[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.

------------------------------------------------------------------------
                                                        Peak (V/ Average
                       Frequency                           M)     (V/M) 
------------------------------------------------------------------------
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
------------------------------------------------------------------------

    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