[Federal Register Volume 60, Number 38 (Monday, February 27, 1995)]
[Rules and Regulations]
[Pages 10482-10483]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4772]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 25
[Docket No. NM-107; Special Conditions No. 25-ANM-95]
Special Conditions; Modified Cessna 550 Series Airplanes; High
Intensity Radiated Fields (HIRF)
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final special conditions with request for comments.
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SUMMARY: These special conditions are issued for Cessna 550 series
airplanes modified by Elliott Aviation Technical Products Development,
Inc. of Moline Illinois. These airplanes are equipped with digital
head-up display (HUD) systems that perform critical functions. The
applicable type certification 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 provide the additional safety standards that the
Administrator considers necessary to ensure that the critical functions
that these systems perform 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 special conditions may be mailed in
duplicate to: Federal Aviation Administration, Transport Airplane
Directorate (ANM-100), Attn: Docket No. NM-107, 1601 Lind Avenue SW.,
Renton, WA 98055-4056; or delivered in duplicate to the Transport
Airplane Directorate at the above address. Comments must be marked:
Docket No. NM-107. 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:
Michael Zielinski, FAA, Standardization Branch, ANM-113, Transport
Airplane Directorate, Aircraft Certification Service, 1601 Lind Avenue
SW., Renton, WA 98055-4056; telephone (206) 227-2279.
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 or
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 comments submitted will be available in the 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-107.'' The postcard will be date
stamped and returned to the commenter.
Background
On October 25, 1994, Elliott Aviation Technical Products
Development, Inc. of Moline, Illinois, applied for a supplemental type
certificate to modify Cessna 550 series airplanes. The Cessna 550 is a
business jet with two aft-mounted turbofan engines. The airplane can
carry two pilots and up to 11 passengers, depending on the exit and
interior configuration, and is capable of operating to an altitude of
43,000 feet. The proposed modification incorporates the installation of
digital avionics consisting of a head-up display (HUD) system that is
potentially vulnerable to HIRF external to the airplane.
Supplemental Type Certification Basis
Under the provisions of Sec. 21.101 of the FAR, Elliott Aviation
Technical Products Development, Inc. must show that the modified Cessna
550 series airplanes continue to meet the applicable provisions of the
regulations incorporated by reference in Type Certificate No. A22CE, 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.
A22CE include the following: Part 25 of the Federal Aviation
Regulations (FAR), dated February 1, 1965, including Amendments 25-1
through 25-17. In addition the following sections of the FAR apply to
the HUD installation: Secs. 25.1303(b) and 25.1322, as amended through
Amendment 25-38; Secs. 25.1309, 25.1321 (a), (b), (d), and (e),
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 Cessna 550 series airplanes
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 [[Page 10483]] 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 address 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, special
conditions are needed for the Cessna 550 series airplanes that would
require that new technology electrical and electronic systems, such as
the HUD, 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, such as the HUD, 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.
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Peak(V/ Average(V/
Frequency 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-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-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, these special conditions are applicable to
Cessna 550 series airplanes, modified by Elliott Aviation Technical
Products Development, Inc. Should Elliott Aviation Technical Products
Development, Inc. apply at a later date for a supplemental type
certificate to modify any other model included on Type Certificate No.
A22CE 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 Cessna 550 series airplanes modified by Elliott Aviation Technical
Products Development, Inc. of Moline, Illinois. It is not a rule of
general applicability and affects only the applicant who applied to the
FAA for approval of these features on modified Cessna 550 series
airplanes.
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. 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 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 have not 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 condition is issued as part of the
supplemental type certification basis for Cessna 550 series airplanes
modified by Elliott Aviation Technical Products Development, 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 external to the airplane.
2. The following definition applies with respect to this special
condition: 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 February 13, 1995.
Darrell M. Pederson,
Assistant Manager, Transport Airplane Directorate, Aircraft
Certification Service, ANM-101.
[FR Doc. 95-4772 Filed 2-24-95; 8:45 am]
BILLING CODE 4910-13-M
