Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight Envelope Protection: Performance Credit for Automatic Takeoff Thrust Control System (ATTCS) During Go-Around, 6195-6198 [2013-01928]

Agencies

• Federal Aviation Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 78, Number 20 (Wednesday, January 30, 2013)]
[Rules and Regulations]
[Pages 6195-6198]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-01928]



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Federal Register / Vol. 78, No. 20 / Wednesday, January 30, 2013 / 
Rules and Regulations

[[Page 6195]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. FAA-2012-1199; Special Conditions No. 25-476-SC]


Special Conditions: Embraer S.A., Model EMB-550 Airplanes; Flight 
Envelope Protection: Performance Credit for Automatic Takeoff Thrust 
Control System (ATTCS) During Go-Around

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 associated with the use of an Automatic Takeoff Thrust Control 
System (ATTCS) during go-around. 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: March 1, 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 425-227-2011; 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.
    Embraer S.A. has incorporated an ATTCS function into the engine of 
the Model EMB-550 airplane. It has a full authority digital electronic 
control system architecture. Embraer S.A. proposed allowing performance 
credit for this function during go-arounds to show compliance with the 
requirements of Sec.  25.121(d) for approach climb performance. Since 
the airworthiness requirements do not contain appropriate safety 
standards for approach climb performance using ATTCS, special 
conditions are required to establish a level of safety equivalent to 
that of the regulations.
    Part 25 appendix I contains standards for use of ATTCS during 
takeoff. These special conditions establish standards to extend the use 
of ATTCS to the go-around phase.

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 Embraer S.A. Model EMB-550 airplane has an ATTCS that is used 
for both takeoff and go-around functions.
    Section 25.904 and part 25 appendix I refer to operations of ATTCS 
only during takeoff. The Embraer S.A. Model EMB-550 airplane also 
provides for use of ATTCS for go-arounds. As a result, if an engine 
failure occurs during a go-around, the remaining engine automatically 
applies maximum go-around thrust. In addition, in the case of an 
approach with one engine already inoperative, if it is necessary to 
perform a go-around, the operating engine automatically applies maximum 
go-around thrust.
    These special conditions are intended to ensure that the ATTCS 
functions correctly and meets expected performance requirements during 
go-arounds when the airplane is limited by weight, altitude, and/or 
temperature during an approach.

Discussion

    Since current airworthiness requirements do not contain safety 
standards to allow credit for ATTCS in determining approach climb 
performance, these special conditions are required to establish a level 
of safety equivalent to that of the regulations. The definition of a 
critical time interval for the approach climb case similar to the 
critical time interval for takeoff defined in part 25 appendix I is of 
primary importance. During an approach climb, it must be extremely 
improbable to violate a flight path based on the climb gradient 
requirement of Sec.  25.121(d).

[[Page 6196]]

This climb gradient requirement implies a minimum one-engine-
inoperative flight path capability with the airplane in the approach 
configuration. The engine may have been inoperative before initiating 
the go-around, or it may become inoperative during the go-around. The 
definition of the critical time interval must consider both 
possibilities.
    The propulsive thrust used to determine compliance with the 
approach climb requirements of Sec.  25.121(d) is limited to the lesser 
of:
     The thrust provided by the ATTCS, or
     111% of the thrust resulting from the initial thrust 
setting with the ATTCS failing to perform its uptrim function and 
without action by the flightcrew to reset thrust.

This requirement serves to limit the adverse performance effects of a 
combined engine and ATTCS failure, and ensures adequate performance of 
an all-engines-operating go-around.

Discussion of Comments

    Notice of proposed special conditions No. 25-12-06-SC for the 
Embraer S.A. Model EMB-550 airplanes was published in the Federal 
Register on November 9, 2012, (77 FR 67309). No substantitve comments 
were received, and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Embraer S.A. 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. The Model EMB-550 airplane must comply with the requirements of 
14 CFR 25.904 and appendix I to 14 CFR part 25 and the following 
requirements pertaining to the go-around phase of flight:
    2. Definitions
    a. Takeoff/go-around (TOGA): Throttle lever in takeoff or go-around 
position.
    b. Automatic takeoff thrust control system (ATTCS): The ATTCS in 
Model EMB-550 airplanes is defined as the entire automatic system 
available during takeoff and in go-around mode, including all devices, 
both mechanical and electrical, that sense engine failure, transmit 
signals, actuate fuel controls or power levers (or increase engine 
power by other means on operating engines to achieve scheduled thrust 
or power increase), and furnish cockpit information on system 
operation.
    c. Critical time interval: The definition of the critical time 
interval in 14 CFR appendix I 25.2(b) must be expanded to include the 
following:
    (1) When conducting an approach for landing using ATTCS, the 
critical time interval is defined as follows:
    (i) The critical time interval begins at a point on a 2.5 degree 
approach glide path from which, assuming a simultaneous engine and 
ATTCS failure, the resulting approach climb flight path intersects a 
flight path originating at a later point on the same approach path 
corresponding that corresponds to the 14 CFR part 25 one-engine-
inoperative approach climb gradient. The period of time from the point 
of simultaneous engine and ATTCS failure to the intersection of these 
flight paths must be no shorter than the time interval used in 
evaluating the critical time interval for takeoff beginning from the 
point of simultaneous engine and ATTCS failure and ending upon reaching 
a height of 400 feet.
    (ii) The critical time interval ends at the point on a minimum 
performance, all-engines-operating go-around flight path from which, 
assuming a simultaneous engine and ATTCS failure, the resulting minimum 
approach climb flight path intersects a flight path corresponding to 
the 14 CFR part 25 minimum one-engine-inoperative approach climb 
gradient. The all-engines-operating go-around flight path and the 14 
CFR part 25 one-engine-inoperative approach climb gradient flight path 
originate from a common point on a 2.5 degree approach path. The period 
of time from the point of simultaneous engine and ATTCS failure to the 
intersection of these flight paths must be no shorter than the time 
interval used in evaluating the critical time interval for the takeoff 
beginning from the point of simultaneous engine and ATTCS failure and 
ending upon reaching a height of 400 feet.
    (2) The critical time interval must be determined at the altitude 
resulting in the longest critical time interval for which one-engine-
inoperative approach climb performance data are presented in the 
airplane flight manual (AFM).
    (3) The critical time interval is illustrated in the following 
figure:

[[Page 6197]]

[GRAPHIC] [TIFF OMITTED] TR30JA13.013

    3. Performance and system reliability requirements: The applicant 
must comply with the performance and ATTCS reliability requirements as 
follows:
    a. An ATTCS failure or a combination of failures in the ATTCS 
during the critical time interval:
    (1) Must not prevent the insertion of the maximum approved go-
around thrust or power, or must be shown to be a remote event.
    (2) Must not result in a significant loss or reduction in thrust or 
power, or must be shown to be an extremely improbable event.
    b. The concurrent existence of an ATTCS failure and an engine 
failure during the critical time interval must be shown to be extremely 
improbable.
    c. All applicable performance requirements of 14 CFR part 25 must 
be met with an engine failure occurring at the most critical point 
during go-around with the ATTCS functioning.
    d. The probability analysis must include consideration of ATTCS 
failure occurring after the time at which the flightcrew last verifies 
that the ATTCS is in a condition to operate until the beginning of the 
critical time interval.
    e. The propulsive thrust obtained from the operating engine after 
failure of the critical engine during a go-around used to show 
compliance with the one-engine-inoperative climb requirements of Sec.  
25.121(d) may not be greater than the lesser of:
    (1) The actual propulsive thrust resulting from the initial setting 
of power or thrust controls with the ATTCS functioning; or
    (2) 111% of the propulsive thrust resulting from the initial 
setting of power or thrust controls with the ATTCS failing to reset 
thrust or power and without any action by the flightcrew to reset 
thrust or power.
    4. Thrust setting
    a. The initial go-around thrust setting on each engine at the 
beginning of the go-around phase may not be less than any of the 
following:
    (1) That required to permit normal operation of all safety-related 
systems and equipment dependent upon engine thrust or power lever 
position; or
    (2) That shown to be free of hazardous engine response 
characteristics and not to result in any unsafe aircraft operating or 
handling characteristics when thrust or power is advanced from the 
initial go-around position to the maximum approved power setting.
    b. For approval to use an ATTCS for go-arounds, the thrust setting 
procedure must be the same for go-arounds initiated with all engines 
operating as for go-around initiated with one engine inoperative.
    5. Powerplant controls
    a. In addition to the requirements of Sec.  25.1141, no single 
failure or malfunction, or probable combination thereof, of the ATTCS, 
including associated systems, may cause the failure of any powerplant 
function necessary for safety.
    b. The ATTCS must be designed to:
    (1) Apply thrust or power on the operating engine(s), following any 
one-engine failure during a go-around, to achieve the maximum approved 
go-around thrust without exceeding the engine operating limits;
    (2) Permit manual decrease or increase in thrust or power up to the 
maximum go-around thrust approved for the airplane under the existing 
conditions through the use of the power lever. For airplanes equipped 
with limiters that automatically prevent the engine operating limits 
from being exceeded under existing ambient conditions, other means may 
be used to increase the thrust in the event of an ATTCS failure, 
provided that the means:
    (i) Is located on or forward of the power levers;
    (ii) Is easily identified and operated under all operating 
conditions by a single action of either pilot with the hand that is 
normally used to actuate the power levers; and
    (iii) Meets the requirements of Sec.  25.777(a), (b), and (c).
    (3) Provide a means to verify to the flightcrew before beginning an 
approach for landing that the ATTCS is in a condition to operate 
(unless it can be demonstrated that an ATTCS failure combined with an 
engine failure during an entire flight is extremely improbable); and
    (4) Provide a means for the flightcrew to deactivate the automatic 
function. This means must be designed to prevent inadvertent 
deactivation.
    6. Powerplant instruments: In addition to the requirements of Sec.  
25.1305:
    a. A means must be provided to indicate when the ATTCS is in the 
armed or ready condition; and
    b. If the inherent flight characteristics of the airplane do not 
provide adequate warning that an engine has failed, a warning system 
that is independent of the ATTCS must be provided to give the pilot a 
clear warning of any engine failure during a go-around.


[[Page 6198]]


    Issued in Renton, Washington, on January 24, 2013.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2013-01928 Filed 1-29-13; 8:45 am]
BILLING CODE 4910-13-P