[Federal Register Volume 65, Number 50 (Tuesday, March 14, 2000)]
[Proposed Rules]
[Pages 13703-13704]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-6127]



[[Page 13703]]

=======================================================================
-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM170; Notice No. 25-00-01-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.

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

SUMMARY: This notice proposes special conditions 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 proposed 
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.

DATES: Comments must be received on or before April 13, 2000.

ADDRESSES: Comments on these proposed special conditions may be mailed 
in duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-114), Docket No. NM170, 1601 Lind 
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. Comments 
must be marked: Docket No. NM170. 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: 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:

Comments Invited

    Interested persons are invited to participate in the making of 
these 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. The 
proposals contained in this notice may be changed in light of the 
comments received. All comments received 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. Commenters wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. NM170.'' The postcard will be date stamped and 
returned to the commenter.

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 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 14 CFR 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model 4000 must comply with the part 25 fuel vent and 
exhaust emission requirements of 14 CFR part 34 and the part 25 noise 
certification requirements of 14 CFR 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, 
which 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

[[Page 13704]]

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:
    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.

------------------------------------------------------------------------
                                                         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 computer 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.

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 feature, 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.

PART 25--[AMENDED]

    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 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 March 6, 2000.
Vi L. Lipski
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service, ANM-100.
[FR Doc. 00-6127 Filed 3-10-00; 8:45 am]
BILLING CODE 4910-13-P