[Federal Register: February 4, 2003 (Volume 68, Number 23)]
[Rules and Regulations]
[Page 5538-5541]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr04fe03-3]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE194, Special Condition 23-134-SC]
Special Conditions; Cirrus Design Corporation SR22; Protection of
Systems for 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 to Cirrus Design
Corporation, 4515 Taylor Circle, Duluth, Minnesota 55811, for a Type
Design Change for the
[[Page 5539]]
Cirrus Design Corporation Model SR22 airplane. This airplane will have
novel and unusual design features when compared to the state of
technology envisaged in the applicable airworthiness standards. These
novel and unusual design features include the installation of
electronic flight instrument system (EFIS) displays Model 700-00006-
XXX-( ) manufactured by Avidyne Corporation for which the applicable
regulations do not contain adequate or appropriate airworthiness
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 the airworthiness
standards applicable to these airplanes.
DATES: The effective date of these special conditions is January 24,
2003. Comments must be received on or before March 6, 2003.
ADDRESSES: Comments may be mailed in duplicate to: Federal Aviation
Administration, Regional Counsel, ACE-7, Attention: Rules Docket Clerk,
Docket No. CE194, Room 506, 901 Locust, Kansas City, Missouri 64106.
All comments must be marked: Docket No. CE194. Comments may be
inspected in the Rules Docket weekdays, except Federal holidays,
between 7:30 a.m. and 4 p.m.
FOR FURTHER INFORMATION CONTACT: Wes Ryan, Aerospace Engineer,
Standards Office (ACE-110), Small Airplane Directorate, Aircraft
Certification Service, Federal Aviation Administration, 901 Locust,
Room 301, Kansas City, Missouri 64106; telephone (816) 329-4127.
SUPPLEMENTARY INFORMATION: The FAA has determined that notice and
opportunity for prior public comment hereon are impracticable because
these procedures would significantly delay issuance of the design
approval and thus delivery of the affected aircraft. 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.
Comments Invited
Interested persons are invited to submit such written data, views,
or arguments as they may desire. Communications should identify the
regulatory docket or notice 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. The
special conditions may be changed in light of the comments received.
All comments received 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. Commenters wishing the FAA to acknowledge receipt of their
comments submitted in response to this notice must include a self-
addressed, stamped postcard on which the following statement is made:
``Comments to Docket No. CE194.'' The postcard will be date stamped and
returned to the commenter.
Background
On July 8, 2002, Cirrus Design Corporation , 4515 Taylor Circle,
Duluth, Minnesota 55811, made an application to the FAA for a Type
Design Change for the Cirrus Design Corporation Model SR22 airplane.
The Model SR22 is currently approved under TC No. A00009CH. The
proposed modification incorporates a novel or unusual design feature,
such as digital avionics consisting of an EFIS, that is vulnerable to
HIRF external to the airplane.
Type Certification Basis
Under the provisions of 14 CFR part 21, Sec. 21.101, Cirrus Design
Corporation must show that the Cirrus Design Corporation Model SR22
aircraft meets the following provisions, or the applicable regulations
in effect on the date of application for the change to the Cirrus
Design Corporation Model SR22: Part 23 of the Federal Aviation
Regulations effective February 1, 1965, as amended by 23-1 through 23-
53, except as follows: Sec. 23.301 through Amendment 47; Sec. Sec.
23.855, 23.1326, 23.1359, not applicable. 14 CFR 36 dated December 1,
1969, as amended by current amendment as of the date of type
Certification.
Equivalent Levels of Safety finding (ACE-96-5) made per the
provisions of 14 CFR part 23, Sec. 23.221; Refer to FAA ELOS letter
dated June 10, 1998 for models SR20, SR22. Equivalent Levels Of Safety
finding (ACE-00-09) made per the provisions of 14 CFR part 23,
Sec. Sec. 23.1143(g) and 23.1147(b); Refer to FAA ELOS letter dated
September 11, 2000 for model SR22.
Special Condition (23-ACE-88) for ballistic parachute; Refer to FAA
letter November 25, 1997 for models SR20, SR22.
Discussion
If the Administrator finds that the applicable airworthiness
standards do not contain adequate or appropriate safety standards
because of novel or unusual design features of an airplane, special
conditions are prescribed under the provisions of Sec. 21.16.
Special conditions, as appropriate, as defined in Sec. 11.19, are
issued in accordance with Sec. 11.38 after public notice 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 already 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.
Novel or Unusual Design Features
Cirrus Design Corporation plans to incorporate certain novel and
unusual design features into an airplane for which the airworthiness
standards do not contain adequate or appropriate safety standards for
protection from the effects of HIRF. These features include EFIS, which
are susceptible to the HIRF environment, that were not envisaged by the
existing regulations for this type of airplane.
Protection of Systems From High Intensity Radiated Fields (HIRF)
Recent advances in technology have given rise to the application in
aircraft designs of advanced electrical and electronic systems that
perform functions required for continued safe flight and landing. Due
to the use of sensitive solid state advanced components in analog and
digital electronics circuits, these advanced systems are readily
responsive to the transient effects of induced electrical current and
voltage caused by the HIRF. The HIRF can degrade electronic systems
performance by damaging components or upsetting system functions.
Furthermore, the HIRF environment has undergone a transformation
that was not foreseen when the current requirements were developed.
Higher energy levels are radiated from transmitters that are used for
radar, radio, and television. Also, the number of transmitters has
increased significantly. There is also uncertainty concerning the
effectiveness of airframe
[[Page 5540]]
shielding for HIRF. Furthermore, coupling to cockpit-installed
equipment through the cockpit window apertures is undefined.
The combined effect of the technological advances in airplane
design and the changing environment has resulted in an increased level
of vulnerability of electrical and electronic systems required for the
continued safe flight and landing of the airplane. Effective measures
against the effects of exposure to HIRF must be provided by the design
and installation of these systems. The accepted maximum energy levels
in which civilian airplane system installations must be capable of
operating safely are based on surveys and analysis of existing radio
frequency emitters. These special conditions require that the airplane
be evaluated under these energy levels for the protection of the
electronic system and its associated wiring harness. These external
threat levels, which are lower than previous required values, are
believed to represent the worst case to which an airplane would be
exposed in the operating environment.
These special conditions require qualification of systems that
perform critical functions, as installed in aircraft, to the defined
HIRF environment in paragraph 1 or, as an option to a fixed value using
laboratory tests, in paragraph 2, as follows:
(1) The applicant may demonstrate that the operation and
operational capability of the installed electrical and electronic
systems that perform critical functions are not adversely affected when
the aircraft is exposed to the HIRF environment defined below:
------------------------------------------------------------------------
Field strength (volts
per meter)
Frequency -------------------------
Peak Average
------------------------------------------------------------------------
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
2 GHz-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
------------------------------------------------------------------------
Note.--The field strengths are expressed in terms of peak root-mean-
square (rms) values.
or,
(2) The applicant may demonstrate by a system test and analysis
that the electrical and electronic systems that perform critical
functions can withstand a minimum threat of 100 volts per meter,
electrical field strength, from 10 kHz to 18 GHz. When using this test
to show compliance with the HIRF requirements, no credit is given for
signal attenuation due to installation.
A preliminary hazard analysis must be performed by the applicant,
for approval by the FAA, to identify either electrical or electronic
systems that perform critical functions. The term ``critical'' means
those functions whose failure would contribute to, or cause, a failure
condition that would prevent the continued safe flight and landing of
the airplane. The systems identified by the hazard analysis that
perform critical functions are candidates for the application of HIRF
requirements. A system may perform both critical and non-critical
functions. Primary electronic flight display systems, and their
associated components, perform critical functions such as attitude,
altitude, and airspeed indication. The HIRF requirements apply only to
critical functions.
Compliance with HIRF requirements may be demonstrated by tests,
analysis, models, similarity with existing systems, or any combination
of these. Service experience alone is not acceptable since normal
flight operations may not include an exposure to the HIRF environment.
Reliance on a system with similar design features for redundancy as a
means of protection against the effects of external HIRF is generally
insufficient since all elements of a redundant system are likely to be
exposed to the fields concurrently.
Applicability
As discussed above, these special conditions are applicable to
Cirrus Design Corporation Model SR22 airplane. Should Cirrus Design
Corporation apply at a later date for a type design change to modify
any other model on the same type certificate 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.
Conclusion
This action affects only certain novel or unusual design features
on one model of 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 these special conditions has been subjected to the
notice and comment period 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 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
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opportunities for comment described above.
List of Subjects in 14 CFR Part 23
Aircraft, Aviation safety, Signs and symbols.
Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and
21.101; and 14 CFR 11.38 and 11.19.
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 Cirrus Design Corporation SR22
airplane modified by Cirrus Design Corporation to add an EFIS.
1. Protection of Electrical and Electronic Systems from High
Intensity Radiated Fields (HIRF). Each system that performs critical
functions must be designed and installed to ensure that the operations,
and operational capabilities of these systems to perform critical
functions, are not adversely affected when the airplane is exposed to
high intensity radiated electromagnetic fields external to the
airplane.
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 Kansas City, Missouri, on January 24, 2003.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 03-2524 Filed 2-3-03; 8:45 am]
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