[Federal Register Volume 61, Number 65 (Wednesday, April 3, 1996)]
[Proposed Rules]
[Pages 14684-14685]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-8037]



 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 61, No. 65 / Wednesday, April 3, 1996 / 
Proposed Rules  

[[Page 14684]]


DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM-123; Notice No. SC-96-2-NM]


Special Conditions: Embraer (Brazil) Aircraft Corporation Model 
EMB-145 Airplane; High-Intensity Radiated Fields

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed special conditions.

-----------------------------------------------------------------------

SUMMARY: This document proposes special conditions 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 proposed 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: Comments must be received on or before May 20, 1996.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Office of the Assistant Chief Counsel, 
Attn: Rules Docket (ANM-7), Docket No. NM-123, 1601 Lind Avenue SW., 
Renton, Washington, 98055-4056; or delivered in duplicate to the Office 
of the Assistant Chief Counsel at the above address. Comments must be 
marked: Docket No. NM-123. Comments may be inspected in the Rules 
Docket weekdays, except Federal holidays, between 7:30 a.m. and 4:00 
p.m.

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: 

Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting such written data, 
views, or arguments as they may desire. Communications should identify 
the regulatory docket or notice number and be submitted in duplicate to 
the address specified above. All communications received on or before 
the closing date for comments will be considered by the Administrator 
before further rulemaking action is taken on these proposals. The 
proposals contained in this notice may be changed in light of comments 
received. All comments submitted will be available in the Rules Docket 
for examination by interested persons, both before and after the 
closing date for comments. A report summarizing each substantive public 
contact with FAA personnel concerning this rulemaking will be filed in 
the docket. Persons wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must submit with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. NM-123.'' The postcard will 
be date stamped and returned to the commenter.

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, 
except as provided in Sec. 25.2, 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 proposed 
certificate 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. The special conditions 
that may be developed as a result of this notice will form an 
additional part of the type of certification basis. In addition, the 
certification basis may include other special conditions that are not 
relevant to these proposed 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.

[[Page 14685]]


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 the regulations incorporated by reference, special 
conditions are proposed 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 10KHz to 18GHz.
    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 tests 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, the proposed special conditions would be 
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).

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 Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions 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 March 25, 1996.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 96-8037 Filed 4-2-96; 8:45 am]
BILLING CODE 4910-13-M