[Federal Register Volume 78, Number 102 (Tuesday, May 28, 2013)]
[Rules and Regulations]
[Pages 31838-31839]
[FR Doc No: 2013-12536]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2012-1332; Special Conditions No. 25-492-SC]

Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight
Envelope Protection: General Limiting Requirements

AGENCY:  Federal Aviation Administration (FAA), DOT.

ACTION:  Final special conditions.

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SUMMARY:  These special conditions are issued for the Embraer S.A.
Model EMB-550 airplane. This airplane will have a novel or unusual
design feature, specifically new control architecture and a full
digital flight control system which 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: June 27, 2013.

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<PHONE_NUMBER>; facsimile<PHONE_NUMBER>.

SUPPLEMENTARY INFORMATION:

Background

    On May 14, 2009, Embraer S.A. applied for a type certificate for
their new Model EMB-550 airplane. The Model EMB-550 airplane is the
first of a new family of jet airplanes designed for corporate flight,
fractional, charter, and private owner operations. The aircraft has a
conventional configuration with low wing and T-tail empennage. The
primary structure is metal with composite empennage and control
surfaces. The Model EMB-550 airplane is designed for 8 passengers, with
a maximum of 12 passengers. It is equipped with two Honeywell HTF7500-E
medium bypass ratio turbofan engines mounted on aft fuselage pylons.
Each engine produces approximately 6,540 pounds of thrust for normal
takeoff. The primary flight controls consist of hydraulically powered
fly-by-wire elevators, aileron and rudder, controlled by the pilot or
copilot sidestick.
    Embraer S.A. has developed comprehensive flight envelope protection
features integral to the electronic flight control system design. These
flight envelope protection features include limitations on angle-of-
attack, normal load factor, bank angle, pitch angle, and speed. To
accomplish this flight-envelope-limiting, a significant change (or
multiple changes) occurs in the control laws of the electronic flight
control system as the limit is approached or exceeded. When failure
states occur in the electronic flight control system, flight envelope
protection features can likewise either be modified, or in some cases,
eliminated. The current regulations were not written with these
comprehensive flight-envelope-limiting systems in mind.

Type Certification Basis

    Under the provisions of Title 14, Code of Federal Regulations (14
CFR) 21.17, Embraer S.A. must show that the Model EMB-550 airplane
meets the applicable provisions of part 25, as amended by Amendments
25-1 through 25-127 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 Model EMB-550 airplane 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, the special conditions would also
apply to the other model under Sec.  21.101.
    In addition to the applicable airworthiness regulations and special
conditions, the Model EMB-550 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 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 Model EMB-550 airplane will incorporate the following novel or
unusual design features: new control

architecture and a full digital flight control system which provides
comprehensive flight envelope protections.

Discussion

    The applicable airworthiness regulation in this instance is 14 CFR
Sec.  25.143. The purpose of Sec.  25.143 is to verify that any
operational maneuvers conducted within the operational envelope can be
accomplished smoothly with average piloting skill and without exceeding
any structural limits. The pilot should be able to predict the airplane
response to any control input. During the course of the flight test
program, the pilot determines compliance with Sec.  25.143 through
primarily qualitative methods. During flight test, the pilot should
evaluate all of the following:
     The interface between each protection function,
     Transitions from one mode to another,
     The aircraft response to intentional dynamic maneuvering,
whenever applicable, through dedicated maneuvers,
     General controllability assessment,
     High speed characteristics, and
     High angle-of-attack.
    Section Sec.  25.143, however, does not adequately ensure that the
novel or unusual features of the Model EMB-550 airplane will have a
level of safety equivalent to that of existing standards. This special
condition is therefore required to accommodate the the flight-envelope-
limiting systems in the Model EMB-550 airplane. The additional safety
standards in this special condition will ensure a level of safety
equivalent to that of existing standards.

Discussion of Comments

    Notice of proposed special conditions number 25-19-SC for the
Embraer S.A. Model EMB-550 airplanes was published in the Federal
Register on January 24, 2013 (78 FR 5148). No comments were received,
and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the
Model EMB-550 airplane. Should Embraer S.A. 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

0
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 Embraer S.A. Model EMB-550 airplanes.
    1. General Limiting Requirements:
    a. Onset characteristics of each envelope protection feature must
be smooth, appropriate to the phase of flight and type of maneuver, and
not in conflict with the ability of the pilot to satisfactorily change
airplane flight path, speed, or attitude as needed.
    b. Limit values of protected flight parameters (and if applicable,
associated warning thresholds) must be compatible with the following:
    i. Airplane structural limits,
    ii. Required safe and controllable maneuvering of the airplane, and
    iii. Margins to critical conditions. Unsafe flight characteristics/
conditions must not result if dynamic maneuvering, airframe and system
tolerances (both manufacturing and in-service), and non-steady
atmospheric conditions, in any appropriate combination and phase of
flight, can produce a limited flight parameter beyond the nominal
design limit value.
    c. The airplane must be responsive to intentional dynamic
maneuvering to within a suitable range of the parameter limit. Dynamic
characteristics such as damping and overshoot must also be appropriate
for the flight maneuver and limit parameter in question.
    d. When simultaneous envelope limiting is engaged, adverse coupling
or adverse priority must not result.
    2. Failure States: Electronic flight control system failures
(including sensor) must not result in a condition where a parameter is
limited to such a reduced value that safe and controllable maneuvering
is no longer available. The crew must be alerted by suitable means if
any change in envelope limiting or maneuverability is produced by
single or multiple failures of the electronic flight control system not
shown to be extremely improbable.

    Issued in Renton, Washington, on May 21, 2013.
Jeff Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 2013-12536 Filed 5-24-13; 8:45 am]
BILLING CODE 4910-13-P