
[Federal Register Volume 78, Number 102 (Tuesday, May 28, 2013)]
[Rules and Regulations]
[Pages 31836-31838]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-12535]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2012-1301; Special Conditions No. 25-491-SC]


Special Conditions: Embraer S.A., Model EMB-550 Airplane, Dive 
Speed Definition With Speed Protection System

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 when compared to the state of technology envisioned in the 
airworthiness standards for transport category airplanes. These design 
features include a high-speed protection system. 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: Todd Martin, FAA, Airframe and Cabin 
Safety Branch, ANM-115, Transport Airplane Directorate, Aircraft 
Certification Service, 1601 Lind Avenue SW., Renton, Washington, 98057-
3356; telephone 425-227-1178; facsimile 425-227-1149.

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, ailerons and rudder, controlled by the pilot or 
copilot sidestick.
    The Model EMB-550 airplane incorporates a high-speed protection 
system in the airplane's flight control laws. The airplane's high-speed 
protection system limits nose-down pilot authority by adding automatic 
control inputs at threshold speeds above VMO/MMO, 
which influence the results of the traditional recovery maneuvers 
required in Title 14, Code of Federal Regulations (14 CFR) 
25.335(b)(1). This speed protection system was not envisioned when 
Sec.  25.335 was promulgated.

[[Page 31837]]

Type Certification Basis

    Under the provisions of 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: a high-speed protection system that limits 
nose-down pilot authority at speeds above VMO/
MMO. This system prevents the airplane from performing the 
maneuver required under Sec.  25.335(b)(1).

Discussion

    Section 25.335(b)(1) is a dive speed condition that was originally 
adopted in part 4b of the Civil Air Regulations in order to provide an 
acceptable speed margin between design cruise speed and design dive 
speed. Flutter clearance design speeds and airframe design loads are 
impacted by the design dive speed. While the initial condition for the 
upset specified in the rule is 1g level flight, protection is afforded 
for other inadvertent overspeed conditions as well. Section 
25.335(b)(1) is intended as a conservative enveloping condition for 
potential overspeed conditions, including non-symmetric conditions. To 
ensure that potential overspeed conditions are covered, the applicant 
should demonstrate that the dive speed will not be exceeded in 
inadvertent, or gust-induced, upsets resulting in initiation of the 
dive from non-symmetric attitudes; or that the airplane is protected by 
the flight control laws from getting into non-symmetric upset 
conditions. The applicant should conduct a demonstration that includes 
a comprehensive set of conditions, as described in the special 
conditions.
    These special conditions are in lieu of Sec.  25.335(b)(1). Section 
25.335(b)(2), which also addresses the design dive speed, is applied 
separately. Advisory Circular (AC) 25.335-1A, Design Dive Speed, dated 
September 29, 2000, provides an acceptable means of compliance to Sec.  
25.335(b)(2)).
    Special conditions are necessary to address the high-speed 
protection system on the Model EMB-550. The special conditions identify 
various symmetric and non-symmetric maneuvers that will ensure that an 
appropriate design dive speed, VD/MD, is 
established.
    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.
    This special condition is in lieu of 14 CFR 25.335(b)(1). Section 
25.335(b)(2), also addresses the design dive speed, but it is applied 
separately. Advisory Circular (AC) 25.335-1A, Design Dive Speed, dated 
September 29, 2000, provides an acceptable means of compliance to Sec.  
25.335(b)(2).

Discussion of Comments

    Notice of proposed special conditions number 25-12-18-SC for the 
Embraer S.A. Model EMB-550 airplanes was published in the Federal 
Register on January 24, 2013 (78 FR 5146). We received no substantive 
comments, 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

    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. Dive Speed Definition with Speed Protection System.
    (1) In lieu of the requirements of 14 CFR 25.335(b)(1), if the 
flight control system includes functions that act automatically to 
initiate recovery before the end of the 20-second period specified in 
Sec.  25.335(b)(1), VD/MD must be determined from 
the greater of the speeds resulting from the conditions (a) and (b) 
below. The speed increase occurring in these maneuvers may be 
calculated if reliable or conservative aerodynamic data are used.
    (a) From an initial condition of stabilized flight at 
VC/MC, the airplane is upset and takes a new 
flight path 7.5 degrees below the initial path. Control application, up 
to full authority, is made to try and maintain this new flight path. 
Twenty seconds after initiating the upset, manual recovery is made at a 
load factor of 1.5g (0.5 acceleration increment), or such greater load 
factor that is automatically applied by the system with the pilot's 
pitch control neutral. Power, as specified in Sec.  25.175(b)(1)(iv), 
is assumed until recovery is initiated, at which time power reduction 
and pilot-controlled drag devices may be used.
    (b) From a speed below VC/MC, with power to 
maintain stabilized level flight at this speed, the airplane is upset 
so as to accelerate through VC/MC at a flight 
path 15 degrees below the initial path (or at the steepest nose down 
attitude that the system will permit with full control authority if 
less than 15 degrees). The pilot's controls may be in the neutral 
position after reaching VC/MC and before recovery 
is initiated. Recovery may be initiated three seconds after operation 
of the high-speed warning system by application of a load of 1.5g (0.5 
acceleration increment), or such greater load factor that is 
automatically applied by the system with the pilot's pitch control 
neutral. Power may be reduced simultaneously.

[[Page 31838]]

All other means of decelerating the airplane, the use of which is 
authorized up to the highest speed reached in the maneuver, may be 
used. The interval between successive pilot actions must not be less 
than one second.
    (2) The applicant must also demonstrate that the speed margin, 
established as above, will not be exceeded in inadvertent, or gust-
induced, upsets resulting in initiation of the dive from non-symmetric 
attitudes, unless the airplane is protected by the flight control laws 
from getting into non-symmetric upset conditions. The upset maneuvers 
described in paragraphs 32.c(3)(a) and 32.c(3)(c) of AC 25-7C, Flight 
Test Guide for Certification of Transport Category Airplanes, dated 
October 16, 2012, may be used to comply with this requirement.
    (3) Any failure of the high-speed protection system that would 
result in an airspeed exceeding those determined by paragraphs (1) and 
(2) must be less than 10-5 per flight hour.
    (4) Failures of the system must be annunciated to the pilots. 
Flight manual instructions must be provided that reduce the maximum 
operating speeds VMO/MMO. The operating speed 
must be reduced to a value that maintains a speed margin between 
VMO/MMO and VD/MD that is 
consistent with showing compliance with Sec.  25.335(b) without the 
benefit of the high-speed protection system.
    (5) Dispatch of the airplane with the high-speed protection system 
inoperative could be allowed under an approved minimum equipment list 
(MEL) that would require flight manual instructions to indicate reduced 
maximum operating speeds, as described in paragraph (4). In addition, 
the flightdeck display of the reduced operating speeds, as well as the 
overspeed warning for exceeding those speeds, must be equivalent to 
that of the normal airplane with the high-speed protection system 
operative. Also, it must be shown that no additional hazards are 
introduced with the high-speed protection system inoperative.

    Issued in Renton, Washington, on May 21, 2013.
Jeff Duven,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-12535 Filed 5-24-13; 8:45 am]
BILLING CODE 4910-13-P


