[Federal Register: August 24, 2006 (Volume 71, Number 164)]
[Rules and Regulations]
[Page 49987-49989]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24au06-4]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE258; Special Conditions No. 23-198-SC]
Special Conditions: Avcon Industries, Inc.; Learjet Model 23
Series Airplanes; 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 Avcon Industries, Inc.,
for the Learjet Model 23 series airplanes modified by Avcon Industries,
Inc. This airplane as modified by Avcon Industries, Inc., will have a
novel or unusual design feature associated with the installation of a
new Reduced Vertical Separation Minimum (RVSM) air data system. 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 established by the existing airworthiness standards.
DATES: The effective date of these special conditions is August 17,
2006. Comments must be received on or before September 25, 2006.
ADDRESSES: Comments on these special conditions may be mailed in
duplicate to: Federal Aviation Administration, Regional Counsel, ACE-7,
Attention: Rules Docket CE258, 901 Locust, Room 506, Kansas City,
Missouri 64106 or delivered in duplicate to the Regional Counsel at the
above address. Comments must be marked: CE258. 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: Ervin Dvorak, Federal Aviation
Administration, Aircraft Certification Service, Small Airplane
Directorate, ACE-111, 901 Locust, Room 301, Kansas City, Missouri
64106; 816-329-4123; fax 816-329-4090.
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 approval design 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 on 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 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. 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 CE258.'' The postcard will be date stamped and returned
to the commenter.
Background
On June 26, 2006, Avcon Industries, Inc.; P.O. Box 748; Newton,
Kansas 67114, applied for a supplemental type certificate (STC) to
modify Learjet Model 23 series airplanes currently approved under Type
Certificate (TC) No. A5CE. The Learjet 23 series airplanes are normal
category airplanes powered by two turbojet engines, with a maximum
takeoff weight of 12,500 pounds. These airplanes operate with a 2-
person crew and can seat up to 8 passengers. The proposed modification
is the installation of an Innovative Solutions & Support Air Data
Display Units and Analog Interface Unit. The avionics/electronics and
electrical systems installed in this airplane have the potential to be
vulnerable to HIRF external to the airplane.
Type Certification Basis
Under the provisions of Sec. 21.101, Avcon Industries, Inc., must
show that the Learjet Model 23 series airplanes, as changed, continue
to meet the applicable provisions of the regulations incorporated by
reference in Type Certificate No. A5CE, 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 the Type Certificate No. A5CE for the
Learjet Model 23 series airplanes includes Civil Air Regulations (CAR),
part 3, effective May 15, 1956, as amended by Amendments 3-1 through 3-
8, plus special conditions set forth in FAA letter to Learjet, dated
November 12, 1963, and Amendment No. 1, dated July 31, 1964, and No. 2,
dated March 14, 1966, and Exception No. 352 from compliance with CAR
3.74(a)(2) and (3) for ground operation at a maximum weight of 12,750
pounds.
If the Administrator finds that the applicable airworthiness
regulations (i.e., part 23, as amended) do not
[[Page 49988]]
contain adequate or appropriate safety standards for the Learjet Model
23 series airplanes because of a novel or unusual design feature,
special conditions are prescribed under the provisions of Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the Learjet Model 23 series airplanes 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 appropriate, as defined in Sec. 11.19, are
issued in accordance with Sec. 11.38, and become part of the type
certification basis in accordance with Sec. 21.101.
Special conditions are initially applicable to the model for which
they are issued. Should Avcon Industries, Inc., apply for a
supplemental type certificate to modify any other model included on TC
No. A5CE to incorporate the same or a 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 Learjet Model 23 series airplanes, as modified by Avcon
Industries, Inc., will incorporate an Innovative Solutions & Support
Air Data Display Units and Analog Interface Unit. The Innovative
Solutions & Support Air Data Display Units and Analog Interface Unit
perform critical functions. These systems may be vulnerable to HIRF
external to the airplane. The current airworthiness standards of part
23 do not contain adequate or appropriate safety standards for the
protection of this equipment from the adverse effects of HIRF.
Therefore, we consider this system 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 Learjet Model 23 series airplanes as
modified by Avcon Industries, Inc. 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 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
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
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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
Learjet Model 23 series airplanes modified by Avcon Industries, Inc.
Should Avcon Industries, Inc., apply later for an STC to modify any
other model included on TC No. A5CE to incorporate the same novel or
unusual design feature, these 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 the Learjet 23 series airplanes modified by Avcon Industries, Inc.
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 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 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 23
Aircraft, Aviation safety, Signs and symbols.
Citation
The authority citation for these special conditions is as follows:
[[Page 49989]]
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 the Learjet Model 23 series airplanes
modified by Avcon Industries, 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 Kansas City, Missouri on August 17, 2006.
David R. Showers,
Acting Manager, Small Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E6-13995 Filed 8-23-06; 8:45 am]
BILLING CODE 4910-13-P