[Federal Register Volume 78, Number 102 (Tuesday, May 28, 2013)]
[Rules and Regulations]
[Pages 31838-31839]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2013-12536]



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.


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.

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.



    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

[[Page 31839]]

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


    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.


    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.


    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 

    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 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 
[FR Doc. 2013-12536 Filed 5-24-13; 8:45 am]