[Federal Register Volume 61, Number 129 (Wednesday, July 3, 1996)]
[Rules and Regulations]
[Pages 34716-34718]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-16959]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-127; Special Conditions No. 25-ANM-117]
Special Conditions: Cessna Model 500, 550, and S550 Airplanes;
High-Intensity Radiated Fields
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued for the Cessna Model 500,
550, and S550 airplanes. These airplanes, as modified by Columbia
Avionics, Inc., utilize new avionics/electronic systems, such as an
electronic flight information system (EFIS), which 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). These special
conditions contain 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 these special conditions is June 20, 1996.
Comments must be received on or before August 2, 1996.
ADDRESSES: Comments on these special conditions may be mailed in
duplicate to: Federal Aviation Administration, Office of the Assistant
Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-127, 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-127. 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, ANM-113, Transport Airplane
Directorate, Aircraft Certification Service, 1601 Lind Avenue SW.,
Renton, Washington, 98055-4056; telephone (206) 227-2145; facsimile
(206) 227-1149.
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
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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. These special conditions 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 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-127.'' The postcard will be date stamped and returned to the
commenter.
Background
On April 8, 1996, Columbia Avionics, 11200 Airport Road, Columbia,
MO 65201, applied for a Supplemental Type Certificate (STC) to modify
Cessna 500, 550, and S550 airplanes to incorporate the installation of
an electronic flight instrument system (EFIS). The airplanes are
pressurized, executive transport airplanes powered by two fuselage-
mounted turbofan engines.
Supplemental Type Certification Basis
Under the provisions of Sec. 21.101 of 14 CFR part 21, Columbia
Avionics must show that the modified Cessna 500, 550, and S550
airplanes continue to meet the applicable provisions of the regulations
incorporated by reference in Type Certificate 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 TC A22CE include the following
for the Cessna 500, 550 and S550 series: 14 CFR part 25, dated February
1, 1965, as amended by Amendments 25-1 through 25-17, and Secs. 25.934
and 25.1091(d)(2), as amended through Amendment 25-23. In addition,
under Sec. 21.101(b)(1), the following regulations apply to the EFIS
installation: Secs. 25.1303, 25.1305, and 25.1322, as amended by
Amendment 25-38; Secs. 25.1309, 25.1321 (a), (b), (d), and (e),
25.1331, 25.1333, and 25.1335, as amended by Amendment 25-41; and
Sec. 25.1316, as amended by Amendment 25-80. These special conditions
form an additional part of the 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 Model 500, 550, and S550
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
14 CFR Sec. 11.49 after public notice, as required by Secs. 11.28 and
11.29(b), 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).
Novel or Unusual Design Features
The Cessna Model 500, 550, and S550 airplanes incorporate new
avionics/electronic systems, such as the electronic flight instrument
system (EFIS), that perform critical functions. These systems may be
vulnerable to high-intensity radiated fields (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 Cessna Model 500, 550, and S550, as
modified by Columbia Avionics, which requires that new electrical and
electronic systems, such as the EFIS, 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, such as the EFIS, 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
Frequency M) (V/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, these special conditions are applicable to the
Cessna Model 500, 550, and S550 airplanes, as modified by Columbia
Avionics, Inc. Should Columbia Avionics 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, 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 Cessna
Model 500, 550, and S550 airplanes. It is not a rule of general
applicability and affects only the applicant who applied to the FAA
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for approval of these features on the airplane.
The substance of the special conditions for this airplane has been
subject 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 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. 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 type certification basis for Cessna Model 500, 550, and S550
airplanes, as modified by Columbia Avionics, 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 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, in June 20, 1996.
Gary L. Killion,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 96-16959 Filed 7-2-96; 8:45 am]
BILLING CODE 4910-13-M
