[Federal Register Volume 60, Number 38 (Monday, February 27, 1995)]
[Rules and Regulations]
[Pages 10486-10488]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4773]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 25
[Docket No. NM-108; Special Conditions No. 25-ANM-96]
Special Conditions: Modified Gulfstream American Corporation
Model G-IV 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 for the Gulfstream
American Corporation (GAC) Model G-IV airplane modified by Duncan
Aviation, Inc., of Lincoln, Nebraska. This airplane will be equipped
with a Flight Visions Corporation, FV-2000 Head-Up Display System (HUD)
that will perform critical functions. The applicable regulations do not
contain adequate or appropriate safety standards for the protection of
the HUD from the effects of high-intensity radiated fields (HIRF).
These special conditions provide the additional safety standards that
the Administrator considers necessary to ensure that the critical
functions performed by this system are maintained when the airplane is
exposed to HIRF.
DATES: The effective date of these special conditions is February 13,
1995. Comments must be received on or before April 13, 1995.
ADDRESSES: Comments on these final special conditions, request for
comments, may be mailed in duplicate to: Federal Aviation
Administration, Office of the Assistant Chief Counsel, Attn: Rules
Docket (ANM-7), Docket No. NM-108, 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-108.'' 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:
Mark Quam, FAA, Standardization Branch, Transport Airplane Directorate,
Aircraft Certification Service, 1601 Lind Avenue SW., Renton,
Washington, 98055-4056; telephone (206) 227-2145.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that good cause exists for making these
special conditions 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 conditions 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. These
special conditions may be changed in light of the comments received.
All [[Page 10487]] 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
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-108.'' The postcard will
be date stamped and returned to the commenter.
Background
On August 16, 1994, Duncan Aviation, Inc., of Lincoln, Nebraska,
applied for a supplemental type certificate to modify the Gulfstream
American Corporation (GAC) Model G-IV airplane. The GAC Model G-IV
airplane is a business jet with two aft-mounted turbofan engines. The
airplane can carry two pilots and 19 passengers, depending on the exit
and interior configuration, and is capable of operating to an altitude
of 45,000 feet. The proposed modification incorporates the installation
of a digital avionics system that will present critical functions on
the Head-up Display System (HUD), which is potentially vulnerable to
high-intensity radiated fields (HIRF) external to the airplane.
Supplemental Type Certification Basis
Under the provisions of Sec. 21.101 of the Federal Aviation
Regulations (FAR), Duncan Aviation, Inc., must show that the altered
GAC Model G-IV airplane continues to meet the applicable provisions of
the regulations incorporated by reference in Type Certificate No.
A12EU, 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 incorporated by reference in Type Certificate No.
A12EU include the following for the GAC Model G-IV airplanes:
Sec. 21.29 of 14 CFR part 21 and 14 CFR part 25, dated February 1,
1965, as amended by Amendments 25-1 through 25-26. In addition, under
Sec. 21.101(b)(1), the following sections of the FAR apply to the HUD
installation: Sec. 25.1322, as amended by Amendment 25-38; and
Secs. 25.1309, 25.1321(a)(b) (d), and (e), 25.1331, 25.1333, and
25.1335, as amended by Amendment 25-41. These special conditions will
form an additional part of the supplemental type certification basis.
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 GAC Model G-IV airplane 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 applicant 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,
the special conditions would also apply to the other model under the
provisions of Sec. 21.101(a)(1).
Discussion
There is no specific regulation that addresses protection
requirements for electrical and electronic systems from high-intensity
radiated fields (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, special
conditions are needed for the modified GAC Model G-IV airplanes that
would require that the HUD be designed and installed to preclude
component damage and interruption of function due to the 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, such as the HUD, to HIRF
must be established.
It is not possible to precisely define the HIRF to which the
airplanes 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:
------------------------------------------------------------------------
Peak (V/ Average
Frequency M) (V/M)
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10 KHz-100 KHz...................................... 50 50
100 KHz-500 KHz..................................... 60 60
500 KHz-2000 KHz.................................... 70 70
2 MHz-30 MHz........................................ 200 200
30 MHz-70 MHz....................................... 30 30
70 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-1000 MHz.................................... 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, these special conditions are applicable to the
GAC Model G-IV airplane, modified by Duncan Aviation. Should Duncan
Aviation apply at a later date for a supplemental type certificate to
modify any other model included on Type Certificate No. A12EU to
incorporate the same novel or unusual design feature, the special
conditions would apply to that model as well, under the provisions of
Sec. 21.101(a)(1).
Conclusion
This action affects only certain unusual or novel design features
on GAC Model G-IV airplanes modified by Duncan Aviation. It is not a
rule of general applicability and affects only the applicant who
applied to the FAA for approval of this feature on this 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. It is
unlikely that prior public comment [[Page 10488]] 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 immediately. Therefore, these special conditions are 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 these special conditions is as follows:
Authority: 49 U.S.C. app. 1344, 1348(c), 1352, 1354(a), 1355,
1421 through 1431, 1502, 1651(b)(2), 42 U.S.C. 1857f-10, 4321 et
seq.; E.O. 11514; and 49 U.S.C. 106(g).
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 GAC Model G-IV
airplane, as modified by Duncan Aviation:
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 external to the airplane.
2. The following definition applies with respect to this special
condition: Critical Function. 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 February 13, 1995.
Darrell M. Pederson,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service, ANM-101.
[FR Doc. 95-4773 Filed 2-24-95; 8:45 am]
BILLING CODE 4910-13-M
