics are not 

significantly different from those of a 

similarly sized airplane built from 

traditional metallic materials. 

In their evaluation of the Model 

A350–900 airplane response to an 

impact event, Airbus should 

demonstrate that the structural behavior 

is similar to that expected from a 

metallic airframe of a size similar to the 

Model A350–900, or incorporate 

mitigating design features that provide a 

similar level of safety. 

Airbus should demonstrate, either 

through analysis using validated 

analytical tools or by direct-test 

evidence, that the crash dynamics of the 

Model A350–900 fuselage structure 

provides a level of occupant protection 

consistent with previously certificated 

large transport-category airplanes. 

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. 

Discussion of Comments 

Notice of Proposed Special 

Conditions No. 25–13–21–SC for the 

Airbus Model A350–900 airplane was 

published in the Federal Register on 

January 8, 2014 (79 FR 1337). No 

comments were received, and the 

special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions apply to Airbus Model 

A350–900 airplanes. Should Airbus 

apply later for a change to the type 

certificate to include another model 

incorporating the same novel or unusual 

design feature, the special conditions 

would apply to that model as well. 

Conclusion 

This action affects only certain novel 

or unusual design features on the Airbus 

Model A350–900 airplane. 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 typecertification basis for Airbus Model 

A350–900 airplanes. 

The Airbus Model A350–900 airplane 

must provide an equivalent level of 

occupant safety and survivability, to 

that provided by previously certificated 

wide-body transport-category airplanes 

of similar size, under foreseeable 

survivable impact events for the 

following four criteria. To demonstrate 

an equivalent level of occupant safety 

and survivability, the applicant must 

demonstrate that Model A350–900 

airplanes meet the following criteria for 

a range of airplane vertical-descent 

velocities up to 30 ft/sec. 

1. Retention of Items of Mass 

The occupants, i.e., passengers, flight 

attendants, and flightcrew, must be 

protected during the impact event from 

release of seats, overhead bins, and 

other items of mass, due to the impact 

loads and resultant structural 

deformation of the supporting airframe 

and floor structures. The applicant must 

show that loads, due to the impact event 

and resultant structural deformation of 

the supporting airframe and floor 

structure at the interface of the airplane 

structure to seats, overhead bins, and 

other items of mass, are comparable to 

those of previously certificated widebody transports of similar size for the 

range of descent velocities stated above. 

The attachments of these items need not 

be designed for static emergencylanding loads in excess of those defined 

in § 25.561 if impact-response 

characteristics of the Airbus Model 

A350–900 airplane yields load factors at 

the attach points that are comparable to 

those for a previously certificated widebody transport-category airplane. 


rmajette on DSK2TPTVN1PROD with RULES
Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 43239 

2. Maintenance of Acceptable 

Acceleration and Loads Experienced by 

the Occupants 

The applicant must show that the 

impact response characteristics of the 

Airbus Model A350–900 airplane, 

specifically the vertical acceleration 

levels experienced at the seat/floor 

interface, and loads experienced by the 

occupants during the impact events, are 

consistent with those found in 

§ 25.562(b), or with levels expected for 

a previously certificated wide-body 

transport-category airplane for the 

conditions stated above. 

3. Maintenance of a Survivable Volume 

For the conditions stated above, the 

applicant must show that all areas of the 

airplane occupied for takeoff and 

landing provide a survivable volume 

comparable to that of previously 

certificated wide-body transportcategory airplanes of similar size during 

and after the impact event. This means 

that structural deformation will not 

result in infringement of the occupants’ 

normal living space, so that passenger 

survivability will not be significantly 

affected. 

4. Maintenance of Occupant Emergency 

Egress Paths 

The evacuation of occupants must be 

comparable to that from a previously 

certificated wide-body transportcategory airplane of similar size. To 

show this, the applicant must show that 

the suitability of the egress paths, as 

determined following the verticalimpact events, is comparable to the 

suitability of the egress paths of a 

comparable, certificated, wide-body 

transport-category airplane, as 

determined following the same verticalimpact events. 

Issued in Renton, Washington, on July 9, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–17574 Filed 7–24–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2013–0910; Special 

Conditions No. 25–534–SC] 

Special Conditions: Airbus Model 

A350–900 Airplanes; Isolation or 

Protection of the Aircraft Electronic 

System Security From Unauthorized 

Internal Access 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for Airbus Model A350–900 

airplanes. These airplanes will have a 

novel or unusual design feature 

associated with airplane electronic 

system security protection or isolation 

from unauthorized internal access. 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: August 25, 2014. 

FOR FURTHER INFORMATION CONTACT: 

Varun Khanna, FAA, Airplane and 

Flightcrew Interface Branch, ANM–111, 

Transport Airplane Directorate, Aircraft 

Certification Service, 1601 Lind Avenue 

SW., Renton, Washington, 98057–3356; 

telephone (425) 227–1298; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Background 

On August 25, 2008, Airbus applied 

for a type certificate for their new Model 

A350–900 airplane. Later, Airbus 

requested, and the FAA approved, an 

extension to the application for FAA 

type certification to November 15, 2009. 

The Model A350–900 airplane has a 

conventional layout with twin wingmounted Rolls-Royce Trent XWB 

engines. It features a twin-aisle, 9- 

abreast, economy-class layout, and 

accommodates side-by-side placement 

of LD–3 containers in the cargo 

compartment. The basic Model A350– 

900 airplane configuration 

accommodates 315 passengers in a 

standard two-class arrangement. The 

design cruise speed is Mach 0.85 with 

a maximum take-off weight of 602,000 

lbs. 

Contemporary transport-category 

airplanes have both safety-related and 

non-safety-related electronic system 

networks for many operational 

functions. However, electronic system 

network security considerations and 

functions have played a relatively minor 

role in the certification of such systems 

because of the isolation, protection 

mechanisms, and limited connectivity 

between the different networks. 

Type Certification Basis 

Under Title 14, Code of Federal 

Regulations (14 CFR) 21.17, Airbus must 

show that the Model A350–900 airplane 

meets the applicable provisions of 14 

CFR part 25, as amended by 

Amendments 25–1 through 25–129. 

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 Model A350–900 airplane 

because of a novel or unusual design 

feature, special conditions are 

prescribed under § 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 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 Model A350–900 

airplane must comply with the fuel-vent 

and exhaust-emission requirements of 

14 CFR part 34, and the noisecertification requirements of 14 CFR 

part 36. 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, under § 11.38, 

and they become part of the typecertification basis under § 21.17(a)(2). 

Novel or Unusual Design Features 

The Airbus Model A350–900 airplane 

will incorporate the following novel or 

unusual design feature: An electronics 

network system architecture that is 

novel or unusual for commercial 

transport airplanes, and that introduces 

potential security risks and 

vulnerabilities not addressed in current 

regulations and airplane-level or 

system-level safety assessment methods. 

Discussion 

The Airbus Model A350–900 airplane 

architecture is novel or unusual for 

commercial transport airplanes because 

it allows connection to previously 

isolated data networks connected to 

systems that perform functions required 


rmajette on DSK2TPTVN1PROD with RULES