Document ID: FAA-2015-0426-0003
Agency: faa
Document Type: Rule
Title: Special Conditions: Bombardier Aerospace Incorporated, Models BD-500-1A10 and BD-500-1A11 Series Airplanes; Electronic Flight-Control System (EFCS): Pitch- and Roll-Limiting Functions
Posted Date: 2015-06-25T04:00Z

[Federal Register Volume 80, Number 122 (Thursday, June 25, 2015)]
[Rules and Regulations]
[Pages 36470-36471]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-15545]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2015-0426; Special Conditions No. 25-576-SC]

Special Conditions: Bombardier Aerospace Incorporated, Models BD-
500-1A10 and BD-500-1A11 Series Airplanes; Electronic Flight-Control 
System (EFCS): Pitch-and Roll-Limiting Functions

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Bombardier 
Aerospace Model BD-500-1A10 and BD-500-1A11 series airplanes. These 
airplanes will have a novel or unusual design feature associated with a 
fly-by-wire EFCS that limits pitch- and roll-limiting functions to 
prevent the airplane from attaining certain pitch attitudes and roll 
angles. This system generates the actual surface commands that provide 
for stability augmentation and flight control for all three airplane 
axes (longitudinal, lateral, and directional). 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 July 27, 2015.

FOR FURTHER INFORMATION CONTACT: Joe Jacobsen, FAA, Standardization 
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 Model BD-500-1A10 and

[[Page 36471]]

BD-500-1A11 series airplanes (hereafter collectively referred to as 
``CSeries''). Bombardier later applied for, and was granted, an 
extension of time for the type certificate, which changed the effective 
application date to December 31, 2011. The CSeries airplanes are swept-
wing monoplanes with an aluminum alloy fuselage, sized for 5-abreast 
seating. Passenger capacity is 110 for the Model BD-500-1A10 and 125 
for the Model BD-500-1A11. The airplanes are powered by two underwing 
Pratt and Whitney PW1524G ultra-high bypass, geared, turbofan engines. 
Maximum takeoff weight is 131,000 pounds for the Model BD-500-1A10 and 
144,000 pounds for the Model BD-500-1A11. The CSeries airplanes will 
have a fly-by-wire EFCS.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14 
CFR) 21.17, Bombardier Aerospace must show that the CSeries airplane 
meets the applicable provisions of 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 Bombardier CSeries airplanes 
because of a novel or unusual design feature, special conditions are 
prescribed under the provisions of Sec.  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, these special conditions would also 
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special 
conditions, the Bombardier CSeries 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. The FAA must issue 
a finding of regulatory adequacy under Sec.  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 Sec.  11.38, and they become part of the type-
certification basis under Sec.  21.17(a)(2).

Novel or Unusual Design Features

    The Bombardier CSeries airplane will incorporate the following 
novel or unusual design feature: Fly-by-wire EFCS that will limit pitch 
and roll functions to prevent the airplane from attaining certain pitch 
attitudes and roll angles greater than plus or minus 65 degrees, and 
positive spiral stability introduced for roll angles greater than 30 
degrees at speeds below VMO/MMO. This system 
generates the actual surface commands that provide for stability 
augmentation and flight control for all three airplane axes 
(longitudinal, lateral, and directional).

Discussion

    Part 25 does not specifically relate to flight characteristics 
associated with fixed attitude limits. Bombardier proposes to implement 
on the CSeries airplanes pitch and roll attitude-limiting functions via 
the EFCS normal mode. This will prevent the airplane from attaining 
certain pitch attitudes and roll angles greater than plus or minus 65 
degrees. In addition, positive spiral stability, introduced for roll 
angles greater than 30 degrees at speeds below VMO/
MMO, and spiral stability characteristics, must not require 
excessive pilot strength to achieve bank angles up to the bank-angle 
limit.
    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. 25-15-02-SC for the 
Bombardier Model BD-500-1A10 and BD-500-1A11 series airplanes was 
published in the Federal Register on February 27, 2015 (80 FR 10632). 
No substantive comments were received, and the special conditions are 
adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Bombardier CSeries airplane. Should Bombardier Aerospace apply later 
for a change to the type certificate to include another model 
incorporating the same or similar 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 Bombardier CSeries 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 CSeries airplanes.
    In addition to Sec.  25.143, the following requirements apply to 
the EFCS pitch- and roll-limiting functions:
    1. The pitch-limiting function must not impede normal maneuvering 
for pitch angles up to the maximum required for normal maneuvering, 
including a normal, all-engines-operating takeoff, plus a suitable 
margin to allow for satisfactory speed control.
    2. The pitch- and roll-limiting functions must not restrict or 
prevent attaining pitch attitudes necessary for emergency maneuvering, 
or roll angles up to 65 degrees. Spiral stability, which is introduced 
above 30 degrees roll angle, must not require excessive pilot strength 
to achieve these roll angles. Other protections, which further limit 
the roll capability under certain extreme angle-of-attack, attitude, or 
high-speed conditions, are acceptable, as long as they allow at least 
45 degrees of roll capability.
    3. A lower limit of roll is acceptable beyond the overspeed warning 
if it is possible to recover the airplane to the normal flight envelope 
without undue difficulty or delay.

    Issued in Renton, Washington, on June 17, 2015.
Jeffrey E. Duven,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-15545 Filed 6-24-15; 8:45 am]
 BILLING CODE 4910-13-P