[Federal Register Volume 64, Number 92 (Thursday, May 13, 1999)]
[Rules and Regulations]
[Pages 25800-25802]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-12143]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM154, Special Conditions No. 25-99-273-SC]
Special Conditions: Dornier Model 328-300 Airplane; 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 the Dornier Model 328-
300 airplane. This airplane will have novel and unusual design features
when compared to the state of technology envisioned in the
airworthiness standards for transport category airplanes. 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 April 15,
1999. Comments must be received on or before June 28, 1999.
ADDRESSES: Comments on these special conditions may be mailed in
duplicate to: Federal Aviation Administration, Office of the Regional
Counsel, Attn: Rules Docket (ANM-7), Docket No. NM154, 1601 Lind Avenue
SW., Renton, Washington, 98055-4056; or delivered in duplicate to the
Office of the Regional Counsel at the above address. Comments must be
marked: Docket No. NM154. 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: Tom Groves, FAA, International Branch,
ANM-116, Transport Airplane Directorate, Aircraft Certification
Service, 1601 Lind Avenue SW., Renton, Washington, 98055-4056;
telephone (425) 227-1503; facsimile (425) 227-1149.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA has determined that good cause exists for making these
special conditions effective upon issuance; however, interested persons
are invited to submit such written data, views, or arguments as they
may desire. Communications should identify the docket and special
conditions 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. These
special conditions may be changed in light of the comments received.
All comments submitted 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. Persons wishing the FAA to acknowledge receipt of their
comments submitted in response to this request must submit with those
comments a self-addressed, stamped postcard on which the following
statement is made: ``Comments to Docket No. NM154.'' The postcard will
be date stamped and returned to the commenter.
Background
On November 14, 1996, the Luftfahrt-Bundesamt (LBA) applied on
behalf of Dornier Luftfahrt GmbH for an amendment to U.S. Type
Certificate No. A45NM to include the new Dornier Model 328-300. The
Model 328-300, which is a modification of the Dornier Model 328-100
approved under Type Certificate No. A45NM, will be a 32-34 passenger
airplane with a pressurized cabin and a maximum takeoff weight of
33,510 pounds (15200 kg). The Model 328-300 is of a high-wing
configuration, with twin turbofan engines mounted underneath the wings,
and a horizontal tail mounted at the top of the vertical fin. The FAA
subsequently determined that this airplane would require a new type
certificate because the type of propulsion on this airplane is being
changed from turboprop to turbofan.
The Dornier Model 328-300 incorporates an electronic flight
instrument system (EFIS) for display of critical flight parameters
(altitude, airspeed, and attitude) to the crew. These displays can be
susceptible to disruption to both command/response signals as a result
of electrical and magnetic interference. This disruption of signals
could result in loss of all critical flight displays and annunciations
or present misleading information to the pilot.
[[Page 25801]]
Type Certification Basis
Under the provisions of 14 CFR 21.17, Dornier Luftfahrt GmbH must
show that the Model 328-300 airplane meets the applicable provisions of
part 25 as amended by Amendments 1 through 87 thereto.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 25, as amended) do not contain adequate
or appropriate safety standards for the Dornier Model 328-300 airplane
because of novel or unusual design features, special conditions are
prescribed under the provisions of Sec. 21.16.
Special conditions, as appropriate, are issued in accordance with
14 CFR 11.49, as required by Secs. 11.28 and 11.29, and become part of
the type certification basis in accordance with Sec. 21.17(a)(2).
Special conditions are initially applicable to the model for which
they are issued. Should the type certificate for that model be amended
later to include any other model that incorporates the same novel or
unusual design feature, these special conditions would also apply to
the other model under the provisions of Sec. 21.101(a)(1).
Novel or Unusual Design Features
The Dornier 328-300 will incorporate an electronic flight
instrument system (EFIS) that performs critical functions. This system
may be vulnerable to HIRF external to the airplane.
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 electrical and electronic 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 applicable regulations, special conditions are needed
for the Dornier 328-300, which require that new electrical and
electronic systems, such as the EFIS, 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, plus the advent of space and satellite communications,
coupled with electronic command and control of the airplane, the
immunity of critical digital avionics 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 paragraphs 1, or 2 below:
1. A minimum threat of 100 volts per meter peak 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 following field
strengths for the frequency ranges indicated.
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Field Strength (volts per meter)
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US UK/European Consolidated
Frequency -----------------------------------------------------------------------------------------------
Peak Average Peak Average Peak Average
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10 kHz-100 kHz.......................................... 30 30 50 50 50 50
100 kHz-500 kHz......................................... 40 30 60 60 60 60
500 kHz-2 MHz........................................... 30 30 70 70 70 70
2 MHz-30 MHz............................................ 190 190 200 200 200 200
30 MHz-70 MHz........................................... 20 20 30 30 30 30
70 MHz-100 MHz.......................................... 20 20 30 30 30 30
100 MHz-200 MHz......................................... 30 30 150 30 150 30
200 MHz-400 MHz......................................... 30 30 70 70 70 70
400 MHz-700 MHz......................................... 80 80 700 40 700 80
700 MHz-1 GHz........................................... 690 240 1700 80 1700 240
1 GHz-2 GHz............................................. 970 70 5000 360 5000 360
2 GHz-4 GHz............................................. 1570 350 4500 360 4500 360
4 GHz-6 GHz............................................. 7200 300 5200 300 7200 300
6 GHz-8 GHz............................................. 130 80 2000 330 2000 330
8 GHz-12 GHz............................................ 2100 80 3500 270 3500 270
12 GHz-18 GHz........................................... 500 330 3500 180 3500 330
18 GHz-40 GHz........................................... 780 20 NA NA 780 20
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The field strengths are expressed in terms of peak root-mean-square (rms) values.
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Applicability
As discussed above, these special conditions are applicable to
Dornier 328-300 Model airplane. Should Dornier Luftfahrt GmbH apply any
other model included on the same type certificate to incorporate the
same noval or unusual design feature, these special conditions would
apply to that model as well under the provisions of Sec. 21.101(a)(1).
Conclusion
This action affects only Dornier Model 328-300 airplanes. 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 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
[[Page 25802]]
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 immediately. Therefore, these special
conditions are being made effective 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 type certification basis for Dornier Model 328-300 airplane.
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 external to the airplane.
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 April 15, 1999.
John J. Hickey,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 99-12143 Filed 5-12-99; 8:45 am]
BILLING CODE 4910-13-U
