[Federal Register Volume 70, Number 194 (Friday, October 7, 2005)]
[Rules and Regulations]
[Pages 58605-58607]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-20175]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM330; Special Conditions No. 25-301-SC]


Special Conditions: Raytheon Model HS.125 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 a Raytheon Model 
HS.125 airplane modified by LJSC Ltd. This modified airplane 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 
two Air Data Display Units and two Air Data Sensors manufactured by 
Innovative Solutions and Support. These systems perform critical 
functions. 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 established by the existing airworthiness standards.

DATES: The effective date of these special conditions is September 29, 
2005.
    Comments must be received on or before November 7, 2005.

ADDRESSES: Comments on these special conditions may be mailed in 
duplicate to: Federal Aviation Administration, Transport Airplane 
Directorate, Attention: Rules Docket (ANM-113), Docket No. NM330, 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. NM330.

FOR FURTHER INFORMATION CONTACT: Greg Dunn, FAA, Airplane and Flight 
Crew Interface Branch, ANM-111, Transport Airplane Directorate, 
Aircraft Certification Service, 1601 Lind Avenue SW., Renton, 
Washington 98055-4056; telephone (425) 227-2799; facsimile (425) 227-
1320.

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 11, 2005, LJSC Ltd., 8847 West Monroe Circle, Suite 300, 
Wichita, Kansas 67209 applied for a supplemental type certificate (STC) 
to modify a Raytheon Model HS.125 Series 600A airplane, S/N 256066. 
This model is currently approved under Type Certificate No. A3EU. The 
Raytheon Model HS.125 airplane is a small transport category airplane 
powered by two turbine engines. It operates with a 2-pilot crew and can 
seat up to 15 passengers. The modification incorporates the 
installation of two Air Data Display Units (ADDUs) and two Air Data 
Sensors (ADSs) manufactured by Innovative Solutions and Support (IS&S). 
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 21.101, LJSC Ltd. must show that 
Raytheon Model HS.125 Series 600A airplane S/N 256066, as changed, 
continues 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 Raytheon Model 
HS.125 airplane includes CAR 10, British Civil Airworthiness 
Requirements and Special Conditions. This certification is equivalent 
to CAR.4b dated December 1953, Amendment 4b-1 through Amendment 4b-11, 
exclusive of CAR 4b.350(e) and includes Special Regulations SR.422B. 
Type Certificate No. A3EU was amended to include HS.125 Series 600A on 
January 6, 1976. Compliance over and above certification basis 
requirements has been met with CAR Amendment 4B-12 and Amendment 4B-14. 
Compliance has been established with the special retroactive 
requirements of 14 CFR 25.2 through Amendment 25-20, 14 CFR 21 
Amendment 21-27, and 14 CFR 36 (1)(c)(2).
    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 Model HS.125 Series 600A 
airplane, S/N 256066, 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, Raytheon Model HS.125 Series 600A airplane, S/N 256066, 
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

[[Page 58606]]

certification basis in accordance with Sec.  21.101.
    Special conditions are initially applicable to the model for which 
they are issued. Should LJSC Ltd. apply at a later date for a STC to 
modify any other model included on Type Certificate No. 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.

Novel or Unusual Design Features

    As noted earlier, Raytheon Model HS.125 airplane, S/N 256066, 
modified by LJSC Ltd., will incorporate two ADDUs and two ADSs 
manufactured by IS&S that will perform critical functions. These 
systems may be vulnerable to 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 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 Raytheon Model HS.125 Series 600A airplane, 
S/N 256066, modified by LJSC Ltd. 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, and the advent of space and satellite communications 
coupled with electronic command and control of the airplane, 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 (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 
identified in the table below 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 a 
Raytheon Model HS.125 Series 600A airplane, S/N 256066, modified by 
LJSC Ltd. Should LJSC Ltd. apply at a later date for a STC to modify 
any other model included on Type Certificate No. A3EU to incorporate 
the same or similar novel or unusual design feature, these special 
conditions would apply to that model as well under the provisions of 
Sec.  21.101.

Conclusion

    This action affects only certain novel or unusual design features 
on a Raytheon Model HS.125 Series 600A airplane, S/N 256066, modified 
by LJSC Ltd. 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 these special conditions has been subjected to the 
notice and comment procedure in several prior instances and has been 
derived without substantive change

[[Page 58607]]

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 the Raytheon Model HS.125 
Series 600A airplane, S/N 256066, modified by LJSC Ltd.
    1. Protection from Unwanted Effects of 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 29, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 05-20175 Filed 10-6-05; 8:45 am]
BILLING CODE 4910-13-P