[Federal Register Volume 68, Number 109 (Friday, June 6, 2003)]
[Rules and Regulations]
[Pages 33834-33836]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-14336]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM256, Special Conditions No. 25-236-SC]


Special Conditions: Raytheon Model HS.125 Series 700A and 700B 
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 Model HS.125 
Series 700A and 700B airplanes modified by Raytheon Aircraft Services, 
Inc. These modified airplanes will have a novel or 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 a Rockwell Collins AFD 
2000 Electronic Flight Instrument System (EFIS) that performs critical 
functions. The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for the protection of this 
system 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 May 22, 2003. 
Comments must be received on or before July 7, 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. NM256, 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. NM256.

FOR FURTHER INFORMATION CONTACT: Connie Beane, FAA, Standardization 
Branch, ANM-113, Transport Airplane Directorate, 1601 Lind Avenue SW., 
Renton, Washington, 98055-4056; telephone (425) 227-2796; facsimile 
(425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

    The FAA has determined that notice and opportunity for public 
comment in accordance with 14 CFR 11.38 are unnecessary, because the 
FAA has provided previous opportunities to comment on substantially 
identical special conditions and has fully considered and addressed all 
the substantive comments received. Based on a review of the comment 
history and the comment resolution, the FAA is satisfied that new 
comments are unlikely. 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 received.
    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 September 23, 2002, Raytheon Aircraft Services, Inc., 1115 Paul 
Wilkins Road, San Antonio, Texas 78216, applied for a supplemental type 
certificate (STC) to modify Raytheon Model HS.125 Series 700A and 700B 
airplanes. These models are currently approved under Type Certificate 
No. A3EU. The HS.125 Series 700A and 700B airplanes are two flightcrew, 
two-engine airplanes, each with a maximum takeoff weight of 25,500 lbs. 
The modification incorporates the installation of a Rockwell Collins 
AFD 2000 EFIS. This equipment will replace the equipment originally 
installed in these airplanes which presents the required flight 
information in the form of analog displays. The avionics/electronics 
and electrical system to be installed has the potential to be 
vulnerable to high-intensity radiated fields (HIRF) external to the 
airplane.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Amendment 21-69, effective 
September 16, 1991, Raytheon Aircraft Services, Inc. must show that the 
modified Model HS.125 Series 700A and 700B airplanes, as modified, 
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. Subsequent changes have been made to Sec.  21.101 as part of 
Amendment 21-77, but those changes do not become effective until June 
10, 2003. The regulations incorporated by reference in the type 
certificate are commonly referred to as the ``original type 
certification basis.''
    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 Model HS.125 Series 700A and 700B 
airplanes because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Raytheon Model HS.125 Series 700A and 700B airplanes 
must comply with the fuel vent and exhaust emission requirements of 14 
CFR part 34 and the noise certification requirements of 14 CFR 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), Amendment 21-69, effective 
September 16, 1991.

[[Page 33835]]

    Special conditions are initially applicable to the model for which 
they are issued. Should Raytheon Aircraft Services, Inc. apply at a 
later date for a supplemental type certificate to modify any other 
model included on Type Certificate A3EU to incorporate the same or 
similar novel or unusual design feature, these 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 Raytheon Model HS.125 Series 700A and 700B 
airplanes modified by Raytheon Aircraft Services, Inc. will incorporate 
an EFIS that will perform critical functions. This system may be 
vulnerable to high-intensity radiated fields 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 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 Model HS.125 Series 700A and 
700B airplanes modified by Raytheon Aircraft Services, Inc. These 
special conditions require that new avionic/electronic 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 and 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 following table 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.

Applicability

    As discussed above, these special conditions are applicable to 
Raytheon Model HS.125 Series 700A and 700B airplanes modified by 
Raytheon Aircraft Services, Inc. Should Raytheon Aircraft Services, 
Inc. apply at a later date for a supplemental type certificate to 
modify any other model included on Type Certificate A3EU to incorporate 
the same or similar novel or unusual design feature, these special 
conditions would apply to that model as well as 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 the Raytheon Model HS.125 Series 700A and 700B airplanes modified by 
Raytheon Aircraft Services, Inc. It is not a rule of general 
applicability and affects only the applicant which applied

[[Page 33836]]

to the FAA for approval of these features on the airplane.
    The FAA has determined that notice and opportunity for public 
comment in accordance with 14 CFR 11.38 are unnecessary, because the 
FAA has provided previous opportunities to comment on substantially 
identical special conditions and has fully considered and addressed all 
the substantive comments received. Based on a review of the comment 
history and the comment resolution, the FAA is satisfied that new 
comments are unlikely. The FAA, therefore, finds that good cause exists 
for making these special conditions effective upon issuance.

List of Subjects in 14 CFR Part 25

    Aircraft, Aviation safety, Reporting and record keeping 
requirements.

0
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 the Raytheon Model HS.125 
Series 700A and 700B airplanes modified by Raytheon Aircraft Services, 
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 May 22, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-14336 Filed 6-5-03; 8:45 am]
BILLING CODE 4910-13-P