[Federal Register Volume 65, Number 229 (Tuesday, November 28, 2000)]
[Rules and Regulations]
[Pages 70773-70775]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-30303]
[[Page 70773]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 29
[Docket No. SW007; Special Condition No. 29-007-SC]
Special Conditions: Eurocopter France Model EC-155 Helicopters,
High-Intensity Radiated Fields
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special condition; request for comments.
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SUMMARY: This special condition is issued for Eurocopter France
(Eurocopter) Model EC-155 helicopters. These helicopters will have
novel or unusual design features associated with the installation of
electronic systems that perform critical functions. The applicable
airworthiness regulations do not contain adequate or appropriate safety
standards to protect systems that perform critical control functions or
provide critical displays from the effects of high-intensity radiated
fields (HIRF). This special condition contains the additional safety
standards that the Administrator considers necessary to ensure that
critical functions of systems will be maintained when exposed to HIRF.
DATES: The effective date of this special condition is October 31,
2000. Comments must be received on or before January 12, 2001.
ADDRESSES: Comments on this special condition may be mailed in
duplicate to: Federal Aviation Administration, Office of the Regional
Counsel, Attention: Rules Docket No. SW007, Fort Worth, Texas 76193-
0007, or delivered in duplicate to the Office of the Regional Counsel
at 2601 Meacham Blvd., Fort Worth, Texas 76137. Comments must be
marked: Rules Docket No. SW007. Comments may be inspected in the Rules
Docket weekdays, except Federal holidays, between 8:30 a.m. and 4:00
p.m.
FOR FURTHER INFORMATION CONTACT: Jorge Castillo, FAA, Rotorcraft
Directorate, Rotorcraft Standards, Fort Worth, Texas 76193-0110;
telephone (817) 222-5127, fax (817) 222-5961.
SUPPLEMENTARY INFORMATION: The FAA has determined that notice and
opportunity for prior public comment hereon are impracticable because
these procedures would significantly delay issuance of the approval
design and thus delivery of the affected aircraft. In addition, notice
and opportunity for prior public comment are unnecessary since the
substance of this special condition 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
this special condition effective upon issuance.
Comments Invited
Interested persons are invited to submit such written data, views,
or arguments as they may desire. Communications should identify the
regulatory docket or 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. The
special condition may be changed in light of the comments received. All
comments received will be available in the Rules Docket for examination
by interested persons. A report summarizing each substantive public
contact with FAA personnel concerning this rulemaking will be filed in
the docket. Commenters wishing the FAA to acknowledge receipt of their
comments submitted in response to this special condition must include a
self-addressed, stamped postcard on which the following statement is
made: ``Comments to Rules Docket No. SW007.'' The postcard will be date
stamped and returned to the commenter.
Background
On September 1, 1998, Eurocopter submitted an application for Type
Validation of Model EC-155 Transport Category helicopters through the
Direction Generale de l'Aviation Civile (DGAC), which is the
airworthiness authority of France, and the FAA Brussels Aircraft
Certification Office (ACO). Model EC-155 helicopters are a derivative
of Model AS365N3 helicopters that achieved FAA Type Certification on
November 8, 1998. The main design differences between Model EC-155 and
Model AS365N3 helicopters include the following: a gross weight
increase from 4250 kg to 4800 kg; enlarged fuselage structure; a new 5-
blade speriflex main rotor and composite fenestron blades; and a new
avionics instrumentation package that includes a 3-axis digital
Automatic Flight Control System (AFCS) and electronic displays.
Type Certification Basis
Under the provisions of 14 CFR 21.17, Eurocopter must show that
Model EC-155 helicopters meet the applicable provisions of the
regulations as listed below:
--14 CFR 21.29.
--14 CFR part 29, Amendment 29-1 through Amendment 29-40 with the
following exceptions:
--Excluding Amendment 29-38.
--Excluding 14 CFR 29.952, introduced at Amendment 29-35.
--Excluding 14 CFR 29.562, introduced at Amendment 29-29.
--Excluding 14 CFR 29.631, introduced at Amendment 29-40.
--Section 29.561(a), (b), and (d) at Amendment 29-1.
--Section 29.561(c) at Amendment 29-29.
--Section 29.571 at Amendment 29-20.
--Section 29.785 at Amendment 29-24.
--Section's 29.963, 29.973, and 29.975 at Amendment 29-26.
--Section 29.1305(a)(4)(i) at Amendment 29-16.
--14 CFR part 36, Appendix H through the latest amendment in effect
at the time that the noise tests are conducted.
--Any Special conditions, Exemptions, and Equivalent Safety
Findings deemed necessary.
In addition, the certification basis includes certain special
conditions and equivalent safety findings that are not relevant to this
special condition.
If the Administrator finds that the applicable airworthiness
regulations do not contain adequate or appropriate safety standards for
these helicopters 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, Eurocopter Model EC-155 helicopters must comply with the
noise certification requirements of 14 CFR part 36; and the FAA must
issue a finding of regulatory adequacy pursuant to section 611 of
Public Law 92-574, the ``Noise Control Act of 1972.''
Special conditions, as appropriate, are issued in accordance with
Sec. 11.49, as required by Secs. 11.28 and 11.29(b), 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, the special conditions would also apply to the
other model under the provisions of Sec. 21.101(a)(1).
Novel or Unusual Design Features
Eurocopter Model EC-155 helicopters will incorporate the following
novel or unusual design features: electrical,
[[Page 70774]]
electronic, or a combination of electrical electronic (electrical/
electronic) systems that will perform critical control functions or
display critical information, such as electronic flight instruments
that display critical information required for the continued safe
flight and landing of the helicopter during operation in Instrument
Meteorological Conditions (IMC); and Full Authority Digital Engine
Control (FADEC) that will perform engine control functions that are
critical to the continued safe flight and landing of the helicopter
during Visual Flight Rules (VFR) and Instrument Flight Rules (IFR)
operations.
Discussion
Eurocopter Model EC-155 helicopters, at the time of application,
were identified as incorporating one and possibly more electrical/
electronic systems, such as electronic flight instruments and FADEC.
After the design is finalized, Eurocopter will provide the FAA with a
preliminary hazard analysis that will identify any other critical
functions required for safe flight and landing that are performed by
the electrical/electronic systems.
Recent advances in technology have given rise to the application in
aircraft designs of advanced electrical/electronic systems that perform
critical control functions or provide critical displays. These advanced
systems respond to the transient effects of induced electrical current
and voltage caused by HIRF incident on the external surface of the
helicopter. These induced transient currents and voltages can degrade
the performance of the electrical/electronic systems by damaging the
components or by upsetting the systems' functions.
Furthermore, the electromagnetic environment has undergone a
transformation not envisioned by the current application of
Sec. 29.1309(a). Higher energy levels radiate from operational
transmitters currently used for radar, radio, and television. Also, the
number of transmitters has increased significantly.
Existing aircraft certification requirements are inappropriate in
view of these technological advances. In addition, the FAA has received
reports of some significant safety incidents and accidents involving
military aircraft equipped with advanced electrical/electronic systems
when they were exposed to electromagnetic radiation.
The combined effects of the technological advances in helicopter
design and the changing environment have resulted in an increased level
of vulnerability of the electrical/electronic systems required for the
continued safe flight and landing of the helicopter. Effective measures
to protect these helicopters against the adverse effects of exposure to
HIRF will be provided by the design and installation of these systems.
The following primary factors contributed to the current conditions:
(1) Increased use of sensitive electronics that perform critical
functions; (2) reduced electromagnetic shielding afforded helicopter
systems by advanced technology airframe materials; (3) adverse service
experience of military aircraft using these technologies; and (4) an
increase in the number and power of radio frequency emitters and the
expected increase in the future.
The FAA recognizes the need for aircraft certification standards to
keep pace with the developments in technology and environment and, in
1986, initiated a high priority program to: (1) Determine and define
electromagnetic energy levels; (2) develop and describe guidance
material for design, test, and analysis; and (3) prescribe and
promulgate regulatory standards.
The FAA participated with industry and airworthiness authorities of
other countries to develop internationally recognized standards for
certification.
The FAA and airworthiness authorities of other countries have
identified two levels of the HIRF environment that a helicopter could
be exposed to, one environment for VFR operations and a different
environment for IFR operations. While the HIRF rulemaking requirements
are being finalized, the FAA is adopting a special condition for the
certification of aircraft that employ electrical/electronic systems
that perform critical control functions or provide critical displays.
The accepted maximum energy levels that civilian helicopter system
installations must withstand for safe operation are based on surveys
and analysis of existing radio frequency emitters. This special
condition will require the helicopters' electrical/electronic systems
and associated wiring to be protected from these energy levels. These
external threat levels are believed to represent the exposure for a
helicopter operating under VFR or IFR.
Compliance with HIRF requirements will be demonstrated by tests,
analysis, models, similarity with existing systems, or a combination of
these methods. Service experience alone will not be acceptable since
such experience in normal flight operations may not include an exposure
to HIRF. Reliance on a system with similar design features for
redundancy, as a means of protection against the effects of external
HIRF, is generally insufficient because all elements of a redundant
system are likely to be concurrently exposed to the radiated fields.
This special condition will require the aircraft-installed systems
that perform critical control functions or provide critical displays to
meet certain standards based on either a defined HIRF environment or a
fixed value using laboratory tests. Control system failures and
malfunctions can more directly and abruptly contribute to a
catastrophic event than display system failures and malfunctions.
Therefore, it is considered appropriate to require more rigorous HIRF
verification methods for critical control systems than for critical
display systems.
The applicant may demonstrate that the operation and operational
capabilities of the installed electrical/electronic systems that
perform critical functions are not adversely affected when the aircraft
is exposed to the defined HIRF test environment. The FAA has determined
that the test environment defined in Table 1 is acceptable for critical
control functions in helicopters. The test environment defined in Table
2 is acceptable for critical display systems in helicopters.
The applicant may also demonstrate by a laboratory test that the
electrical/electronic systems that perform critical control functions
or provide critical displays can withstand a peak electromagnetic field
strength in a frequency range of 10 kHz to 18 GHz. If a laboratory test
is used to show compliance with the defined HIRF environment, no credit
will be given for signal attenuation due to installation. A level of
100 volts per meter (v/m) is appropriate for critical display systems.
A level of 200 v/m is appropriate for critical control functions.
Laboratory test levels are defined according to RTCA/DO-160D Section 20
Category W (100 v/m and 150 mA) and Category Y (200 v/m and 300 mA). As
stated in DO-160D Section 20, the test levels are defined as the peak
of the root means squared (rms) envelope. As a minimum, the modulations
required for RTCA/DO-160D Section 20 Categories W and Y will be used.
Other modulations should be selected as the signal most likely to
disrupt the operation of the system under test, based on its design
characteristics. For example, flight control systems may be susceptible
to 3 Hz square wave modulation while the video signals for electronic
display systems may be susceptible to 400 Hz sinusoidal modulation. If
the worst-case modulation is unknown or cannot be determined, default
modulations may be
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used. Suggested default values are a 1 kHz sine wave with 80 percent
depth of modulation in the frequency range from 10 kHz to 400 MHz and 1
kHz square wave with greater than 90 percent depth of modulation from
400 MHz to 18 GHz. For frequencies where the unmodulated signal would
cause deviations from normal operation, several different modulating
signals with various waveforms and frequencies should be applied.
Applicants must perform a preliminary hazard analysis to identify
electrical/electronic systems that perform critical functions. The term
``critical'' means those functions whose failure would contribute to or
cause an unsafe condition that would prevent the continued safe flight
and landing of the helicopters. The systems identified by the hazard
analysis as performing critical functions are required to have HIRF
protection. A system may perform both critical and non-critical
functions. Primary electronic flight display systems and their
associated components perform critical functions such as attitude,
altitude, and airspeed indications. HIRF requirements would apply only
to the systems that perform critical functions, including control and
display.
Acceptable system performance would be attained by demonstrating
that the critical function components of the system under consideration
continue to perform their intended function during and after exposure
to required electromagnetic fields. Deviations from system
specifications may be acceptable but must be independently assessed by
the FAA on a case-by-case basis.
Table 1.--VFR Rotorcraft
Field strength volts/meter
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Frequency Peak Average
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10 kHz--100 kHz...................................... 150 150
100 kHz--500 kHz..................................... 180 150
500 kHz--2 MHz....................................... 140 140
2 MHz--30 MHz........................................ 610 610
30 MHz--70 MHz....................................... 80 80
70 MHz--100 MHz...................................... 150 150
100 MHz--200 MHz..................................... 300 140
200 MHz--400 MHz..................................... 160 140
400 MHz--700 MHz..................................... 540 400
700 MHz--1 GHz....................................... 2400 400
1 GHz--2 GHz......................................... 7000 250
2 GHz--4 GHz......................................... 8600 840
4 GHz--6 GHz......................................... 13700 1270
6 GHz--8 GHz......................................... 1800 800
8 GHz--12 GHz........................................ 8000 500
12 GHz--18 GHz....................................... 3300 560
18 GHz--40 GHz....................................... 1800 700
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Table 2.--VFR Rotorcraft
Field strength volts/meter
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Frequency Peak Average
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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--70 MHz....................................... 30 30
70 MHz--100 MHz...................................... 30 30
100 MHz--200 MHz..................................... 150 30
200 MHz--400 MHz..................................... 70 70
400 MHz--700 MHz..................................... 700 80
700 MHz--1 GHz....................................... 1700 240
1 GHz--2 GHz......................................... 5000 360
2 GHz--4 GHz......................................... 4500 360
4 GHz--6 GHz......................................... 7200 300
6 GHz--8 GHz......................................... 2000 330
8 GHz--12 GHz........................................ 3500 270
12 GHz--18 GHz....................................... 3500 330
18 GHz--40 GHz....................................... 780 20
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Applicability
As previously discussed, this special condition is applicable to
Eurocopter Model EC-155 helicopters. Should Eurocopter apply at a later
date for a change to the type certificate to include another model
incorporating the same novel or unusual design feature, the special
condition would apply to that model as well under the provisions of
Sec. 21.101(a)(1).
Conclusion
This action affects only certain novel or unusual design features
on one model series of helicopters. 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 helicopter.
The substance of this special condition has been subjected to the
notice and comment period 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 helicopter,
which is imminent, the FAA has determined that prior public notice and
comment are unnecessary and impracticable, and good cause exists for
adopting this special condition 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 29
Aircraft, Air transportation, Aviation safety, Rotorcraft, Safety.
Authority: The authority citation for these special conditions
is as follows: 42 U.S.C. 7572; 49 U.S.C. 106(g), 40105, 40113,
44701-44702, 44704, 44709, 44711, 44713, 44715, 45303.
The Special Condition
Accordingly, pursuant to the authority delegated to me by the
Administrator, the following special condition is issued as part of the
type certification basis for Eurocopter Model EC-155 helicopters.
Protection for Electrical and Electronic Systems From High-Intensity
Radiated Fields
Each system that performs critical functions must be designed and
installed to ensure that the operation and operational capabilities of
these critical functions are not adversely affected when the helicopter
is exposed to high-intensity radiated fields external to the
helicopter.
Issued in Fort Worth, Texas, on October 31, 2000.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-30303 Filed 11-27-00; 8:45 am]
BILLING CODE 4910-13-P