[Federal Register: January 21, 2005 (Volume 70, Number 13)]
[Rules and Regulations]
[Page 3140-3142]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr21ja05-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM300; Special Conditions No. 25-284-SC]
Special Conditions: Shadin Company, Inc., Cessna Aircraft Company
Model 501 and 551 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 for Cessna Aircraft
Company Model 501 and 551 series airplanes modified by Shadin Company,
Inc. These 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 two Shadin Company Air Data Computers
(ADC), Model ADC-6000. 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 January 12,
2005. Comments must be received on or before February 22, 2005.
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. NM300, 1601 Lind
Avenue SW., Renton, Washington 98055-4056; or delivered in duplicate to
the Transport Airplane Directorate at the above address. Comments must
be marked: Docket No. NM300.
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-
1149.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that notice and opportunity for prior public
comment is impracticable because these procedures would significantly
delay certification of the airplanes 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, we invite 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 we 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 in light of the comments received.
If you want the FAA to acknowledge receipt of your comments on
these special conditions, 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 March 3, 2004, Shadin Company, Inc., 6831 Oxford Street, St.
Louis Park, MN, 55426-4412, applied for a supplemental type certificate
(STC) to modify Cessna Aircraft Company Model 501 and 551 series
airplanes. These models are currently approved under Type Certificate
No. A27CE. These Cessna airplane models are small transport category
airplanes. The Cessna Model 501 is powered by two Pratt & Whitney
Aircraft of Canada, Ltd., JT15D-1A or JT15D-1B turbofans; and the
Cessna Model 551 is powered by two Pratt & Whitney Aircraft of Canada,
Ltd., JT15D-4 turbofans. The Cessna Model 501 has a maximum takeoff
weight of 11,850 pounds and the Cessna Model 551 has a maximum takeoff
weight of 12,500 pounds. The Cessna Model 501 operates with one to two-
pilot crews and holds up to 9 passengers and the Cessna Model 551
operates with one to two-pilot crews and holds up to 11 passengers. The
modification incorporates the installation of two Shadin ADC 6000
Reduced Vertical Separation Minimum (RVSM) capable systems, which will
allow for the removal of the existing encoding altimeters, air data
computer, and pneumatic altimeter. This system uses two ADC-6000s and
interfaces to existing BA-141 altimeters. These ADCs can be susceptible
to disruption to both command and response signals as a result of
electrical and magnetic interference. This disruption of signals could
result in the loss of all critical flight information displays and
annunciations or the presentation of misleading information to the
pilot. The avionics/electronics and electrical systems installed in
these airplanes have the potential to be vulnerable to high-intensity
radiated fields (HIRF) external to the airplanes.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Shadin Company, Inc. must
show that the Cessna Aircraft Company Model 501 and 551 series
airplanes, as changed, continue to meet the applicable provisions of
the regulations incorporated by reference in Type Certificate No.
A27CE, or the applicable regulations in effect on the date of
application for the change. The regulations incorporated by reference
in
[[Page 3141]]
the type certificate are commonly referred to as the ``original type
certification basis.'' The certification basis for the Cessna Model 501
series airplanes includes part 23 of 14 CFR effective February 1, 1965,
as amended by amendments 23-1 through 23-16 except as follows: Delete
Sec. Sec. 23.45 through 23.77, 23.831, 23.1091(c)(2), 23.1303,
23.1323, 23.1441 through 23.1449, 23.1581 through 23.1583(f), and
23.1583(h) through 23.1587; and add Sec. 23.1385 as amended through
amendment 23-20; and add part 25 of 14 CFR effective February 1, 1965,
as amended by amendments 25-1 through 25-17; Sec. Sec. 25.1195,
25.1199 and 25.1203 as amended by amendments 25-1 through 25-37;
Sec. Sec. 25.101 through 25.125, 25.831, 25.934, 25.1091(d)(2),
25.1197, 25.1201, 25.1303, 25.1305(a)(7), 25.1323, 25.1439 through
25.1453, 25.1581 through 25.1583(c)(3), and Sec. Sec. 25.1583(e)
through 25.1587.
The certification basis for the Cessna Model 551 series airplanes
includes part 23 of 14 CFR effective February 1, 1965, as amended by
amendments 23-1 through 23-16 except as follows: Delete Sec. Sec.
23.21 through 23.31, 23.45 through 23.77, 23.157, 23.171 through
23.177, 23.251, 23.345, 23.351, 23.361, 23.471 through 23.511, 23.571,
23.572, 23.629, 23.679, 23.723 through 23.737, 23.773, 23.775, 23.777,
23.783, 23.807, 23.831, 23.903(c), 23.1091(c)(2), 23.1301, 23.1303,
23.1307, 23.1309, 23.1321, 23.1323, 23.1325, 23.1385(c), 23.1435,
23.1441 through 23.1449, 23.1581 through 23.1583(f), 23.1583(i) through
23.1587; and add Sec. Sec. 23.1143(e) and 23.1385(c) as amended
through amendment 23-18 and 23.1301 and 23.1335 as amended through
amendment 23-20; and add from part 25 of 14 CFR effective February 1,
1965, as amended by amendments 25-1 through 25-17, Sec. Sec. 25.812,
25.863, 25.1195, 25.1199, 25.1203, 25.1309, and 25.1435; as amended by
amendment 25-1 through 25-37, Sec. Sec. 25.21 through 25.31, 25.101
through 25.125, 25.147(c)(e), 25.171 through 25.177, 25.251, 25.305(c),
25.345, 25.351, 25.361, 25.471 through 25.511, 25.571, 25.573, 25.629,
25.679, 25.721 through 25.737, 25.773, 25.775, 25.777, 25.783, 25.807,
25.831, 25.851, 25.903(b)(d), 25.934, 25.1091(d)(2), 25.1189(g)(h),
25.1197, 25.1201, 25.1303, 25.1305(a)(7), 25.1305(c)(4), 25.1307,
25.1321, 25.1323, 25.1325, 25.1439 through 25.1453, 25.1581 through
25.1583(c)(3), 25.1583(f) through 25.1587, and Sec. Sec. 25.901(c),
25.903(e)(3), and 25.1351(d) as amended through amendment 25-41.
In addition, the certification basis includes certain later amended
sections of the applicable part 25 regulations that are not relevant to
these special conditions.
If the Administrator finds that the applicable airworthiness
regulations (i.e., part 25, as amended) do not contain adequate or
appropriate safety standards for modified Cessna Aircraft Company Model
501 and 551 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 Cessna Model 501 and 551 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 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 issued. Should Shadin Company, Inc. apply at a later date for
a supplemental type certificate to modify any other model included on
Type Certificate No. A27CE to incorporate the same 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
As noted earlier, the Cessna Aircraft Company Model 501 and 551
series airplanes modified by Shadin Company, Inc. will incorporate a
new altitude display system that will perform critical functions. These
systems may be vulnerable to high-intensity radiated fields external to
the airplane. The current airworthiness standards of part 25 do not
contain adequate or appropriate safety standards for the protection of
this equipment from the adverse effects of HIRF. Accordingly, this
system is considered to be a novel or unusual design feature.
Discussion
There is no specific regulation that addresses protection
requirements for electronic and electrical 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 501 and 551 series airplanes
modified by Shadin Company, 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 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 is shown with either HIRF protection
special condition 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
100kHz-500 kHz.................................. 50 50
500 kHz-2 MHz................................... 50 50
2 MHz-30 MHz.................................... 100 100
30 MHz-70 MHz................................... 50 50
70 MHz-100MHz................................... 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-2GHz...................................... 2000 200
2 GHz-4 GHz..................................... 3000 200
4 GHz-6 GHz..................................... 3000 200
6 GHz-8 GHz..................................... 1000 200
[[Page 3142]]
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 the
Cessna Aircraft Company Model 501 and 551 series airplanes. Should
Shadin Company, Inc. apply at a later date for a supplemental type
certificate to modify any other model included on Type Certificate No.
A27CEU to incorporate the same or similar 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 Cessna Model 501 and 551 series airplanes modified by Shadin
Company, 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 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. 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.
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 the Cessna Aircraft
Company Model 501 and 551 series airplanes modified by Shadin Company,
Inc.
1. Protection from Unwanted Effects of High-Intensity Radiated
Fields (HIRF). Each electronic and electrical 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 January 12, 2005.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 05-1156 Filed 1-19-05; 8:45 am]
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