Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 43233 

aluminum fuselage in an inaccessible 

in-flight fire scenario is understood 

based on service history and extensive 

intermediate and large-scale fire testing. 

The fuselage itself does not contribute to 

in-flight fire propagation. This may not 

be the case for an all-composite 

fuselage. The existing regulations do not 

adequately address protection against an 

in-flight fire for an all-composite 

fuselage. These special conditions are 

necessary to ensure a level of safety 

equivalent to that provided by existing 

regulations. 

Type Certification Basis 

Under the provisions of Title 14, Code 

of Federal Regulations (14 CFR) 21.17, 

Learjet Inc. must show that the Model 

LJ–200 airplane meets the applicable 

provisions of part 25, as amended by 

Amendments 25–1 through 25–127, and 

14 CFR part 26, as amended by 

Amendment 26–1 through 26–2. 

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 LJ–200 airplane 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 Model LJ–200 airplane 

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 § 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 Model LJ–200 airplane will 

incorporate the following novel or 

unusual design features: The fuselage 

will be fabricated using composite 

materials instead of conventional 

aluminum. 

Discussion 

The Model LJ–200 airplane 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. 

Despite the major change from 

aluminum to composite material for the 

fuselage, the Model LJ–200 airplane 

must have in-flight survivability such 

that the composite fuselage does not 

propagate a fire. A methodology for 

assessing the in-flight fire survivability 

of an all-composite fuselage is therefore 

needed. 

The FAA believes that one way to 

assess the survivability within the cabin 

of the Model LJ–200 airplane is to 

conduct large-scale tests. These largescale tests would use a mock-up of a 

Model LJ–200 airplane fuselage skin/

structure section of sufficient size to 

assess any tendency for fire propagation. 

The fire threat used to represent the 

realistic ignition source in the airplane 

would consist of a 4′′ x 4′′ x 9′′ 

polyurethane foam block and 10 ml of 

Heptane. This ignition source provides 

approximately three minutes of flame 

time and would be positioned at various 

points and orientations within the 

mocked up installation to impinge on 

those areas of the fuselage considered to 

be most crucial. 

This fire threat was established based 

on an assessment of a range of potential 

ignition sources, coupled with possible 

contamination of materials. The FAA 

considers this a severe fire threat, 

encompassing a variety of scenarios. 

However, should ignition or fire sources 

of a greater severity be identified, these 

special conditions or the method of 

compliance would need to be modified 

in order to take the more severe threat 

into account. 

Despite the major change from 

aluminum to composite material for the 

fuselage, the Model LJ–200 must have 

in-flight fire survivability such that the 

composite fuselage is no worse than that 

of a similar aluminum structure. 

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. 25–14–01–SC for the Learjet Inc. 

Model LJ–200–1A10 airplane was 

published in the Federal Register on 

February 7, 2014 (79 FR 7406). No 

comments were received, and the 

special conditions are adopted as 

proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to the Model 

LJ–200 airplane. Should Learjet Inc. 

apply at a later date 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 one model 

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 Learjet Inc. Model LJ–200– 

1A10 airplane. 

Composite Fuselage In-Flight Fire/

Flammability Resistance. The Learjet 

Inc. Model LJ–200 composite fuselage 

structure must be shown to be resistant 

to flame propagation under the fire 

threat used to develop § 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 June 6, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–17518 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–2013–0904; Special 

Conditions No. 25–542–SC] 

Special Conditions: Airbus Model 

A350–900 Series Airplane; Electronic 

Flight-Control System: LateralDirectional and Longitudinal Stability, 

and Low-Energy Awareness 

AGENCY: Federal Aviation 

Administration (FAA), DOT. 

ACTION: Final special conditions. 

SUMMARY: These special conditions are 

issued for Airbus Model A350–900 

series airplanes. These airplanes will 


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43234 Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 

have a novel or unusual design feature 

associated with lateral-directional and 

longitudinal stability, and low-energy 

awareness. 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: Joe 

Jacobsen, FAA, Airplane and Flightcrew 

Interface Branch, ANM–111, Transport 

Airplane Directorate, Aircraft 

Certification Service, 1601 Lind Avenue 

SW., Renton, Washington 98057–3356; 

telephone (425) 227–2011; facsimile 

(425) 227–1320. 

SUPPLEMENTARY INFORMATION: 

Background 

On August 25, 2008, Airbus applied 

for a type certificate for their new Model 

A350–900 series 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 series airplane 

has a conventional layout with twin 

wing-mounted 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. 

Lateral-Directional Static Stability 

The electronic flight-control system 

(EFCS) on the A350 airplane, like its 

predecessors the A320, A330, A340, and 

A380 airplanes, contains fly-by-wire 

control laws that can result in neutral 

lateral-directional static stability; 

therefore, the conventional 

requirements in the regulations are not 

met. 

Positive static directional stability is 

defined as the tendency to recover from 

a skid with the rudder free. Positive 

static lateral stability is defined as the 

tendency to raise the low wing in a 

sideslip with the aileron controls free. 

These control criteria are intended to 

accomplish the following: 

1. Provide additional cues of 

inadvertent sideslips and skids through 

control-force changes. 

2. Ensure that short periods of 

unattended operation do not result in 

any significant changes in yaw or bank 

angle. 

3. Provide predictable roll and yaw 

response. 

4. Provide an acceptable level of pilot 

attention (workload) to attain and 

maintain a coordinated turn. 

The Flight Test Harmonization 

Working Group has recommended a rule 

and advisory-material change for 

§ 25.177, static lateral-directional 

stability. This harmonized text will form 

the basis for these special conditions. 

Longitudinal Static Stability 

Static longitudinal stability on 

airplanes with mechanical links to the 

pitch-control surface means that a pull 

force on the controller will result in a 

reduction in speed relative to the trim 

speed, and a push force will result in a 

higher speed than the trim speed. 

Longitudinal stability is required by the 

regulations for the following reasons: 

1. Speed-change cues are provided to 

the pilot through increased and 

decreased forces on the controller. 

2. Short periods of unattended control 

of the airplane do not result in 

significant changes in attitude, airspeed, 

or load factor. 

3. A predictable pitch response is 

provided to the pilot. 

4. An acceptable level of pilot 

attention (workload) to attain and 

maintain trim speed and altitude is 

provided to the pilot. 

5. Longitudinal stability provides gust 

stability. 

The pitch-control movement of the 

sidestick on the A350 airplane is 

designed to be a normal load factor or 

‘‘g’’ command that results in an initial 

movement of the elevator surface to 

attain the commanded load factor, 

which is then followed by integrated 

movement of the stabilizer and elevator 

to automatically trim the airplane to a 

neutral, 1g, stick-free stability. The 

flight path commanded by the initial 

sidestick input will remain stick-free 

until the pilot provides another 

command. This control function is 

applied during ‘‘normal’’ control law 

within the speed range from initiation of 

the angle-of-attack protection limit, 

Vαprot, to VMO/MMO. Once outside this 

speed range, the control laws introduce 

the conventional longitudinal static 

stability as described above. 

As a result of neutral static stability, 

the A350 airplane does not meet the 

requirements of 14 CFR part 25 for static 

longitudinal stability. 

Low Energy Awareness 

Past experience on airplanes fitted 

with a flight-control system providing 

neutral longitudinal stability shows 

insufficient feedback cues to the pilot of 

excursion below normal operational 

speeds. The maximum-angle-of-attack 

protection system limits the airplane 

angle of attack and prevents stall during 

normal operating speeds, but this 

system is not sufficient to prevent stall 

at low-speed excursions below normal 

operational speeds. Until intervention, 

the pilot has no stability cues because 

the aircraft remains trimmed. 

Additionally, feedback from the 

pitching moment, due to thrust 

variation, is reduced by the flightcontrol laws. Recovery from a low-speed 

excursion may become hazardous when 

the low-speed situation is associated 

with a low altitude, and with the 

engines at low thrust or with 

performance-limiting conditions. 

Type Certification Basis 

Under Title 14, Code of Federal 

Regulations (14 CFR) 21.17, Airbus must 

show that the Model A350–900 series 

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 series 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 series 

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 series 

airplane will incorporate the following 

novel or unusual design features: A 

flight-control design feature within the 

normal operational envelope in which 

sidestick deflection in the roll axis 

commands roll rate; an operational 


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Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 43235 

design that does not comply with the 

static longitudinal stability 

requirements of §§ 25.171, 25.173, and 

25.175; and a low-energy state where 

recovery may become hazardous when 

associated with both a low altitude and 

performance-limiting conditions. 

Discussion 

In the absence of positive lateral 

stability, the curve of lateral controlsurface deflections against sideslip 

angle should be in a conventional sense, 

and reasonably in harmony with rudder 

deflection during steady-heading 

sideslip maneuvers. 

Since conventional relationships 

between stick forces and control-surface 

displacements do not apply to the 

‘‘load-factor command’’ flight-control 

system on the A350 airplane, 

longitudinal stability characteristics 

should be evaluated by assessing the 

airplane’s handling qualities during 

simulator and flight-test maneuvers 

appropriate to operation of the airplane. 

Airbus may accomplish this by using 

the Handling Qualities Rating Method 

presented in Appendix 5 of the Flight 

Test Guide, AC 25–7C, or an acceptable 

alternative method. Important 

considerations are as follows: 

a. Adequate speed control without 

excessive pilot workload, 

b. Acceptable high- and low-speed 

protection, and 

c. Provision for adequate cues to the 

pilot of significant speed excursions 

beyond VMO/MMO, and low-speedawareness flight conditions. 

The airplane should provide adequate 

awareness cues to the pilot of a lowenergy (low speed/low thrust/low 

height) state to ensure that the airplane 

retains sufficient energy to recover 

when flight-control laws provide neutral 

longitudinal stability significantly 

below the normal operating speeds. This 

may be accomplished as follows: 

a. Adequate low-speed/low-thrust 

cues at low altitude may be provided by 

a strong, positive, static, stability force 

gradient (1 pound per 6 knots applied 

through the sidestick), or 

b. The low-energy awareness may be 

provided by an appropriate warning 

with the following characteristics: 

i. It should be unique, unambiguous, 

and unmistakable. 

ii. It should be active at appropriate 

altitudes and in appropriate 

configurations (i.e., at low altitude, in 

the approach and landing 

configurations). 

iii. It should be sufficiently timely to 

allow recovery to a stabilized flight 

condition inside the normal flight 

envelope, while maintaining the desired 

flight path and without entering the 

flight controls angle-of-attack protection 

mode. 

iv. It should not be triggered during 

normal operation, including operation 

in moderate turbulence for 

recommended maneuvers at 

recommended speeds. 

v. It should not be cancelable by the 

pilot other than by achieving a higherenergy state. 

vi. There should be an adequate 

hierarchy among the various warnings 

so that the pilot is not confused and led 

to take inappropriate recovery action if 

multiple warnings occur. 

Global energy awareness and nonnuisance of low-energy cues should be 

evaluated by simulator and flight tests 

in the whole take-off and landing 

altitude range for which certification is 

requested. This would include all 

relevant combinations of weight, centerof-gravity position, configuration, 

airbrakes position, and available thrust, 

including reduced and de-rated take-off 

thrust operations and engine-failure 

cases. A sufficient number of tests 

should be conducted, allowing the level 

of energy awareness and the effects of 

energy-management errors to be 

assessed. 

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. 25–13–14–SC for Airbus 

Model A350–900 series airplanes was 

published in the Federal Register on 

January 14, 2014 (79 FR 2384). 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 series 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 series 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 series airplanes. 

(1) Electronic Flight-Control System: 

Lateral-Directional and Longitudinal 

Stability, and Low-Energy Awareness. 

In lieu of the requirements of §§ 25.171, 

25.173, 25.175 and 25.177, the following 

special conditions apply: 

(a) The airplane must be shown to 

have suitable static lateral, directional, 

and longitudinal stability in any 

condition normally encountered in 

service, including the effects of 

atmospheric disturbance. The showing 

of suitable static lateral, directional, and 

longitudinal stability must be based on 

the airplane handling qualities, 

including pilot workload and pilot 

compensation, for specific test 

procedures during the flight-test 

evaluations. 

(b) The airplane must provide 

adequate awareness to the pilot of a 

low-energy (low speed/low thrust/low 

height) state when fitted with flightcontrol laws presenting neutral 

longitudinal stability significantly 

below the normal operating speeds. 

‘‘Adequate awareness’’ means warning 

information must be provided to alert 

the crew of unsafe operating conditions 

and to enable them to take appropriate 

corrective action. 

(c) The static directional stability (as 

shown by the tendency to recover from 

a skid with the rudder free) must be 

positive for any landing gear and flap 

position, and symmetrical power 

condition, at speeds from 1.13 VSR1, up 

to VFE, VLE, or VFC/MFC (as appropriate). 

(d) The static lateral stability (as 

shown by the tendency to raise the low 

wing in a sideslip with the aileron 

controls free) for any landing gear and 

wing-flap position, and symmetric 

power condition, may not be negative at 

any airspeed (except that speeds higher 

than VFE need not be considered for 

wing-flaps-extended configurations, nor 

speeds higher than VLE for landing-gearextended configurations) in the 

following airspeed ranges: 

(i) From 1.13 VSR1 to VMO/MMO. 

(ii) From VMO/MMO to VFC/MFC, 

unless the divergence is – 

(1) Gradual; 

(2) Easily recognizable by the pilot; 

and 

(3) Easily controllable by the pilot. 


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43236 Federal Register / Vol. 79, No. 143 / Friday, July 25, 2014 / Rules and Regulations 

(e) In straight, steady sideslips over 

the range of sideslip angles appropriate 

to the operation of the airplane, but not 

less than those obtained with one-half of 

the available rudder-control movement 

(but not exceeding a rudder-control 

force of 180 pounds), rudder-control 

movements and forces must be 

substantially proportional to the angle 

of sideslip in a stable sense; and the 

factor of proportionality must lie 

between limits found necessary for safe 

operation. This requirement must be 

met for the configurations and speeds 

specified in paragraph (c) of this 

section. 

(f) For sideslip angles greater than 

those prescribed by paragraph (e) of this 

section, up to the angle at which full 

rudder control is used or a ruddercontrol force of 180 pounds is obtained, 

the rudder-control forces may not 

reverse, and increased rudder deflection 

must be needed for increased angles of 

sideslip. Compliance with this 

requirement must be shown using 

straight, steady sideslips, unless full 

lateral-control input is achieved before 

reaching either full rudder-control input 

or a rudder-control force of 180 pounds; 

a straight, steady sideslip need not be 

maintained after achieving full lateralcontrol input. 

This requirement must be met at all 

approved landing-gear and wing-flap 

positions for the range of operating 

speeds and power conditions 

appropriate to each landing-gear and 

wing-flap position with all engines 

operating. 

Issued in Renton, Washington, on July 9, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–17575 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–2013–0911; Special 

Conditions No. 25–539–SC] 

Special Conditions: Airbus Model 

A350–900 Airplanes; Lateral-Trim 

Function Through Differential Flap 

Setting 

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 a lateral-trim function 

that deploys flaps asymmetrically for 

airplane lateral-trim control. This 

function replaces the traditional method 

of providing airplane lateral trim over a 

small range through flap and aileron 

mechanical rigging. 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: 

Robert C. Jones, FAA, Propulsion and 

Mechanical Systems, ANM–112, 

Transport Airplane Directorate, Aircraft 

Certification Service, 1601 Lind Avenue 

SW., Renton, Washington 98057–3356; 

telephone (425) 227–1234; 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. 

On conventional airplanes, small, 

lateral, airplane asymmetries typically 

have been addressed through flap and 

aileron rigging (e.g., using shims). On 

Model A350–900 airplanes, an order for 

asymmetric flap deployment will be 

computed by the primary flight-control 

system as a function of the aileron 

position. The current airworthiness 

standards do not contain adequate 

safety standards for asymmetric use of 

the flaps for Airbus Model A350–900 

airplanes. Special conditions are needed 

to account for the aspects of a function 

used to command an intended flap 

asymmetry. The lateral-trim function is 

intended to be performed once during 

climb and once during cruise to 

compensate for airplane small lateral 

asymmetries. 

The lateral-trim function is not a trimcontrol system in the conventional 

sense as it has no pilot interface and is 

not governed by Title 14, Code of 

Federal Regulations (14 CFR) 25.677. 

Some fly-by-wire airplanes have no 

pilot-operated lateral trim at all. The 

lateral-trim function is simply an 

additional fly-by-wire flight-control 

function that nulls small roll 

asymmetries in certain flight phases 

with small, asymmetric flap 

deployments. Although the function 

operates under normal conditions 

within the small range of the traditional 

rigging, failure cases may result in a 

significant out-of-range asymmetric flap 

condition. An asymmetry threshold 

protects the system against excessive 

flap asymmetry. 

Type Certification Basis 

Under 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 § 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 features: The 

asymmetric use of flaps to address 

lateral trim, which is not adequately 

addressed by § 25.701. 


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