[Federal Register: October 22, 2003 (Volume 68, Number 204)]
[Rules and Regulations]
[Page 60281-60283]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr22oc03-1]
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Rules and Regulations
Federal Register
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[[Page 60281]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM268, Special Conditions No. 25-252-SC]
Special Conditions: Cessna Aircraft Company Cessna Model 500
Airplanes; High Intensity Radiated Fields (HIRF)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions; request for comments.
-----------------------------------------------------------------------
SUMMARY: These special conditions are issued for Cessna Aircraft
Company Cessna Model 500 airplanes modified by Honeywell International,
Inc. These modified airplanes will have novel and unusual design
features when compared to the state of technology envisioned in the
airworthiness standards for transport category airplanes. The
modification incorporates the installation of dual Honeywell RVSM
(reduced vertical separation minimum)-capable AM-250 electronic
barometric altimeters. 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 October 14,
2003. Comments must be received on or before November 21, 2003.
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. NM268, 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. NM268.
FOR FURTHER INFORMATION CONTACT: Greg Dunn, FAA, Airplane and Flight
Crew Interface Branch, ANM-111, Transport Airplane Directorate,
Aircraft Certification Service, 1601 Lind Avenue SW., Renton,
Washington, 98055-4056; telephone (425) 227-2799; facsimile (425) 227-
1320.
SUPPLEMENTARY INFORMATION: The FAA has determined that notice and
opportunity for prior public comment are impracticable because these
procedures would significantly delay certification of the airplane 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; 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 were 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 this
proposal, 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 June 12, 2003, Honeywell International, Inc., 23500 W. 105th
St., Olathe, KS 66061, applied for a supplemental type certificate
(STC) to modify Cessna (Citation) Model 500 airplanes. This model is
currently approved under Type Certificate No. A22CE. The Cessna Model
500 airplanes are executive type transports that have two aft mounted
turbine engines, a minimum passenger load of 9 passengers, and a
maximum operating speed of 260 to 287 knots, depending on altitude. The
modification, under one supplemental type certificate (STC) project,
incorporates the installation of dual Honeywell RVSM-capable AM-250
electronic barometric altimeters.
The dual Honeywell AM-250 barometric altimeters provide the
aircraft baro-corrected altitude information, also corrected for static
source error (SSE), which enables the aircraft to be capable of RVSM
operations. The dual AM-250 barometric altimeters replace the existing
pilot and copilot pneumatic altimeters. Since the AM-250 altimeters use
electronics to transmit altimeter data to the pilots, as well as to
other equipment, they may be susceptible to electrical and magnetic
interference caused by high-intensity radiated fields (HIRF). This
disruption of signals could result in misleading altimeter information
to the pilots or loss of altimeter information.
Type of Certification Basis
Under the provisions of 14 CFR 21.101, Honeywell International,
Inc. must show that the Cessna Model 500 airplanes, as changed,
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 ``the original type
certification basis.'' The certification basis for the modified Cessna
Model 500 airplanes includes Part 25 of the Federal Aviation
Regulations effective February 1, 1965, as amended by Amendments 25-1
through 25-17. Other applicable amendments, Federal aviation
regulations, and special conditions are
[[Page 60282]]
also noted in Type Certificate Data Sheet (TCDS) A22CE.
If the Administrator finds that the applicable airworthiness
regulations (that is, 14 CFR part 25, as amended) do not contain
adequate or appropriate safety standards for the Cessna Model 500
airplanes because of novel or unusual design features, special
conditions are prescribed under the provisions of Sec. 21.16.
In addition to the applicable airworthiness regulations and special
conditions, the Cessna Model 500 airplanes must comply with the fuel
vent and exhaust emission requirement of 14 CFR part 34 and the noise
certification requirement of part 36.
Special conditions, as defined in 14 CFR 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 issues. Should Honeywell International, Inc. apply at a later
date 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 features, these special conditions would also
apply to the other model under the provisions of 14 CFR 21.101.
Novel or Unusual Design Features
The Cessna Model 500 airplanes will incorporate, under one
supplemental type certificate (STC) project, the installation of dual
Honeywell AM-250 barometric altimeters. Because these altimeters use
electronics to a far greater extent than the original pneumatic or
servo altimeters, they may be more susceptible to electrical and
magnetic interference caused by high-intensity radiated fields (HIRF)
external to the airplane. The current airworthiness standards (14 CFR
part 25) do not contain adequate or appropriate safety standards that
address protecting this equipment from the adverse effects of HIRF.
Accordingly, these instruments are 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 Cessna Model 500 airplanes modified to
include the new altimeters. These special conditions will require that
the new Honeywell AM-250 barometric altimeters, which 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/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 in accordance 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
indicated in the table below for the frequency ranges indicated. Both
peak and average field strength components from the table below are to
be demonstrated.
------------------------------------------------------------------------
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
------------------------------------------------------------------------
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
Cessna Model 500 airplanes modified by Honeywell International, Inc. to
include dual Honeywell AM-250 barometric altimeters. should Honeywell
International, Inc. apply at a later date for a supplemental type
certificate to modify any other model already included on Type
Certificate A22CE to incorporate; the same novel or unusual design
features, these special conditions would apply to that model as well
under the provisions of 14 CFR 21.101.
Conclusion
This action affects only certain design features on Cessna Model
500 airplanes modified by Honeywell International, 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 the special conditions for this airplane has been
subjected to 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 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.
[[Page 60283]]
0
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701, 44702, 44704.
The Special Conditions
0
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 Cessna model 500
airplanes modified by Honeywell International, 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 October 14, 2003.
Neil D. Schalekamp,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 03-26559 Filed 10-21-03; 8:45 am]
BILLING CODE 4910-13-M