[Federal Register: February 26, 2007 (Volume 72, Number 37)]
[Rules and Regulations]
[Page 8261-8263]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr26fe07-2]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM369, Special Conditions No. 25-345-SC]
Special Conditions: Raytheon Aircraft Company Model BAe.125
Series 800A; High-Intensity Radiated Fields (HIRF)
AGENCY: Federal Aviation Administration (FAA), DOT.
[[Page 8262]]
ACTION: Final special conditions; request for comments.
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SUMMARY: These special conditions are issued for Raytheon Aircraft
Company Model BAe.125 Series 800A airplanes modified by Duncan Aviation
Inc. These modified airplanes will have novel or 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 electronic flight and
engine instrument systems. The applicable airworthiness regulations do
not contain adequate or appropriate safety standards for protecting
these systems from the effects of high-intensity radiated fields
(HIRF). These special conditions contain the additional safety
standards 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 February 12,
2007. We must receive your comments by March 28, 2007.
ADDRESSES: You must mail two copies of your comments to: Federal
Aviation Administration, Transport Airplane Directorate, Attention:
Rules Docket (ANM-113), Docket No. NM369, 1601 Lind Avenue SW., Renton,
Washington 98057-3356. You may deliver two copies to the Transport
Airplane Directorate at the address indicated above. You must mark your
comments: Docket No. NM369. You can inspect comments in the Rules
Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
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 98057-3356; telephone (425) 227-2799; facsimile (425) 227-
1320.
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 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, we invite interested persons to take part in this
rulemaking by sending 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. You may inspect the docket 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 by 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 October 27, 2006, Duncan Aviation, Inc., 15745 South Airport
Road, Battle Creek, Michigan 49015, applied for a supplemental type
certificate (STC) to modify Raytheon Aircraft Company Model BAe.125
Series 800A airplanes currently approved under Type Certificate No.
A3EU. The Model BAe.125 Series 800A airplanes are small transport
category airplanes. They are powered by two turbojet engines, with
maximum takeoff weight of 31,000 pounds as modified by Modification No.
253379A or 26,866 pounds as modified by Modification No. 25B047A. These
airplanes operate with 2-person crew and can seat up to 15 passengers.
The proposed modification is to install the Rockwell Collins Pro Line
21 Integrated Display Systems. The avionics/electronics and electrical
systems installed in this airplane have the potential to be vulnerable
to high-intensity radiated fields (HIRF) external to the airplane.
Type Certification Basis
Under 14 CFR 21.101, Duncan Aviation, Inc. must show the Raytheon
Aircraft Company Model BAe.125 Series 800A aircraft, as changed,
continue to meet the applicable provisions of the regulations
incorporated by reference in Type Certificate No. A3EU. They must also
continue to meet the applicable regulations in effect on the date of
application for the change. We commonly refer to the regulations
incorporated by reference in the type certificate as the ``original
type certification basis.'' The regulations incorporated by reference
in Type Certificate No. A3EU include Part 10 of the British Civil
Airworthiness Requirements. This certification is equivalent to Civil
Air Regulations (CAR) 4b dated December 1953, as amended by Amendment
4b-1 through Amendment 4b-11, exclusive of CAR 4b 350(e). It includes
Special Regulation SR 422B. In addition, the certification basis
includes certain later amendments to 14 CFR part 25 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 the Raytheon Aircraft Company Model
Bae.125, Series 800A airplanes, because of a novel or unusual design
feature, special conditions are prescribed under Sec. 21.16.
Besides the applicable airworthiness regulations and special
conditions, the Raytheon Aircraft Company Model BAe.125, Series 800A
airplanes, must comply with the fuel vent exhaust emission requirements
of 14 CFR part 34 and the noise certification requirements of 14 CFR
part 36.
We issue special conditions, as defined in 14 CFR 11.19, under
Sec. 11.38 and they become part of the type certification basis under
Sec. 21.101.
Special conditions are initially applicable to the model for which
they are issued. Should Duncan Aviation Inc., apply later for a
supplemental type certificate to modify any other model included on
Type Certificate No. A3EU to incorporate the same or similar novel or
unusual design feature, these special conditions would also apply to
the other model under Sec. 21.101.
Novel or Unusual Design Features
As noted earlier, the Raytheon Aircraft Company Model BAe.125
Series 800A aircraft, as modified by Duncan Aviation, Inc., will
incorporate the Rockwell Collins Pro Line 21 Integrated Display Systems
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
[[Page 8263]]
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 Raytheon Aircraft Company Model BAe.125
Series 800A airplanes modified by Duncan Aviation, 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 because of 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
------------------------------------------------------------------------
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
Raytheon Aircraft Company Model BAe.125 Series 800A airplanes modified
by Duncan Aviation, Inc. Should Duncan Aviation, Inc. apply later for a
supplemental type certificate to modify any other model included on
Type Certificate No. A3EU to incorporate the same or similar novel or
unusual design feature, these special conditions would apply to that
model as well.
Conclusion
This action affects only certain novel or unusual design features
on Raytheon Aircraft Company Model BAe.125 Series 800A airplanes as
modified by Duncan Aviation, 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.
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 send views that may
not have been sent 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 Raytheon Aircraft Company
Model BAe.125 Series 800A airplanes modified by Duncan Aviation, 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 February 12, 2007.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. E7-3231 Filed 2-23-07; 8:45 am]
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