[Federal Register Volume 67, Number 116 (Monday, June 17, 2002)]
[Rules and Regulations]
[Pages 41157-41160]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-15196]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM219, Special Conditions No. 25-204-SC]
Special Conditions: Israel Aircraft Industries, Ltd. Model 1124/
1124A 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, Ltd. Model 1124/1124A airplanes modified by Duncan
Aviation. These airplanes, as
[[Page 41158]]
modified by Duncan Aviation, 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 a dual Collins AHS-3000A
Attitude Heading Reference System (AHRS). 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 June 6, 2002.
Comments must be received on or before July 17, 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. NM219, 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. NM219. 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: 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-
1149.
SUPPLEMENTARY INFORMATION: The FAA has determined that notice and
opportunity for prior public comment hereon are impracticable because
these procedures would significantly delay certification, and thus
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 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 March 28, 2002, Duncan Aviation, Inc., P.O. Box 81887, Lincoln,
NE 68501, applied for a supplemental type certificate (STC) to modify
Israel Aircraft Industries Ltd. Model 1124/1124A airplanes approved
under Type Certificate No. A2SW. The Israel Aircraft Industries, Ltd.
1124/1124A airplanes are executive type transports that have two aft
mounted turbine engines, a maximum passenger load of 10 passengers, and
a maximum operating speed of 360 knots. The modification incorporates
the installation of a dual Collins AHS-3000A Attitude Heading Reference
System (AHRS). The AHS-3000A is a solid state, strap-down attitude/
heading reference system using quartz based inertial sensor technology.
Its primary function is to provide measurements of the airplane's
pitch, roll, and heading for use by cockpit displays, flight control
and management systems, and other avionics equipment. The basic AHS-
3000A system consists of a Collins AHC-3000A Attitude/Heading Computer,
a Collins FDU-3000 Flux Detector, and a Collins ECU-3000 External
Compensation Unit. These advanced systems use electronics to a far
greater extent than the original inertial navigation systems and may be
more susceptible to electrical and magnetic interference caused by
high-intensity radiated fields (HIRF). This disruption of signals could
result in loss of attitude or the display of misleading information to
the pilot.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Duncan Aviation, Inc. must
show that the Israel Aircraft Industries, Ltd. Model 1124/1124A
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, Ltd. Model 1124/1124A airplanes includes Civil Air
Regulations (CAR) 4b, effective December 31, 1953, including amendments
through amendment level 4b-11. Other applicable amendments, Federal
Aviation Regulations, and special conditions are noted in Type
Certificate Data Sheet (TCDS) A2SW.
If the Administrator finds that the applicable airworthiness
regulations (that is, CAR 4b or 14 CFR part 25, as amended) do not
contain adequate or appropriate safety standards for the Israel
Aircraft Industries, Ltd. Model 1124/1124A 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 Israel Aircraft Industries, Ltd. Model 1124/1124A
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 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).
Special conditions are initially applicable to the model for which
they are issued. Should Duncan Aviation, Inc. apply at a later date for
a supplemental type certificate to modify any other model already
included on the same type certificate to incorporate the same novel or
unusual design features, these special conditions would also apply to
the other model under the provisions of 14 CFR 21.101(a)(1).
Novel or Unusual Design Features
The Israel Aircraft Industries, Ltd. Model 1124/1124A airplanes
will incorporate a dual Collins AHS-3000A Attitude Heading Reference
System, which performs critical functions. Each system consists of a
Collins AHC-3000A Attitude/Heading Computer, a Collins
[[Page 41159]]
FDU-3000 Flux Detector Unit, and a Collins ECU-3000 External
Compensation Unit. Because these advanced systems use electronics to a
far greater extent than the original inertial 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 (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 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 Israel Aircraft Industries, Ltd. Model
1124/1124A airplanes modified to include the new navigation system.
These special conditions will require that the new Collins Avionics
AHS-3000A Attitude Heading Reference Systems, 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/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 in accordance 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.
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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
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.
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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
Israel Aircraft Industries, Ltd. Model 1124/1124A airplanes modified by
Duncan Aviation, Inc. to include the Collins AHS-3000A Attitude Heading
Reference Systems. Should Duncan Aviation, Inc. apply at a later date
for a supplemental type certificate to modify any other model already
included on Type Certificate A2SW to incorporate the same novel or
unusual design features, these special conditions would apply to that
model as well under the provisions of 14 CFR 21.101(a)(1).
Conclusion
This action affects only certain design features on Israel Aircraft
Industries, Ltd. Model 1124/1124A 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 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
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 Israel Aircraft
Industries, Ltd. Model 1124/1124A airplanes modified by Duncan
Aviation, 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.
[[Page 41160]]
Issued in Renton, Washington, on June 6, 2002.
Ali Bahrami,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 02-15196 Filed 6-14-02; 8:45 am]
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