[Federal Register Volume 68, Number 2 (Friday, January 3, 2003)]
[Rules and Regulations]
[Pages 255-257]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-63]



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  Federal Register / Vol. 68, No. 2 / Friday, January 3, 2003 / Rules 
and Regulations  

[[Page 255]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM242, Special Conditions No. 25-225-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.

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

SUMMARY: These special conditions are issued for Raytheon Aircraft 
Company Model HS.125 Series 700A airplanes modified by Elliott Aviation 
Technical Products Development, Inc. These modified airplanes will have 
a novel and unusual design feature when compared to the state of 
technology envisioned in the airworthiness standards for transport 
category airplanes. The modification incorporates the installation of 
an Electronic Flight Instrument System (EFIS) for display of critical 
flight parameters (altitude, airspeed, and attitude) to the crew. 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 December 23, 
2002. Comments must be received on or before February 3, 2003.

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. NM242, 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. NM242.

FOR FURTHER INFORMATION CONTACT: Meghan Gordon, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification 
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056; 
telephone (425) 227-2138; facsimile (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for prior public 
comment is 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 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 based on the comments we receive.
    If you want the FAA to acknowledge receipt of your comments on 
these special conditions, 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 July 25, 2002, Elliott Aviation Technical Products Development, 
Inc., Quad City Airport, Moline, Illinois 61266-0100, applied for a 
supplemental type certificate (STC) 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 modification 
incorporates the installation of the Rockwell Collins FDS 2000 
Electronic Flight Instrument System (EFIS). This system uses flat 
information display panels for display of critical flight parameters 
(heading and attitude) to the crew. These displays can be susceptible 
to disruption to both command and response signals as a result of 
electrical and magnetic interference caused by high-intensity radiated 
fields (HIRF) external to the airplane. This disruption of signals 
could result in the loss of all critical flight information displays 
and annunciations or present misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Elliott Aviation Technical 
Products Development, 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 include 14 CFR part 25 effective February 1, 1965, as 
amended

[[Page 256]]

by Amendments 25-2 and 25-20, as described in Type Certificate Data 
Sheet A3EU.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., 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 Sec.  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), Amendment 21-69, effective 
September 16, 1991.
    Special conditions are initially applicable to the model for which 
they are issued. Should Elliott Aviation Technical Products 
Development, Inc., apply at a later date for a supplemental type 
certificate to modify any other model included Type Certificate No. 
A3EU to incorporate 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), Amendment 21-69, effective September 
16, 1991.

Novel or Unusual Design Features

    As noted earlier, the modified Raytheon Aircraft Company Model 
HS.125 Series 700A airplanes will incorporate the Rockwell Collins FDS 
2000 Electronic Flight Instrument System (EFIS). 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 of part 25 do not contain adequate or appropriate safety 
standards for the protection of this equipment from the adverse effects 
of HIRF. Accordingly, this system is 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 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 needed for the Raytheon Aircraft Company Model HS.125 
Series 700A airplanes modified by Elliott Aviation Technical Products 
Development, Inc. These special conditions will require that the new 
EFIS that performs 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 avionic/electronic 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 (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 Elliott Aviation Technical Products Development, 
Inc. Should Elliott Aviation Technical Products Development, Inc., 
apply at a later date for a supplemental type certificate to modify any 
other model included on Type Certificate No. A3EU to incorporate 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), 
Amendment 21-69, effective September 16, 1991.

Conclusion

    This action affects only certain novel or unusual design features 
on Raytheon Aircraft Company Model HS.125 Series 700A airplanes 
modified by Elliott Aviation Technical Products Development, 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 this airplane.
    The substance of the special conditions for this airplane has been 
subjected to the 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

[[Page 257]]

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 Elliott Aviation 
Technical Products Development, 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 December 23, 2002.
Charles Huber,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-63 Filed 1-2-03; 8:45 am]
BILLING CODE 4910-13-P