[Federal Register Volume 65, Number 109 (Tuesday, June 6, 2000)]
[Rules and Regulations]
[Pages 35813-35814]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-14156]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM170; Special Conditions No. 25-162-SC]


Special Conditions: Raytheon Aircraft Company Model 4000; High 
Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Raytheon Aircraft 
Company Model 4000 airplane. This airplane will utilize new avionics/
electronics and electrical systems that will perform critical 
functions. 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 (HIRF). These special 
conditions contain the additional safety standards that the 
Administrator considers necessary to establish a level of safety 
equivalent to that provided by the existing airworthiness standards.

EFFECTIVE DATE: July 6, 2000.

FOR FURTHER INFORMATION CONTACT: Mark Quam, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-2145; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Background

    On May 3, 1996, Raytheon Aircraft Company, PO Box 85, Wichita, 
Kansas 67201-0085, submitted an application for a new type certificate 
for the Raytheon Model 4000. The significant aircraft design features 
include an 84 inch diameter graphite composite fuselage, new metal wing 
and a graphite composite skin on aluminum sub-structure empennage. The 
Model 4000 is 69 feet, 2 inches in length and 61 feet, 9 inches in 
width. It has a Primus Epic flightdeck, and two aft mounted PW308A 
engines. There are 12 forward-facing seats and a forward observer seat. 
The significant systems features include a new state of the art 
integrated avionics/electronics and electrical systems suite. The 
avionics/electronics and electrical systems installed in this airplane 
have the potential to be vulnerable to high-intensity radiated fields 
(HIRF) external to the airplane.

Type Certification Basis

    Under the provisions of 14 CFR Sec. 21.17, Raytheon Aircraft 
Company must show that the Model 4000 meets the applicable provisions 
of part 25, as amended by Amendment 25-1 through Amendment 25-87 
thereto.
    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 Raytheon Aircraft Company Model 
4000 airplane because of novel or unusual design features, special 
conditions are prescribed under the provisions of Sec. 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model 4000 must comply with the fuel vent and exhaust 
emission requirements of part 34 and the noise certification 
requirements of part 36, and the FAA must issue a finding of regulatory 
adequacy pursuant to Sec. 611 of Public Law 92-574, the ``Noise Control 
Act of 1972.''
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49, after public notice, as required by Secs. 11.28 and 
11.29(b), 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 Raytheon Aircraft Company Model 4000 airplanes will utilize new 
avionics/electronics and electrical systems that will perform critical 
functions. These systems may be vulnerable to HIRF external to the 
airplane. The significant systems features include a new state of the 
art integrated avionics/electronics and electrical systems suite. The 
avionics/electronics and electrical systems installed in this aircraft 
have the potential to 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 avionics/electronics and electrical 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 needed for the Raytheon Aircraft Company Model 4000. 
These special conditions require that new avionics/electronics and 
electrical systems that perform critical functions be designed and 
installed to preclude component damage and interruption of function due 
to both the direct and indirect effects of HIRF.

High-Intensity Radiated Fields (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, and the 
use of composite material in the airplane structure, the immunity of 
critical avionics/electronics and electrical 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 paragraph 1, or 2 below:

[[Page 35814]]

    1. A minimum threat of 100 volts rms per meter 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 tests and analysis.
    2. A threat external to the airframe for both of the following 
field strengths for the frequency ranges indicated. Both peak and 
average field strength components from the Table are to be 
demonstrated.

------------------------------------------------------------------------
                                                         Field strength
                                                       (volts per meter)
                      Frequency                       ------------------
                                                        Peak    Average
------------------------------------------------------------------------
10 kHz-100 kHz.......................................      50         50
100 kHz-500 kHz......................................      50         50
500 kHz-2 MHz........................................      50         50
2 MHz-30 MHz.........................................     100        100
30 MHz-70 MHz........................................      50         50
70 MHz-100 MHz.......................................      50         50
100 MHz-200 MHz......................................     100        100
200 MHz-400 MHz......................................     100        100
400 MHz-700 MHz......................................     700         50
700 MHz-1 GHz........................................     700        100
1 GHz-2 GHz..........................................    2000        200
2 GHz-4 GHz..........................................    3000        200
4 GHz-6 GHz..........................................    3000        200
6 GHz-8 GHz..........................................    1000        200
8 GHz-12 GHz.........................................    3000        300
12 GHz-18 GHz........................................    2000        200
18 GHz-40 GHz........................................     600       200
------------------------------------------------------------------------
The field strengths are expressed in terms of peak of the root-mean-
  square (rms) over the complete modulation period.

    The threat levels identified above are the result of an FAA review 
of existing studies on the subject of HIRF, in light of the ongoing 
work of the Electromagnetic Effects Harmonization Working Group of the 
Aviation Rulemaking Advisory Committee.

Discussion of Comments

    Notice of proposed special conditions No. 25-00-01-SC for the 
Raytheon Aircraft Model 4000 airplanes was published in the Federal 
Register on March 14, 2000 (65 FR 13703). No comments were received, 
and the special conditions are adopted as proposed.

Applicability

    As discussed above, these special conditions are applicable to the 
Model 4000 airplane. Should Raytheon Aircraft Company apply at a later 
date for a change to the type certificate to include another model 
incorporating the same novel or unusual design features, these 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 Raytheon 
Aircraft Company Model 4000 airplanes. It is not a rule of general 
applicability and affects only the applicant 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 Raytheon Aircraft Company Model 4000 
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 this special condition, 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 May 22, 2000.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 00-14156 Filed 6-5-00; 8:45 am]
BILLING CODE 4910-13-U