[Federal Register Volume 78, Number 42 (Monday, March 4, 2013)]
[Rules and Regulations]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2013-04854]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. FAA-2012-1292; Special Conditions No. 25-485-SC]
Special Conditions: Embraer S.A., Model EMB-550 Airplanes;
Electrical/Electronic Equipment Bay Fire Detection and Smoke
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 novel or unusual design
features, specifically distributed electrical and electronic equipment
bays in pressurized areas of the airplane. Older transport category
airplane electrical/electronic equipment bay installations are located
in the lower lobe where the flight crew could determine the origin of
smoke or fire by a straightforward airplane flight manual procedure. In
distributed electrical/electronic bay installations it is not as
straightforward. The FAA has no requirement for smoke and/or fire
detection in the electrical/electronic equipment bays. To ensure
effective mitigation of fires, the FAA proposes these special
conditions. 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 April 3, 2013.
FOR FURTHER INFORMATION CONTACT: Robert C. Jones, FAA, Propulsion and
Mechanical Systems Branch, ANM-112, Transport Airplane Directorate,
Aircraft Certification Service, 1601 Lind Avenue SW., Renton,
Washington 98057-3356; telephone 425-227-1234; 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 airplane has a
conventional configuration with a 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
The Model EMB-550 airplane has electrical/electronic equipment bays
distributed throughout the airplane; three of them are in the
pressurized area. The current airworthiness requirements do not contain
adequate or appropriate safety standards regarding smoke/fire detection
and protection against penetration of hazardous quantities of smoke
from equipment bays into occupied areas of the airplane for this type
of airplane configuration.
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 section 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: Distributed electrical and electronic
equipment bays that were not envisioned at the time this rule was made.
In general, smoke and fire detection systems are designed to:
Automatically shut off power to the affected equipment,
If necessary, reconfigure the environmental control
systems to control any smoke resulting from a fire or overheat
Alert the flight crew to the existence of the fire.
Most airplanes certified under part 25 have one or two electrical
equipment bays located in the lower lobe, adjacent to pressure
regulator/outflow valves or vents. If a fire occurs in an electrical
equipment bay, any smoke is drawn toward the outflow valves or vents
and is discharged from the airplane without entering occupied areas. In
the event of a smoke or fire in one of the electrical equipment bays,
the procedures to isolate the bay on some airplanes requires the flight
crew to use trial and error to determine whether or not the source is
in a particular electrical equipment bay. However, with this approach,
the flight crew does not know where the fire or smoke is because it is
difficult to identify the source, especially during changes of phases
of flight (e.g., climbing or descending) or system transients (e.g.,
changes in the airflow from the environmental control system).
This trial-and-error approach may be acceptable for aircraft with
than two electrical equipment bays, both located in the lower lobe. In
this case, a fire in an electrical equipment bay is in either one bay
or the other. However, for an aircraft with three or more electrical
equipment bays, in the time it takes to determine the source of smoke,
the fire could spread, generating even more smoke and damage.
In the Model EMB-550 airplane, electrical equipment bays are
distributed throughout the airplane in the pressurized compartment.
Section 25.857 requires that cargo compartments have means to prevent
hazardous quantities of smoke or fire extinguishing agent from
penetrating into occupied areas of the airplane. However, the
applicable airworthiness regulations do not address the following:
Preventing hazardous quantities of smoke or extinguishing
agent originating from the electrical equipment bays from penetrating
into occupied areas of the airplane; or
Installing smoke or fire detectors in electrical equipment
The FAA determined that the Model EMB-550 needs a means to detect
smoke or fire in each electrical equipment bay that is located in the
pressurized cabin. This means must indicate in which bay the smoke or
fire occurs, and ensure that the flight crew can depower it. For
situations in which it may be impossible for the flight crew to shut
down all the equipment in the bay due to the use of critical or
essential equipment located in it, Embraer S.A. shall conduct an
Specify the criteria for shutting down specific electrical
equipment in the electrical equipment bay that can be shut down,
Demonstrate that remaining electrical equipment is
protected against fire propagation, such as thermal protection, fire
containment, and other systems as addressed in Advisory Circular 25-16,
Electrical Fault and Fire Prevention and Protection, dated April 5,
The criteria developed for aircraft designs that incorporate
distributed electrical/electronic equipment bays are based upon
existing smoke/fire detection and smoke penetration guidance and
acceptable past practices. Sections 25.831(b), 25.831(c), 25.831(d),
and 25.869(a) provide the general requirements that apply to
electrical/electronic equipment smoke penetration and evacuation.
Flight tests are conducted to demonstrate compliance; however, the
amount of smoke generated and flight test conditions have been highly
The special conditions below require that there must be a means to
detect smoke or fire in each electrical/electronic equipment bay
located in the pressurized compartment. They also include requirements
to prevent propagation of hazardous quantities of smoke or fire
extinguishing agent throughout the passenger cabin.
Discussion of Comments
Notice of proposed special conditions No. 25-12-17-SC for the
Embraer S.A. Model EMB-550 airplanes was published in the Federal
Register on December 19, 2012 (77 FR 75071). 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, the Federal Aviation Administration (FAA) proposes the
following special conditions as part of the type certification basis
for Embraer S.A. Model EMB-550 airplanes.
1. Requirements to prevent propagation of smoke that originates in
electrical equipment bays from entering the passenger cabin and flight
a. To prevent such propagation, means to prevent hazardous
quantities of smoke originating from the electrical equipment bays from
incapacitating passengers and crew must be demonstrated. The
demonstrations must include flight tests, and shall be conducted for
all dispatchable system configurations.
b. A small quantity of smoke may enter an occupied area only under
the following conditions:
i. The smoke enters occupied areas during system transients from
below the deck or main deck sources. No sustained smoke penetration
beyond that from environmental control system transients is permitted,
ii. Penetration of the small quantity of smoke is a dynamic event,
involving either dissipation or mobility. Dissipation is rapid dilution
of the smoke by ventilation air. Mobility is rapid movement of the
smoke into and out of the occupied area. In no case should a light haze
indicative of stagnant airflow form, as this indicates that the
ventilation system is failing to meet the requirements of 14 CFR
iii. The smoke from a source below the main deck must not rise
above armrest height on the main deck, and
iv. The smoke from a source in the main deck must dissipate rapidly
via dilution with fresh air and be evacuated from the airplane. The
Airplane Flight Manual (AFM) must include procedures to evacuate smoke
from the occupied areas. To demonstrate that the quantity of smoke is
small, a flight test must be conducted which simulates the emergency
procedures used in the event of a fire during flight, including the use
of VMO/MMO descent profiles and a simulated
landing, if such conditions are specified in the emergency procedure.
2. Requirement for smoke or fire detection in electrical/electronic
equipment bays: A smoke or fire detection system compliant with
Sec. Sec. 25.855(a), (b), (c), and (d); and Sec. 25.858 must be
provided for each electrical/electronic equipment bay in the
pressurized cabin. Each system must provide a visual indication to the
flight deck within one minute after the start of a fire. Airplane
flight tests must be conducted to show compliance with these
requirements, and the performance of the detectors must be shown in
accordance with Advisory Circular 25-9A, Smoke Detection, Penetration,
and Evacuation Tests and Related Flight Manual Emergency Procedures, or
other means acceptable to the FAA.
3. Requirement for AFM procedures safety analysis: It shall be
demonstrated that the AFM procedures to shut down electrical/electronic
equipment bays, or part of them, in case of smoke/fire detection, do
not compromise the safe operation of the aircraft. If a procedure
requests to shut down only part of the equipment, the remaining
equipment shall be incorporated with safety precautions against fire
Issued in Renton, Washington, on February 26, 2013.
Manager, Transport Airplane Directorate, Aircraft Certification
[FR Doc. 2013-04854 Filed 3-1-13; 8:45 am]
BILLING CODE 4910-13-P