[Federal Register Volume 68, Number 174 (Tuesday, September 9, 2003)]
[Rules and Regulations]
[Pages 53026-53028]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 03-22798]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM263, Special Conditions No. 25-245-SC]
Special Conditions: Sabreliner Model NA-265 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 for Sabreliner Model NA-
265 series airplanes, modified by Sabreliner Corporation. These
modified airplanes will have a novel or unusual design feature when
compared to the state of technology envisioned in the airworthiness
standards for transport category airplanes. The modification
incorporates the installation of Air Data systems that perform critical
functions by providing altitude, airspeed, or other critical data. 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 August 28,
2003. Comments must be received on or before October 9, 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. NM263, 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. NM263.
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 (425) 227-2145; facsimile (425) 227-1149.
SUPPLEMENTARY INFORMATION:
Comments Invited
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 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 based on the comments we receive.
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 May 21, 2003, Sabreliner Corporation, Pierre Laclede Center,
7733 Forsyth Boulevard, Suite 1500, St. Louis, Missouri 63105-1821,
applied for a supplemental type certificate (STC) to modify Sabreliner
Model NA-265 series airplanes. These airplanes are approved under Type
Certificate No. A2WE. The Model NA-265 series are small transport
category airplanes powered by two aft-mounted Pratt and Whitney Turbo
Wasp JT12A engines, with the exception of the Model NA-265-65, which
has two Air Research TFE731 turbofan engines, and the Model NA-265-80,
which has two GE Model CF700 turbofan engines. These airplanes operate
with a 2-pilot crew and can hold from 4 to 10 passengers depending on
the model within the series. The NA-265 series have a maximum takeoff
weight of 17,450 to 24,000 pounds, depending on the brake installation
and model within the series.
The modification incorporates the installation of Air Data systems
(combinations of Air Data Display Units, Air Computer, Air Data Sensor,
and/or Altimeter) that perform critical functions by providing
altitude, airspeed, or other critical data. These systems use
electronics to a far greater extent than the original instrument
systems, and may be more susceptible to electrical and magnetic
interference caused by high-intensity radiated fields (HIRF). The
disruption of these signals could result in loss of altitude, or
present misleading information to the pilot.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Sabreliner Corporation must
[[Page 53027]]
show that the Model NA-265 series airplanes, as changed, continue to
meet the applicable provisions of the regulations incorporated by
reference in Type Certificate No. A2WE, 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 certification
basis for the modified Sabreliner NA-265 series airplanes includes
Civil Air Regulation (CAR) 4b, dated December 31, 1953, as amended by
Amendments 4b-1 through 4b-9. In addition, under Sec. 21.101(b)(1),
Amendment 25-69, the following sections of 14 CFR part 25 apply to the
air data, altimeter, and display systems installed on the Sabreliner
NA-265 series airplanes: Sec. Sec. 25.1309(a), (c), (e), (f), and (g),
25.1321(a), (b), (d), and (e), 25.1331, and 25.1335 as amended by
Amendment 25-41; and Sec. 25.1316, as amended by Amendment 25-80. The
certification basis also includes other amendments and special
conditions, as noted in Type Certificate Data Sheet (TCDS) No. A2WE,
that are not relevant to these special conditions.
If the Administrator finds that the applicable airworthiness
regulations (that is, CAR 4b, as amended) do not contain adequate or
appropriate safety standards for the Sabreliner Model NA-265 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 Sabreliner Model NA-265 series airplanes must comply
with the fuel vent and exhaust emission requirement of SFAR 27 (now
codified as 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 Sabreliner Corporation apply at a later date
for a supplemental type certificate to modify any other model included
on Type Certificate No. A2WE to incorporate the same or similar novel
or unusual design features, 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 Sabreliner Model NA-265 series airplanes
modified by Sabreliner Corporation will incorporate the installation of
Air Data systems that perform critical functions. Because these
advanced systems use electronics to a far greater extent than the
original altimetry system, 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 of
part 25 do not contain adequate or appropriate safety standards for the
protection of this equipment from the adverse effects of HIRF.
Accordingly, these systems 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 Model NA-265 series airplanes, modified
by Sabreliner to include the new Air Data systems. These special
conditions require that the Air Data systems, 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, 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 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
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-100 MHz................................ 50 50
100 MHz-200 MHz............................... 100 100
200 MHz-400 MHz............................... 100 100
400 MHz-700 MHz............................... 700 50
700 MHz-1GHz.................................. 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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Note.--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
Sabreliner Model NA-265 series airplanes modified by Sabreliner. Should
Sabreliner Corporation apply at a later date for a supplemental type
certificate to modify any other model included on Type Certificate No.
A2WE 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 Sabreliner
[[Page 53028]]
Model NA-265 series airplanes modified by Sabreliner Corporation. 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.
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.
The authority citation for these special conditions 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 supplemental type certification basis for Sabreliner Model NA-265
series airplanes modified by Sabreliner Corporation.
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 August 28, 2003.
Kalene C. Yanamura,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 03-22798 Filed 9-8-03; 8:45 am]
BILLING CODE 4910-13-P