[Federal Register Volume 70, Number 109 (Wednesday, June 8, 2005)]
[Rules and Regulations]
[Pages 33337-33338]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-11409]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM308, Special Conditions No. 25-289-SC]
Special Conditions: Gulfstream Model LP 1125 Westwind Astra
Airplane; 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 the Gulfstream Model
LP 1125 Westwind Astra airplane modified by Duncan Aviation, Inc. This
airplane will have novel and unusual design features when compared to
the state of technology envisioned in the airworthiness standards for
transport category airplanes. 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 May 19, 2005.
Comments must be received on or before July 8, 2005.
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. NM308, 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. NM308.
FOR FURTHER INFORMATION CONTACT: Joe Jacobsen, FAA, Standardization
Branch, ANM-113, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056;
telephone (425) 227-2011; facsimile (425) 227-1320.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that notice and opportunity for prior public
comment is impracticable because these procedures would significantly
delay certification of and 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.
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 based on the comments we receive.
If you want the FAA to acknowledge receipt of your comments on
these special conditions, 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 February 16, 2005, Duncan Aviation, Inc., Lincoln, Nebraska,
applied to the Wichita Aircraft Certification Office, for a
supplemental type certificate (STC) to modify certain Gulfstream Model
LP 1125 Westwind Astra airplanes to include the installation of
integrated display systems (electronic displays and electronic engine
controls). These integrated display systems installed in this airplane
have the potential to be vulnerable to HIRF external to the airplane.
The subject Gulfstream Model LP 1125 Westwind Astra airplane is a small
business jet powered by two Honeywell (formerly Allied Signal and
Garrett) TFE 731-3A-200G or TFE 731-3C-200G engines. This airplane
operates with a 2-person crew and holds nine passengers.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Duncan Aviation, Inc. must
show that the Gulfstream Model LP 1125 Westwind Astra airplane, as
changed, continues to meet the applicable provisions of the regulations
incorporated by reference in Type Certificate No. 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 certification basis for the modified Gulfstream Model LP
Westwind Astra airplane includes 14 CFR part 25 effective February 1,
1965, as amended by Amendments 25-1 through 25-54. In addition, the
certification basis includes certain special conditions, exemptions,
and equivalent levels of safety that are not relevant to these special
conditions.
If the Administrator finds that the applicable airworthiness
regulations (part 25, as amended) do not contain adequate or
appropriate safety standards for the Gulfstream Model LP 1125 Westwind
Astra airplane, modified by Duncan Aviation, Inc., because of a novel
or unusual design feature, special conditions are prescribed under the
provisions of 14 CFR 21.16. In addition to the applicable airworthiness
regulations and special conditions, the Gulfstream Model LP 1125
Westwind Astra airplane must comply with the fuel vent and exhaust
emission requirements of 14 CFR part 34 and the noise certification
requirements of 14 CFR part 36.
Special conditions, as defined in 14 CFR 11.19, are issued in
accordance with Sec. 11.38, and become part of the airplane's type
certification basis in accordance with Sec. 21.101.
Special conditions are initially applicable to the model for which
they are issued. Should Duncan Aviation, Inc. apply at a later date for
an STC 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 Sec. 21.101.
Novel or Unusual Design Features
The modified Gulfstream LP 1125 Westwind Astra airplane will
incorporate integrated display systems
[[Page 33338]]
(electronic displays and electronic engine controls) that will perform
critical functions. These systems may be vulnerable to HIRF external to
the airplane. The current airworthiness standards of part 25 do not
contain adequate or appropriate safety standards for the protection of
this equipment from the adverse effects 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 equivalent to that
intended by the regulations incorporated by reference, special
conditions are needed for the Gulfstream Model LP 1125 Westwind Astra
airplane. 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, and 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 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
identified in the table below 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
2GHz-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.
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
Gulfstream Model LP 1125 Westwind Astra airplane. Should Duncan
Aviation, Inc., apply at a later date for an STC to modify any other
model included on Type Certificate No. A16NM to incorporate the same or
similar novel or unusual design feature, these special conditions would
apply to that model as well as under the provisions of Sec. 21.101.
Conclusion
This action affects only certain novel or unusual design features
on the Gulfstream Model LP 1125 Westwind Astra airplane. 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 these airplanes 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 immediately. 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 the Gulfstream Model LP
1125 Westwind Astra airplane 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.
Issued in Renton, Washington, on May 19, 2005.
Mike Kaszycki,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-11409 Filed 6-7-05; 8:45 am]
BILLING CODE 4910-13-P