[Federal Register Volume 68, Number 236 (Tuesday, December 9, 2003)]
[Rules and Regulations]
[Pages 68499-68501]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-30447]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM269; Special Conditions No. 25-253-SC]


Special Conditions: Israel Aircraft Industries Model 1124 
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 Israel Aircraft 
Industries Model 1124 airplanes modified by Garrett Aviation Services. 
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 dual Innovative Solutions 
& Support (IS&S) Air Data Display Unit systems with the IS&S Air Data 
Sensor that 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 November 24, 
2003.
    Comments must be received on or before January 8, 2004.

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. NM269, 1601 Lind 
Avenue, SW., Renton, Washington 98055-4056; or delivered in duplicate 
to the Transport Directorate at the above address. All comments must be 
marked: Docket No. NM269.

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 the notice and opportunity for public 
comment is impracticable because these procedures would significantly 
delay certification of the airplane and delivery of the affected 
airplane. 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 commit 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 thru Friday, 
except Federal holidays.

[[Page 68500]]

    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 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 September 26, 2003, Garrett Aviation Services, 1200 North 
Airport Drive, Capital Airport Springfield, IL 62707, applied for a 
Supplemental Type Certificate (STC) to modify Israel Aircraft 
Industries (IAI) Model 1124 airplanes approved under Type Certificate 
No. A2SW. The IAI Model 1124 is a small transport category airplane. 
The IAI Model 1124 airplane is powered by two AiResearch Manufacturing 
Company TFE731-3-1G turbofans and has a maximum takeoff weight of 
23,500 pounds. This airplane operates with a 2-pilot crew and can hold 
up to 10 passengers. The modification incorporates the installation of 
dual Innovative Solutions & Support Air Data Display Units (ADDU) and a 
single IS&S Air Data Sensor (ADS) interfaced with an existing Collins 
AP-105 Autopilot. The ADDU is a replacement for the existing analog 
flight instrumentation, while also providing additional functional 
capability and redundancy in the system. The ADS is a digital 
replacement for the existing analog Collins 590A-3( ) Air Data 
Controller which outputs vertical and lateral mode signals to the 
Collins flight guidance system. The digital avionics/electronics and 
electrical systems installed under this project 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, Garrett Aviation Services 
must show that the IAI Model 1124 airplanes, as changed, continue to 
meet the applicable provisions of the regulations incorporated by 
reference in Type Certificate No. A2SW, 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 IAI Model 1124 airplanes include 14 CFR Part 25, 
dated February 1, 1964, as amended by Amendments 25-1 through 25-20 
except for special conditions and exceptions noted in Type Certificate 
Data Sheet (TDCS) A2SW.
    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 IAI Model 1124 airplanes 
because of novel or unusual design features, special conditions are 
prescribed under the provisions Sec.  21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the IAI Model 1124 airplanes must comply with the 
associated change requirements of Sec.  21.93(b).
    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.
    Special conditions are initially applicable to the model for which 
they are issued. Should Garrett Aviation Services apply at a later date 
for a supplemental type certificate to modify any other model included 
on the same type certificate 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 14 CFR 21.101.

Novel or Unusual Design Features

    The IAI Model 1124 airplanes modified by Garrett Aviation Services 
will incorporate dual Air Data Display Units and a single Air Data 
Sensor system that will perform critical functions. These systems have 
to potential to be vulnerable to high-intensity radiated fields (HIRF) 
external to the airplane. The current airworthiness standards (part 25) 
do not contain adequate or appropriate safety standards for the 
protection of this equipment from the adverse effect 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 that is equivalent to 
that intended by the regulations incorporated by reference; special 
conditions are needed for IAI Model 1124 airplanes modified by Garrett 
Aviation Services. 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, plus 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 following field 
strengths for the frequency ranges indicated. Both peak and average 
field strength components from the Table are to be demonstrated.

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                                                       Field Strength
                                                      (volts per meter)
                     Frequency                     ---------------------
                                                       Peak     Average
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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

[[Page 68501]]

 
12 GHz-18 GHz.....................................       2000        200
18 GHz-40 GHz.....................................        600       200
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 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 IAI 
Model 1124 airplanes modified by Garret Aviation Services. Should 
Garrett Aviation Services apply at a later date for a supplemental type 
certificate to modify any other model included on the same type 
certificate 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 the IAI Model 1124 airplanes modified by Garrett Aviation Services. 
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 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 to 
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 Israel Aircraft 
Industries Model 1124 airplanes modified by Garrett Aviation Services.
    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 November 24, 2003.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 03-30447 Filed 12-8-03; 8:45 am]
BILLING CODE 4910-13-P