[Federal Register Volume 64, Number 230 (Wednesday, December 1, 1999)]
[Rules and Regulations]
[Pages 67147-67148]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-31185]
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Rules and Regulations
Federal Register
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This section of the FEDERAL REGISTER contains regulatory documents
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Federal Register / Vol. 64, No. 230 / Wednesday, December 1, 1999 /
Rules and Regulations
[[Page 67147]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 25
[Docket No. NM158; Special Conditions No. 25-152-SC]
Special Conditions: Boeing Model 767-400ER; High-Intensity
Radiated Fields
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the Boeing Model 767-
400ER airplane. This airplane will utilize new avionics/electronic
systems that provide critical data to the flightcrew. 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. These special conditions provide the
additional safety standards that the Administrator considers necessary
to establish a level of safety equivalent to that established by the
existing airworthiness standards.
EFFECTIVE DATE: January 3, 2000.
FOR FURTHER INFORMATION CONTACT: Massoud Sadeghi, FAA, Transport
Airplane Directorate, Aircraft Certification Service, Airplane and
Flight Crew Interface Branch, ANM-111, 1601 Lind Avenue SW., Renton,
Washington, 98055-4056, telephone (425) 227-2117 or facsimile (425)
227-1320.
SUPPLEMENTARY INFORMATION:
Background
On January 14, 1997, the Boeing Commercial Airplane Group applied
for an amendment to Type Certificate No. A1NM to include the new Model
767-400ER, a derivative of the Model 767-200/300 series airplanes. The
Model 767-400ER is a swept-wing, conventional-tail, twin-engine,
turbofan-powered transport airplane. The airframe has been strengthened
to accommodate the increased design loads and weights. The airplane has
a seating capacity of up to 375, and a maximum takeoff weight of
450,000 pounds (204,120 kg). Each engine will be capable of delivering
62,000 pounds of thrust. The flight controls are unchanged beyond those
changes deemed necessary to accommodate the stretched configuration.
Type Certification Basis
Under the provisions of 14 CFR 21.101, Boeing must show that the
Model 767-400ER airplane meets the applicable provisions of the
regulations incorporated by reference in Type Certificate No. A1NM, 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 regulations incorporated by reference in
Type Certificate No. A1NM include 14 CFR part 25, as amended by
Amendments 25-1 through 25-45 with a few exceptions, and certain other
later amended sections of part 25 that are not relevant to these
special conditions. Except for certain earlier amended sections of part
25 that are not relevant to these special conditions, Boeing has chosen
to comply with part 25 as amended by Amendments 25-1 through 25-89, the
applicable regulations in effect on the date of application.
In addition to the applicable airworthiness regulations and special
conditions, the Model 767-400ER must comply with the fuel vent and
exhaust emission requirements of part 34, effective September 10, 1990,
plus any amendments in effect at the time of certification; and the
noise certification requirements of part 36, effective December 1,
1969, as amended by Amendment 36-1 through the amendment in effect at
the time of certification.
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 Model 767-400ER because of a novel
or unusual design feature, special conditions are prescribed under the
provisions of Sec. 21.16.
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. 21.101(b)(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, or should any other model already included on
the same type certificate be modified 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 Model 767-400ER airplane will utilize electrical and electronic
systems that perform critical functions, including the following:
primary electronic flight displays and full authority digital engine
controls (FADEC). These systems may be vulnerable to high-intensity
radiated fields (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 Model 767-400ER. The Model 767-400
requires that new technology electrical and electronic systems 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 and the use
of composite material in the airplane structure, the immunity of
critical digital avionics systems to HIRF must be established.
[[Page 67148]]
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 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 following field
strengths for the frequency ranges indicated.
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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
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The field strengths are expressed in terms of peak root-mean-square
(rms) values.
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 would be applicable
initially to the Model 767-400ER airplane. Should Boeing apply at a
later date for a change to the type certificate to include another
model incorporating the same novel or unusual design feature, these
special conditions would apply to that model as well under the
provisions of Sec. 21.101(a)(1).
Discussion of Comments
Notice of proposed special conditions No. 25-99-06-SC was published
in the Federal Register on July 21, 1999 (64 FR 39095). One comment in
support of the special condition was received.
Conclusion
This action affects certain design features only on the Model 767-
400ER. It is not a rule of general applicability and affects only the
manufacturer who applied to the FAA for approval of these features on
the airplane.
List of Subjects in 14 CFR Part 25
Aircraft, Aviation safety, Reporting and recordkeeping
requirements.
The authority citation for these proposed 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 the Boeing 767-400ER series airplanes.
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 this special condition, 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 November 17, 1999.
Donald L. Riggin,
Acting Manager, Transport Airplane Directorate, Aircraft Certification
Service, ANM-100.
[FR Doc. 99-31185 Filed 11-30-99; 8:45 am]
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