[Federal Register Volume 60, Number 157 (Tuesday, August 15, 1995)]
[Rules and Regulations]
[Pages 42029-42031]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-20151]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-116; Special Condition No. 25-ANM-104]
Special Condition: Israel Aircraft Industries (IAI), Model Astra
SPX, High-Intensity Radiated Fields
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final special condition; request for comments.
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SUMMARY: This special condition is issued for the Israel Aircraft
Industries (IAI) Model Astra SPX airplane. This new airplane utilizes
new avionics/electronic systems, such as electronic displays and
electronic engine controls, that perform critical functions. The
applicable regulations do not contain adequate or appropriate safety
standards for the protection of these systems from the effects of high-
intensity radiated fields (HIRF). This special condition contains 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 this special condition is July 26, 1995.
Comments must be received on or before September 14, 1995
ADDRESSES: Comments on this special condition may be mailed in
duplicate to: Federal Aviation Administration, Office of the Assistant
Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-116, 1601 Lind
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate
to the Office of the Assistant Chief Counsel at the above address.
Comments must be marked: Docket No. NM-116. Comments may be inspected
in the Rules Docket weekdays, except Federal holidays, between 7:30
a.m. and 4:00 p.m.
FOR FURTHER INFORMATION CONTACT: Timothy Dulin, FAA, Standardization
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4506;
telephone (206) 227-2141.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that good cause exists for making this
special condition effective upon issuance; however, interested persons
are invited to submit such written data, views, or arguments as they
may desire. Communications should identify the regulatory docket and
special condition number and be submitted in duplicate to the address
specified above. All communications received on or before the closing
date for comments will be considered by the Administrator. This special
condition may be changed in light of the comments received. All
comments submitted will be available in the Rules Docket for
examination by interested persons, both before and after the closing
date for comments. A report summarizing each substantive public
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contact with FAA personnel concerning this rulemaking will be filed in
the docket. Persons wishing the FAA to acknowledge receipt of their
comments submitted in response to this request must submit with those
comments a self-addressed, stamped postcard on which the following
statement is made: ``Comments to Docket No. NM-116.'' The postcard will
be date stamped and returned to the commenter.
Background
On February 15, 1994, Israel Aircraft Industries (IAI), Ben Gurion
International Airport, Tel Aviv 70100, Israel, applied for an amendment
to Type Certificate (TC) A16NM to incorporate the Model Astra SPX
airplane. The Astra SPX is a derivative of the Model 1125 Westwind
Astra. The changes include installation of new Allied Signal (Garrett)
TFE731-40/40A engines, which are a derivative of the existing TFE731-
3A-200G engines; installation of winglets and minor structural
modifications to the wing; and installation of new avionics.
Type Certification Basis
Under the provisions of Sec. 21.101 of 14 CFR part 21, IAI must
show that the Model Astra SPX meets the applicable regulations
incorporated by reference in TC A16NM, 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 regulations
incorporate by reference in TC A16NM are as follows: Part 25, effective
February 1, 1965, as amended by Amendments 25-1 through 25-54. The
regulations in effect on the date of application include the applicable
provisions of part 25 effective February 1, 1965, as amended by
Amendments 25-1 through 25-79. In addition, the certification basis for
the Model Astra SPX includes part 34, effective September 10, 1990,
plus any amendments in effect at the time of certification; and part
36, effective December 1, 1969, as amended by Amendment 36-1 through
the amendment in effect at the time of certification. This special
condition will form an additional part of the type certification basis.
In addition, the certification basis may include exemptions and other
special conditions that are not relevant to this special condition.
If the Administrator finds that the applicable airworthiness
regulation (i.e., part 25, as amended) do not contain adequate or
appropriate safety standards for the Astra SPX because of a novel or
unusual design feature, special conditions are prescribed under the
provisions of Sec. 21.16 to establish a level of safety equivalent to
that established in the regulations.
Special conditions, as appropriate, are issued in accordance with
Sec. 11.49 of the FAR after public notice, as required by Secs. 11.28
and 11.29, 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 the type certificate for that model be amended
later to include any other model that incorporates the same novel or
unusual design feature, or should any other model already included on
the same type certificate be modified to incorporate the same novel or
unusual design feature, the special conditions would also apply to the
other model under the provisions of Sec. 21.101(a)(1).
Novel or Unusual Design Features
The Model Astra SPX incorporates new avionic/electronic systems,
such as electronic displays and electronic engine controls, that
perform critical functions. These systems may be vulnerable to HIRF
external to the airplane.
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 electrical and electronic 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, a special
condition is needed for the IAI Astra SPX, which would require that new
electrical and electronic 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 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 paragraphs 1, or 2 below:
1. A minimum threat of 100 volts per meter peak 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.
------------------------------------------------------------------------
Average(V/
Frequency Peak(V/M) M)
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10 KHz-100 KHz................................... 50 50
100 KHz-500 KHz.................................. 60 60
500 KHz-2 MHz.................................... 70 70
2 MHz-30 MHz..................................... 200 200
30 MHz-100 MHz................................... 30 30
100 MHz-200 MHz.................................. 150 33
200 MHz-400 MHz.................................. 70 70
400 MHz-700 MHz.................................. 4,020 935
700 MHz-1 GHz.................................... 1,700 170
1 GHz-2 GHz...................................... 5,000 990
2 GHz-4 GHz...................................... 6,680 840
4 GHz-6 GHz...................................... 6,850 310
6 GHz--8 GHz..................................... 3,600 670
8 GHz-12 GHz..................................... 3,500 1,270
12 GHz-18 GHz.................................... 3,500 360
18 GHz-40 GHz.................................... 2,100 750
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As discussed above, this special condition would be applicable
initially to the IAI Model Astra SPX. Should IAI apply at a later date
for a change to the type certificate to include another model
incorporating the same novel or unusual design feature, this special
condition would apply to that model as well, under the provisions of
Sec. 21.101(a)(1).
Conclusion
This action affects only certain design features on the IAI Astra
SPX airplane. It is not a rule of general applicability and affects
only the manufacturer who applied to the FAA for approval of these
features on the airplane.
The substance of the special condition for this airplane has been
subjected to the notice and comment procedure 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
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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 this special condition immediately. Therefore, this special
condition is being made effective 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 this special condition is as follows:
Authority: 49 U.S.C. app. 1344, 1354(a), 1355, 1421, 1423, 1424,
1425, 1428, 1429, 1430, and 49 U.S.C. 106(g).
The Special Condition
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special condition is issued as part of the
type certification basis for the Israel Aircraft Industries (IAI) Model
Astra SPX airplanes.
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 this special condition, 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 July 26, 1995.
Darrell M. Pederson,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 95-20151 Filed 8-14-95; 8:45 am]
BILLING CODE 4910-13-M
