[Federal Register Volume 62, Number 145 (Tuesday, July 29, 1997)]
[Rules and Regulations]
[Pages 40427-40429]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-19858]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM-143; Special Conditions No. 25-ANM-130]
Special Conditions: International Aviation Services, Ltd.; Boeing
Model 747-SP 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 Boeing Model 747-SP
airplanes modified by International Aviation Services, Ltd. 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. 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 July 17, 1997.
Comments must be received on or before August 28, 1997.
ADDRESSES: Comments on these special conditions may be mailed in
duplicate to: Federal Aviation Administration, Office of the Assistant
Chief Counsel, Attn: Rules Docket (ANM-7), Docket No. NM-143, 1601 Lind
Avenue SW., Renton, Washington, 98055-4056; or delivered in duplicate
to the Office of the Assistant Chief Counsel at the above address.
Comments must be marked: Docket No. NM-143. Comments may be inspected
in the Rules Docket weekdays, except Federal holidays, between 7:30
a.m. and 4:00 p.m.
FOR FURTHER INFORMATION CONTACT: Tom Groves, FAA, Standardization
Branch, ANM-113, 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 regulatory docket and
special condition 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. NM-143.'' The postcard will
be date stamped and returned to the commenter.
Background
On August 8, 1996, International Aviation Services, Ltd. applied
for a supplemental type certificate (STC) to modify Boeing Model 747-SP
airplanes
[[Page 40428]]
listed on Type Certificate A20WE. The modification includes the
installation of a 5-tube electronic flight instrument system (EFIS)
that will replace the existing electro-mechanical horizontal situation
indicator (HSI) and attitude director indicator (ADI). These systems,
which display flight critical information, are vulnerable to high-
intensity radiated fields (HIRF) external to the airplane.
Type Certification Basis
Under the provisions of 14 CFR Sec. 21.101, International Aviation
Services, Ltd. must show that the Boeing Model 747-SP, as changed,
continues to meet the applicable provisions of the regulations
incorporated by reference in Type Certificate A20WE, 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 Model 747-SP includes 14 CFR part
25, as amended by Amendments 25-1 through 25-8 and certain later
amendments, special conditions, exemptions, and optional requirements
listed in the type certificate data sheet that are not relevant to
these special conditions. In addition, the certification basis for the
modifications, and for areas affected by the modifications, will be
amended to include the following sections:
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Section Amendment Title
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25.779(a)..................... 25-72 Motion and effect of cockpit
controls.
25.1303....................... 25-38 Flight and navigation
instruments.
25.1307....................... 25-72 Miscellaneous equipment.
25.1309....................... 25-41 Equipment, systems, and
installations.
25.1316....................... 25-80 System lightning protection.
25.1321....................... 25-41 Arrangement and visibility.
25.1322....................... 25-38 Warning, caution, and
advisory lights.
25.1329....................... 25-46 Automatic pilot system.
25.1331....................... 25-41 Instruments using a power
supply.
25.1333....................... 25-41 Instrument systems.
25.1335....................... 25-41 Flight director systems.
25.1381....................... 25-72 Instrument lights.
25.1501....................... 25-42 General.
25.1529....................... 25-54 Instructions for Continued
Airworthiness.
25.1581....................... 25-72 General.
25.1583....................... 25-72 Operating limitations.
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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 Boeing Model 747-SP airplane
because of novel or unusual design features, special conditions are
prescribed under the provisions of Sec. 21.16 to establish a level of
safety equivalent to that established in the regulations.
Special conditions, as appropriate, are issued in accordance with
14 CFR Sec. 11.49 after public notice, as required by Secs. 11.28 and
11.29, and become part of the type certification basis in accordance
with Sec. 21.101(b)(2).
Special conditions are initially applicable to the model for which
they are issued. Should International Aviation Services, Ltd. apply at
a later date for an STC to modify any other model already included on
the same type certificate to incorporate the same novel or unusual
design feature, the special conditions would also apply to the other
model under the provisions of Sec. 21.101(a)(1).
Novel or Unusual Design Features
The Boeing Model 747-SP will incorporate a new electronic flight
instrument system 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 regulations incorporated by reference, special
conditions are needed for the Boeing Model 747-SP, 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,
couples 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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Peak (V/ Average
Frequency M) (V/M)
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10 KHz-100 KHz........................................ 50 50
100 KHz-500 KHz....................................... 60 60
500 KHz-2 MHz......................................... 70 70
2 MHz-30 MHz.......................................... 200 200
30 MHz-100 MHz........................................ 30 30
100 MHz-200 MHz....................................... 150 33
200 MHz-400 MHz....................................... 70 70
400 MHz-700 MHz....................................... 4,020 935
700 MHz-1 GHz......................................... 1,700 170
1 GHz-2 GHz........................................... 5,000 990
2 GHz-4 GHz........................................... 6,680 840
4 HGz-6 GHz........................................... 6,850 310
6 GHz-8 GHz........................................... 3,600 670
8 GHz-12 GHz.......................................... 3,500 1,270
12 GHz-18 GHz......................................... 3,500 360
18 GHz-40 GHz......................................... 2,100 750
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Applicability
As discussed above, these special conditions are applicable to
Boeing Model 747-SP airplanes modified by International Aviation
Services, Ltd. Should International Aviation Services, Ltd. apply at a
later date for a supplemental type certificate to modify any other
model included on Type Certificate A20WE to incorporate the same novel
or unusual design feature, the special conditions would apply to that
model as well under the provisions of Sec. 21.101(a)(1).
[[Page 40429]]
Conclusion
This action affects only certain design features on Boeing Model
747-SP airplanes modified by International Aviation Services, Ltd. 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 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 Boeing Model 747-SP airplanes modified
by International Aviation Services, Ltd.
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.
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 July 17, 1997.
Gary L. Killion,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service.
[FR Doc. 97-19858 Filed 7-28-97; 8:45 am]
BILLING CODE 4910-13-M
