32636 Federal Register / Vol. 79, No. 109 / Friday, June 6, 2014 / Rules and Regulations 

Electronic Flight Control System: 

Control Surface Awareness and Mode 

Annunciation 

■ 1. In addition to the requirements of 

§§ 25.143, 25.671, and 25.672, the 

following requirements apply: 

a. The system design must ensure that 

the flightcrew is made suitably aware 

whenever the primary control means 

nears the limit of control authority. 

Note: The term ‘‘suitably aware’’ indicates 

annunciations provided to the flightcrew are 

appropriately balanced between nuisance 

and that necessary for crew awareness. 

b. If the design of the flight control 

system has multiple modes of operation, 

a means must be provided to indicate to 

the flightcrew any mode that 

significantly changes or degrades the 

normal handling or operational 

characteristics of the airplane. 

Issued in Renton, Washington, on April 22, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–13240 Filed 6–5–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2013–1039; Notice No. 25– 

547–SC] 

Special Conditions: Bombardier 

Aerospace, Models BD–500–1A10 and 

BD–500–1A11 Series Airplanes; Flight 

Envelope Protection: Normal Load 

Factor (g) Limiting 

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 an electronic 

flight control system that prevents the 

pilot from inadvertently or intentionally 

exceeding the positive or negative 

airplane limit load factor. 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: July 7, 2014. 

FOR FURTHER INFORMATION CONTACT: Joe 

Jacobsen, FAA, Airplane and Flight 

Crew Interface Branch, ANM–111, 

Transport Airplane Directorate, Aircraft 

Certification Service, 1601 Lind Avenue 

SW., Renton, Washington 98057–3356; 

telephone 425–227–2011; facsimile 

425–227–1149. 

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. 

The design of the electronic flight 

control system for the CSeries airplanes 

incorporates normal load factor limiting 

on a full time basis that prevents the 

flightcrew from inadvertently or 

intentionally exceeding the positive or 

negative airplane limit load factor. This 

feature is considered novel and unusual 

in that the current regulations do not 

provide standards for maneuverability 

and controllability evaluations for such 

systems. 

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 § 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 use a flyby-wire electronic flight control system 

(EFCS). This system provides an 

electronic interface between the pilot’s 

flight controls and the flight control 

surfaces for both normal and failure 

states; and it generates the actual surface 

commands that provide for stability 

augmentation and control about all 

three airplane axes. 

The design of the EFCS incorporates 

the following novel or unusual design 

feature: Normal load factor limiting on 

a full-time basis that will prevent the 

flight crew from inadvertently or 

intentionally exceeding the positive or 

negative airplane limit load factor. This 

feature is considered novel or unusual 

because the current regulations do not 

provide standards for maneuverability 

and controllability evaluations for such 

systems. Therefore, special conditions 

are needed to ensure adequate 

maneuverability and controllability 

when using this design feature. 

Discussion 

Title 14, Code of Federal Regulations, 

part 25 does not specify requirements or 

policy for demonstrating maneuver 

control that impose any handling 

qualities requirements beyond the 

design limit structural loads. 

Nevertheless, some pilots have become 

accustomed to the availability of this 

excess maneuver capacity in case of 

extreme emergency such as upset 

recoveries or collision avoidance. 

As with previous fly-by-wire 

airplanes, the FAA has no regulatory or 

safety reason to prohibit a design for an 

electronic flight control system with 

load factor limiting. It is possible that 

pilots accustomed to this feature feel 

more freedom in commanding full-stick 

displacement maneuvers because of the 

following: 

• Knowledge that the limit system 

will protect the structure, 

• Low stick force/displacement 

gradients, 

• Smooth transition from pilot 

elevator control to limit control. 

These special conditions will ensure 

adequate maneuverability and 

controllability when using this design 

feature. 

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Federal Register / Vol. 79, No. 109 / Friday, June 6, 2014 / Rules and Regulations 32637 

The normal load factor limit on the 

CSeries airplanes is unique in that 

traditional airplanes with conventional 

flight control systems (mechanical 

linkages) are limited in the pitch axis 

only by the elevator surface area and 

deflection limit. The elevator control 

power is normally derived for adequate 

controllability and maneuverability at 

the most critical longitudinal pitching 

moment. The result is that traditional 

airplanes have a significant portion of 

the flight envelope wherein 

maneuverability in excess of limit 

structural design values is possible. 

These special conditions for the 

CSeries airplanes supplement the 

applicable regulations, including 

§ 25.143, to accommodate the unique 

features of the flight envelope limiting 

systems, and establish an equivalent 

level of safety to the existing 

regulations. 

Discussion of Comments 

Notice of proposed special conditions 

No. 25–13–38–SC for the Bombardier 

CSeries airplanes was published in the 

Federal Register on December 11, 2013 

(78 FR 75285). No comments were 

received, and the special conditions are 

adopted as proposed. 

Applicability 

As discussed above, these special 

conditions are applicable to the Models 

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 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 two 

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 the Bombardier 

Aerospace Models BD–500–1A10 and 

BD–500–1A11 series airplanes. 

Flight Envelope Protection: Normal 

Load Factor (g) Limiting 

■ 1. To meet the intent of adequate 

maneuverability and controllability 

required by § 25.143(a), and in addition 

to the requirements of § 25.143(a) and in 

the absence of other limiting factors, the 

following special conditions based on 

§ 25.333(b) apply: 

a. The positive limiting load factor 

must not be less than: 

(1) 2.5g for the normal state of the 

electronic flight control system with the 

high lift devices retracted. 

(2) 2.0g for the normal state of the 

electronic flight control system with the 

high lift devices extended. 

b. The negative limiting load factor 

must be equal to or more negative than: 

(1) Minus 1.0g for the normal state of 

the electronic flight control system with 

the high lift devices retracted. 

(2) 0.0g for the normal state of the 

electronic flight control system with 

high lift devices extended. 

c. Maximum reachable positive load 

factor wings level may be limited by the 

characteristics of the electronic flight 

control system or flight envelope 

protections (other than load factor 

protection) provided that: 

(1) The required values are readily 

achievable in turns, and 

(2) That wings level pitch up is 

satisfactory. 

d. Maximum achievable negative load 

factor may be limited by the 

characteristics of the electronic flight 

control system or flight envelope 

protections (other than load factor 

protection) provided that: 

(1) Pitch down responsiveness is 

satisfactory, and 

(2) From level flight, 0g is readily 

achievable or alternatively, a 

satisfactory trajectory change is readily 

achievable at operational speeds. For 

the FAA to consider a trajectory change 

as satisfactory, the applicant should 

propose and justify a pitch rate that 

provides sufficient maneuvering 

capability in the most critical scenarios. 

e. Compliance demonstration with the 

above requirements may be performed 

without ice accretion on the airframe. 

These special conditions do not 

impose an upper bound for the normal 

load factor limit, nor do they require 

that the limit exist. If the limit is set at 

a value beyond the structural design 

limit maneuvering load factor ‘‘n’’ of 

§§ 25.333(b) and 25.337(b) and (c), there 

should be a very obvious positive tactile 

feel built into the controller so that it 

serves as a deterrent to inadvertently 

exceeding the structural limit. 

Issued in Renton, Washington, on April 22, 

2014. 

Jeffrey E. Duven, 

Manager, Transport Airplane Directorate, 

Aircraft Certification Service. 

[FR Doc. 2014–13241 Filed 6–5–14; 8:45 am] 

BILLING CODE 4910–13–P 

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 25 

[Docket No. FAA–2013–1040; Notice No. 25– 

548–SC] 

Special Conditions: Bombardier 

Aerospace, Models BD–500–1A10 and 

BD–500–1A11 Series Airplanes; Flight 

Envelope Protection: General Limiting 

Requirements 

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 a new control 

architecture and a full digital flight 

control system that provides flight 

envelope protections. 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: July 7, 2014. 

FOR FURTHER INFORMATION CONTACT: Joe 

Jacobsen, FAA, Airplane and Flight 

Crew Interface Branch, ANM–111, 

Transport Airplane Directorate, Aircraft 

Certification Service, 1601 Lind Avenue 

SW., Renton, Washington 98057–3356; 

telephone 425–227–2011; facsimile 

425–227–1149. 

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 

mstockstill on DSK4VPTVN1PROD with RULES