[Federal Register Volume 67, Number 185 (Tuesday, September 24, 2002)]
[Rules and Regulations]
[Pages 59773-59775]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-24242]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM228, Special Conditions No. 25-213-SC]


Special Conditions: Raytheon Aircraft Company Model HS.125 Series 
700A Airplanes; High Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for Raytheon Aircraft 
Company Model HS.125 Series 700A airplanes modified by Duncan Aviation. 
These airplanes will have novel and unusual design features when 
compared to the state of technology envisioned in the airworthiness 
standards for transport category airplanes. The modifications, under 
three separate supplemental type certificate (STC) projects, 
incorporate the installation of a Collins FDS2000 Electronic Flight 
Instrument System (EFIS), a dual Collins AHS-3000A Attitude Heading 
Reference System (AHARS), and a dual IS&S Air Data System. The 
applicable airworthiness 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.

DATES: The effective date of these special conditions is September 17, 
2002. Comments must be received on or before October 24, 2002.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attn: Rules Docket (ANM-113), Docket No. NM228, 1601 Lind 
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. All 
comments must be marked: Docket No. NM228. 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: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay certification of the 
airplane and thus delivery of the affected aircraft. In addition, the 
substance of these special conditions has been subject to the public 
comment process in several prior instances with no substantive comments 
received. The FAA therefore finds that good cause exists for making 
these special conditions effective upon issuance; however, the FAA 
invites interested persons to participate in this rulemaking by 
submitting written comments, data, or views. The most helpful comments 
reference a specific

[[Page 59774]]

portion of the special conditions, explain the reason for any 
recommended change, and include supporting data. We ask that you send 
us two copies of written comments.
    We will file in the docket all comments we receive, as well as a 
report summarizing each substantive public contact with FAA personnel 
concerning these special conditions. The docket is available for public 
inspection before and after the comment closing date. If you wish to 
review the docket in person, go to the address in the ADDRESSES section 
of this preamble between 7:30 a.m. and 4 p.m., Monday through Friday, 
except Federal holidays.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions in light of the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on this 
proposal, include with your comments a pre-addressed, stamped postcard 
on which the docket number appears. We will stamp the date on the 
postcard and mail it back to you.

Background

    On May 14, 2002, Duncan Aviation, Inc., P.O. Box 81887, Lincoln, 
Nebraska 68501, applied for three supplemental type certificates (STCs) 
to modify Raytheon Aircraft Company Model HS.125 Series 700A airplanes 
approved under Type Certificate No. A3EU. The HS.125 Series 700A 
airplanes are executive type transports that have two aft mounted 
turbine engines, a maximum passenger load of 15 passengers, and a 
maximum operating speed of 280 to 320 KTS depending on the fuel loading 
configuration. The modifications, under three separate supplemental 
type certificate (STC) projects, incorporate the installation of a 
Collins FDS2000 Electronic Flight Instrument System (EFIS), a dual 
Collins AHS-3000A Attitude Heading Reference System (AHARS), and a dual 
Innovative Solutions & Support, Inc. (IS&S) Air Data System.
    The Collins FDS2000 (EFIS) Flight Display System provides the 
aircraft interface, data processing, display processing and display 
control to replace four existing electro-mechanical Attitude Direction/
Horizontal Situation indicators (ADI/HSI). In doing this, this 
equipment provides critical functions, display of aircraft pitch and 
roll, and essential functions (display of heading and navigation). The 
dual Collins AHS-3000A Attitude Heading Reference System (AHARS) is a 
solid state strap-down attitude/heading reference system which provides 
measurements of the aircraft pitch, roll, and heading Euler angles for 
use by cockpit displays, flight control and management systems, and 
other avionics equipment. The dual IS&S Air Data System replaces the 
existing pilot and copilot pneumatic altimeters with IS&S Air Data/
Altimeter units. These advanced systems use electronics to a far 
greater extent than the original flight and navigation systems and may 
be more susceptible to electrical and magnetic interference caused by 
high-intensity radiated fields (HIRF). This disruption of signals could 
result in loss of either attitude, altimeter, heading, or present 
misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Duncan Aviation, Inc. must 
show that the Raytheon Aircraft Company Model HS.125 Series 700A 
airplanes, as changed, continue to meet the applicable provisions of 
the regulations incorporated by reference in Type Certificate No. A3EU, 
or the applicable regulations in effect on the date of application for 
the change. The regulations incorporated by reference in the type 
certificate are commonly referred to as the ``original type 
certification basis.'' The certification basis for the modified 
Raytheon Aircraft Company Model HS.125 Series 700A airplanes includes 
CAR. 10, British Civil Airworthiness Requirements (1st November 1963), 
and Special Conditions notified by the United States Government to 
Government of the United Kingdom including Validation Arrangements 
(V.A.) Note 1, Issue 1 dated April 19, 1961. This certification is 
equivalent to CAR.4b dated December 1953, Amendment 4b-1 through 4b-11, 
exclusive of CAR 4b.350 (e) and includes Special Regulation SR.422B. 
Other applicable amendments, Federal Aviation Regulations, and special 
conditions are noted in Type Certificate Data Sheet (TCDS) A3EU.
    If the Administrator finds that the applicable airworthiness 
regulations (that is, CAR 4b or 14 CFR part 25, as amended) do not 
contain adequate or appropriate safety standards for the Raytheon 
Aircraft Company Model HS.125 Series 700A airplanes 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 Raytheon Aircraft Company Model HS.125 Series 700A 
airplanes must comply with the fuel vent and exhaust emission 
requirement of 14 CFR part 34 and the noise certification requirement 
of part 36.
    Special conditions, as defined in 14 CFR 11.19, are issued in 
accordance with Sec.  11.38, and become part of the type certification 
basis in accordance with Sec.  21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should Duncan Aviation, Inc. apply at a later date for 
a supplemental type certificate to modify any other model already 
included on the same type certificate to incorporate the same novel or 
unusual design features, these special conditions would also apply to 
the other model under the provisions of 14 CFR 21.101(a)(1).

Novel or Unusual Design Features

    The Raytheon Aircraft Company Model HS.125 Series 700A airplanes 
will incorporate, under three separate supplemental type certificate 
(STC) projects, the installation of a Collins FDS-2000 Electronic 
Flight Instrument System (EFIS), a dual Collins AHS-3000A Attitude 
Heading Reference System (AHARS), and a dual IS&S Air Data System. 
Because these advanced systems use electronics to a far greater extent 
than the original flight and navigation systems, they may be more 
susceptible to electrical and magnetic interference caused by high-
intensity radiated fields (HIRF) external to the airplane. The current 
airworthiness standards (14 CFR part 25) do not contain adequate or 
appropriate safety standards that address protecting this equipment 
from the adverse effects of HIRF. Accordingly, these instruments are 
considered to be a novel or unusual design feature.

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 HS.125 
Series 700A airplanes modified to include the new flight and navigation 
systems. These special conditions will require that the new Collins 
FDS-2000 Flight Display System, the Dual Collins AHS-3000A Attitude/
Heading Reference System and the Dual IS&S Air Data Systems, which

[[Page 59775]]

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, the 
immunity of critical digital 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 in accordance with either paragraph 1 OR 2 below:
    1. A minimum threat of 100 volts rms (root-mean-square) 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 of the field strengths 
indicated in the table below for the frequency ranges indicated. Both 
peak and average field strength components from the table below 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.

Applicability

    As discussed above, these special conditions are applicable to 
Raytheon Aircraft Company Model HS.125 Series 700A airplanes modified 
by Duncan Aviation, Inc. to include the Collins FDS-2000 Flight Display 
System, the Dual Collins AHS-3000A Attitude/Heading Reference System 
and the Dual IS&S Air Data System. Should Duncan Aviation, Inc. apply 
at a later date for a supplemental type certificate to modify any other 
model already included on Type Certificate A3EU to incorporate the same 
novel or unusual design features, these special conditions would apply 
to that model as well under the provisions of 14 CFR 21.101(a)(1).

Conclusion

    This action affects only certain design features on Raytheon 
Aircraft Company Model HS.125 Series 700A airplanes modified by Duncan 
Aviation, Inc. 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.
    The substance of the special conditions for this airplane has been 
subjected to notice and comment procedure in several prior instances 
and has been derived without substantive change from those previously 
issued. Because a delay would significantly affect the certification of 
the airplane, which is imminent, the FAA has determined that prior 
public notice and comment are unnecessary and impracticable, and good 
cause exists for adopting these special conditions upon issuance. The 
FAA is requesting comments to allow interested persons to submit views 
that may not have been submitted in response to the prior opportunities 
for comment described above.

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 supplemental type certification basis for Raytheon Aircraft Company 
Model HS.125 Series 700A airplanes modified by Duncan Aviation, Inc.
    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 September 17, 2002.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-24242 Filed 9-23-02; 8:45 am]
BILLING CODE 4910-13-P