[Federal Register Volume 67, Number 101 (Friday, May 24, 2002)]
[Rules and Regulations]
[Pages 36507-36509]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-13132]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 25

[Docket No. NM221, Special Conditions No. 25-203-SC]


Special Conditions: Israel Aircraft Industries (IAI) Model 1124 
Airplane; High-Intensity Radiated Fields (HIRF)

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued Israel Aircraft Industries 
(IAI) Model 1124 airplanes modified by Duncan Aviation, Inc. These 
modified 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 modification 
incorporates the installation of an air data display unit that displays 
critical flight parameters to the flightcrew. The applicable 
airworthiness standards do not contain adequate or appropriate safety 
standards for the protection of these systems from the effects of high-
intensity radiated fields. The 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 16, 2002. 
Comments must be received on or before June 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. NM221, 1601 Lind 
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate 
to the Transport Airplane Directorate at the above address. Comments 
must be marked: Docket No. NM221. Comments may be inspected in the 
Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 
p.m.

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: The FAA has determined that notice and 
opportunity for prior public comment hereon are impracticable because 
these procedures would significantly delay issuance of the approval 
design and thus delivery of the affected airplanes. 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.

Comments Invited

    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 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 April 12, 2002, Duncan Aviation, Inc., 15745 South Airport Road, 
Battle Creek, MI, 49015, applied for a supplemental type certificate 
(STC) to modify the Israel Aircraft Industries (IAI) Model 1124 
airplane listed on Type Certificate No. A2SW. The Model 1124 is a twin 
engine, small transport airplane. It is capable of carrying two 
flightcrew members and up to ten passengers. The modification 
incorporates the installation of an air data display system. The air 
data display system displays critical flight parameters to the 
flightcrew. These systems can be susceptible to disruption to command 
and/or response signals as a result of electrical and magnetic 
interference. This disruption of signals could result in loss of all 
critical flight displays and announcement functions or present 
misleading information to the pilot.

Type Certification Basis

    Under the provisions of 14 CFR 21.101, Duncan Aviation must show 
that the Israel Aircraft Industries 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 Israel 
Aircraft Industries Model 1124 airplane includes Civil Aviation 
Regulations (CAR) 4b, effective 31 December 1953, including amendments 
through 4b-11, 4b-12, paragraphs 4b.132(e), 4b.151(a), 4b.155, 4b.156, 
4b.157, 4b.158, 4b.160, 4b.162, 4b.191, 4b.210(b)(5), 4b.603(k), 
4b.711, and paragraphs pertaining to engine fire shielding 14 CFR part 
25, dated February 1, 1965, including Amendments 25-1 through 25-20, as 
listed in the Type Certificate Data Sheet (TCDS) No. A2SW.
    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 Israel Aircraft Industries Model 
1124 airplane because of a novel or unusual design feature, special 
conditions are prescribed under the provisions of [sect] 21.16.
    In addition to the applicable airworthiness regulations and special 
conditions, the Model 1124 airplane

[[Page 36508]]

must comply with the part 25 fuel vent and exhaust emission 
requirements of 14 CFR part 34 and the part 25 noise certification 
requirements of 14 CFR part 36.
    Special conditions, as defined in [sect] 11.19, are issued in 
accordance with [sect] 11.38 and become part of the type certification 
basis in accordance with [sect] 21.101(b)(2).
    Special conditions are initially applicable to the model for which 
they are issued. Should Duncan Aviation, Inc. apply for a supplemental 
type certificate to modify any other model included on the same type 
certificate to incorporate the same novel or unusual design feature, 
these special conditions would also apply to the other model under the 
provisions of [sect] 21.101(a)(1).

Novel or Unusual Design Features

    The Israel Aircraft Industries Model 1124 airplane will incorporate 
an air data display unit that displays critical flight parameters to 
the flightcrew. These systems can be susceptible to disruption to 
command and/or response signals as a result of electrical and magnetic 
interference. This disruption of signals could result in loss of all 
critical flight displays and announcement functions or present 
misleading information to the pilot. 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 avionic/electronic 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 Israel Aircraft Industries Model 1124, as 
modified by Duncan Aviation, Inc. These special conditions require that 
new avionic/electronic and electrical systems such as the air data 
display unit, which 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 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 paragraph 2, below:
    1. A minimum threat of 100 volts rms 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.

                                 Table 1
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                                                       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
400MHz-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 the 
Israel Aircraft Industries Model 1124 airplane modified by Duncan 
Aviation, Inc. to include the air data display unit. Should Duncan 
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 novel or unusual design feature, these special conditions would 
apply to that model as well under the provisions of [sect] 
21.101(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on Israel Aircraft Industries Model 1124 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 the notice and comment period in several prior instances 
and has been derived without substantive change from those previously 
issued. It is unlikely that prior public comment would result in a 
significant change from the substance contained herein. For this 
reason, and 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 type certification basis for Israel Aircraft Industries Model 1124 
airplanes modified by Duncan Aviation, Inc.

[[Page 36509]]

    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 16, 2002.
Linda Navarro,
Acting Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 02-13132 Filed 5-23-02; 8:45 am]
BILLING CODE 4910-13-P