[Federal Register Volume 61, Number 146 (Monday, July 29, 1996)]
[Rules and Regulations]
[Pages 39305-39306]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-19107]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-123; Special Conditions No. 25-ANM-118]
Special Conditions: Embraer (Brazil) Aircraft Corporation Model
EMB-145 Airplane; High-Intensity Radiated Fields
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the Embraer Model EMB-
145 airplane. This new airplane will utilize new avionics/electronic
systems that provide critical data to the flightcrew. The applicable
regulations do not contain adequate or appropriate safety standards for
the protection of these systems from the effects of high-intensity
radiated fields. 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.
EFFECTIVE DATE: August 28, 1996.
FOR FURTHER INFORMATION CONTACT:
Gerry Lakin, FAA, Standardization Branch, ANM-113, Transport Airplane
Directorate, Aircraft Certification Service, 1601 Lind Avenue, SW.,
Renton, Washington, 98055-4056; telephone (206) 227-1187; facsimile
(206) 227-1149.
SUPPLEMENTARY INFORMATION:
Background
On August 30, 1989, Embraer Aircraft Corporation, Caixa Postal 343,
12227-901 Sao Jose dos Campos, Sao Paulo SP Brasil, applied for a new
type certificate in the transport airplane category for the Model EMB-
145 airplane. The EMB-145 is a T-tail, low swept wing, small transport
airplane powered by two Allison GMA-3007A turbofan engines mounted on
pylons extending from the aft fuselage. Each engine will be capable of
delivering 7,040 pounds thrust. The flight controls will be powered and
capable of manual reversion. The airplane has a seating capacity of up
to 50 passengers, and a maximum takeoff weight of 42,328 pounds.
Type Certification Basis
Under the provisions of Sec. 21.17 of the FAR, Embraer must show
that the Model EMB-145 meets the applicable provisions of part 25,
effective February 1, 1965, as amended by Amendments 25-1 through 25-
75. In addition, the certification basis for the Model EMB-145 includes
part 34, effective September 10, 1990, plus any amendments in effect at
the time of certification; and part 36, effective December 1, 1969, as
amended by Amendment 36-1 through the amendment in effect at the time
of certification. No exemptions are anticipated. These special
conditions form an additional part of the type certification basis. In
addition, the certification basis may include other special conditions
that are not relevant to these special conditions.
If the Administrator finds that the applicable airworthiness
regulations (i.e., part 25, as amended) do not contain adequate or
appropriate safety standards for the Embraer Model EMB-145 because of a
novel or unusual design feature, special conditions are prescribed
under the provisions of Sec. 21.16 to establish a level of safety
equivalent to that established in the regulations.
Special conditions, as appropriate, are issued in accordance with
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28
and 11.29, and become part of the type certification basis in
accordance with Sec. 21.17(a)(2).
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 novel or
unusual design feature, the special conditions would also apply to the
other model under the provisions of Sec. 21.101(a)(1).
Novel or Unusual Design Features
The Model EMB-145 incorporates new avionic/electronic
installations, including a digital Electronic Flight Instrument System
(EFIS), Air Data System, Attitude and Heading Reference System (AHRS),
Navigation and Communication System, Autopilot System, and a Full
Authority Digital Engine Control (FADEC) system that controls critical
engine parameters. These systems may be vulnerable to high-intensity
radiated fields (HIRF) external to the airplane.
Discussion
There is no specific regulation that addresses protection
requirements for electrical and electronic systems from HIRF. Increased
power levels from ground-based radio transmitters and the growing use
of sensitive electrical and electronic systems to command and control
airplanes have made it necessary to provide adequate protection.
To ensure that a level of safety is achieved equivalent to that
intended by
[[Page 39306]]
the regulations incorporated by reference, special conditions are
issued for the Embraer Model EMB-145, which would require that new
technology electrical and electronic systems, such as the EFIS, FADEC,
AHRS, etc., be designed and installed to preclude component damage and
interruption of function due to both the direct and indirect effects of
HIRF.
With the trend toward increased power levels from ground-based
transmitters, plus the advent of space and satellite communications,
coupled with electronic command and control of the airplane, the
immunity of critical digital avionics systems to HIRF must be
established.
It is not possible to precisely define the HIRF to which the
airplane will be exposed in service. There is also uncertainty
concerning the effectiveness of airframe shielding for HIRF.
Furthermore, coupling of electromagnetic energy to cockpit-installed
equipment through the cockpit window apertures is undefined. Based on
surveys and analysis of existing HIRF emitters, an adequate level of
protection exists when compliance with the HIRF protection special
condition is shown with either paragraphs 1 or 2 below.
1. A minimum threat of 100 volts per meter peak electric field
strength from 10 KHz to 18 GHz.
a. The threat must be applied to the system elements and their
associated wiring harnesses without the benefit of airframe shielding.
b. Demonstration of this level of protection is established through
system test and analysis.
2. A threat external to the airframe of the following field
strengths for the frequency ranges indicated.
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Peak (V/ Average
Frequency M) (V/M)
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10 KHz-100 KHz........................................ 50 50
100 KHz-500 KHz....................................... 60 60
500 KHz-2000 KHz...................................... 70 70
2 MHz-30 MHz.......................................... 200 200
30 MHz-100 MHz........................................ 30 30
100 MHz-200 MHz....................................... 150 33
200 MHz-400 MHz....................................... 70 70
400 MHz-700 MHz....................................... 4,020 935
700 MHz-1000 MHz...................................... 1,700 170
1 GHz-2 GHz........................................... 5,000 990
2 GHz-4 GHz........................................... 6,680 840
4 GHz-6 GHz........................................... 6,850 310
6 GHz-8 GHz........................................... 3,600 670
8 GHz-12 GHz.......................................... 3,500 1,270
12 GHz-18 GHz......................................... 3,500 360
18 GHz-40 GHz......................................... 2,100 750
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As discussed above, these special conditions are applicable
initially to the Embraer Model EMB-145. Should Embraer 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 under the provisions of
Sec. 21.101(a)(1).
Discussion of Comments
Notice of proposed special conditions No. SC-96-2-NM was published
in the Federal Register on April 3, 1996 (61 FR 14684). One commenter
responded to the request for comments and concurs with the special
conditions as proposed.
Conclusion
This action affects only certain design features on the Embraer
Model EMB-145 airplane. It is not a rule of general applicability and
affects only the manufacturer who applied to the FAA for approval of
these features on the airplane.
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 the Embraer Model EMB-145 series
airplanes.
1. Protection from Unwanted Effects of High-Intensity Radiated
Fields (HIRF). Each electrical and electronic system that performs
critical functions must be designed and installed to ensure that the
operation and operational capability of these systems to perform
critical functions are not adversely affected when the airplane is
exposed to high-intensity radiated fields.
2. For the purpose of these special conditions, the following
definition applies: Critical Functions. Functions whose failure would
contribute to or cause a failure condition that would prevent the
continued safe flight and landing of the airplane.
Issued in Renton, Washington, on July 12, 1996.
Stewart R. Miller,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 96-19107 Filed 7-26-96; 8:45 am]
BILLING CODE 4910-13-M
