[Federal Register Volume 67, Number 110 (Friday, June 7, 2002)]
[Rules and Regulations]
[Pages 39264-39265]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-14351]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 23
[Docket No. CE174; Special Conditions No. 23-119-SC]
Special Conditions: Liberty Aerospace, Model XL-2 Airplane,
Installation of Full Authority Digital Engine Control (FADEC) System
and the Protection of the System From the Effects of High Intensity
Radiated Fields (HIRF)
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final special conditions.
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SUMMARY: These special conditions are issued for the Liberty Aerospace
Model XL-2 airplane. This airplane will have a novel or unusual design
feature(s) associated with the installation of an engine that uses an
electronic engine control system in place of the engine's mechanical
system. The applicable airworthiness regulations do not contain
adequate or appropriate safety standards for this design feature. These
special conditions contain 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: July 8, 2002.
FOR FURTHER INFORMATION CONTACT: Ervin Dvorak, Federal Aviation
Administration, Aircraft Certification Service, Small Airplane
Directorate, ACE-111, 901 Locust, Room 301, Kansas City, Missouri
64106; 816-329-4123, fax 816-329-4090.
SUPPLEMENTARY INFORMATION:
Background
On October 26, 2000, Liberty Aerospace applied for a type
certificate for their new Model XL-2. The Model XL-2 is powered by one
reciprocating engine equipped with an electronic engine control system
with full authority capability in place of the hydromechanical control
system.
Type Certification Basis
Under the provisions of 14 CFR 21.17, Liberty Aerospace must show
that the Model XL-2 meets the applicable provisions of 14 CFR part 23,
as amended by Amendments 23-1 through 23-53 thereto.
If the Administrator finds that the applicable airworthiness
regulations (i.e., 14 CFR part 23) do not contain adequate or
appropriate safety standards for the Model XL-2 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, the Model XL-2 must comply with the fuel vent and exhaust
emission requirements of 14 CFR part 34 and 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, as defined in 11.19, are issued
in accordance with Sec. 11.38, 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
The Model XL-2 will incorporate the following novel or unusual
design features:
Liberty Aerospace, Model XL-2 airplane will use an engine that
includes an electronic control system with full engine authority
capability.
Many advanced electronic systems are prone to either upsets or
damage, or both, at energy levels lower than analog systems. The
increasing use of high power radio frequency emitters mandates
requirements for improved high intensity radiated fields (HIRF)
protection for electrical and electronic equipment. Since the
electronic engine control system used on the Liberty Aerospace, Model
XL-2 will perform critical functions, provisions for protection from
the effects of HIRF fields should be considered and, if necessary,
incorporated into the airplane design data. The FAA policy contained in
Notice 8110.71, dated April 2, 1998, establishes the HIRF energy levels
that airplanes will be exposed to in service. The guidelines set forth
in this Notice are the result of an Aircraft Certification Service
review of existing policy on HIRF, in light of the ongoing work of the
ARAC Electromagnetic Effects Harmonization Working Group (EEHWG). The
EEHWG adopted a set of HIRF environment levels in November 1997 that
were agreed upon by the FAA, JAA, and industry participants. As a
result, the HIRF environments in this notice reflect the environment
levels recommended by this working group. This notice states that a
full authority digital engine control is an example of a system that
should address the HIRF environments.
Even though the control system will be certificated as part of the
engine, the installation of an engine with an electronic control system
requires evaluation due to the possible effects on or by other airplane
systems (e.g., radio interference with other airplane electronic
systems, shared engine and airplane power sources). The regulatory
requirements in 14 CFR part 23 for evaluating the installation of
complex systems, including electronic systems, are contained in
Sec. 23.1309. However, when Sec. 23.1309 was developed, the use of
electronic control systems for engines was not envisioned; therefore,
the Sec. 23.1309 requirements were not applicable to systems
certificated as part of the engine (reference Sec. 23.1309(f)(1)).
Also, electronic control systems often require inputs from airplane
data and power sources and outputs to other airplane systems (e.g.,
automated cockpit powerplant controls such as mixture setting).
Although the parts of the system that are not certificated with the
engine could be evaluated using the criteria of Sec. 23.1309, the
integral nature of systems such as these makes it unfeasible to
evaluate the airplane portion of the system without including the
engine portion of the system. However, Sec. 23.1309(f)(1) again
prevents complete evaluation of the installed airplane system since
evaluation of the engine system's effects is not required.
Therefore, special conditions are proposed for the Liberty
Aerospace, Model XL-2 to provide HIRF protection and to evaluate the
installation of the electronic engine control system for
[[Page 39265]]
compliance with the requirements of Sec. 23.1309(a) through (e) at
Amendment 23-46.
Discussion of Comments
Notice of proposed special conditions No. 23-02-01-SC for the
Liberty Aerospace Model XL-2 airplanes was published on March 14, 2002
(67 FR 11451). No comments were received, and the special conditions
are adopted as proposed.
Applicability
As discussed above, these special conditions are applicable to the
Model XL-2. Should Liberty Aerospace 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 conditions would apply to
that model as well under the provisions of Sec. 21.101.
Conclusion
This action affects only certain novel or unusual design features
on one model XL-2 of airplanes. It is not a rule of general
applicability, and it affects only the applicant who applied to the FAA
for approval of these features on the airplane.
List of Subjects in 14 CFR Part 23
Aircraft, Aviation safety, Signs and symbols.
Citation
The authority citation for these special conditions is as follows:
Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and
21.17; and 14 CFR 11.38 and 11.19.
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 Liberty Aerospace Model XL-2
airplanes.
1. High Intensity Radiated Fields (HIRF) Protection. In showing
compliance with 14 CFR part 21 and the airworthiness requirements of 14
CFR part 23, protection against hazards caused by exposure to HIRF
fields for the full authority digital engine control system, which
performs critical functions, must be considered. To prevent this
occurrence, the electronic engine control system must be designed and
installed to ensure that the operation and operational capabilities of
this critical system are not adversely affected when the airplane is
exposed to high energy radio fields.
At this time, the FAA and other airworthiness authorities are
unable to precisely define or control the HIRF energy level to which
the airplane will be exposed in service; therefore, the FAA hereby
defines two acceptable interim methods for complying with the
requirement for protection of systems that perform critical functions.
(1) The applicant may demonstrate that the operation and
operational capability of the installed electrical and electronic
systems that perform critical functions are not adversely affected when
the aircraft is exposed to the external HIRF threat environment defined
in the following table:
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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 root-mean-square
(rms) values.
or,
(2) The applicant may demonstrate by a system test and analysis
that the electrical and electronic systems that perform critical
functions can withstand a minimum threat of 100 volts per meter peak
electrical strength, without the benefit of airplane structural
shielding, in the frequency range of 10 KHz to 18 GHz. When using this
test to show compliance with the HIRF requirements, no credit is given
for signal attenuation due to installation. Data used for engine
certification may be used, when appropriate, for airplane
certification.
2. Electronic Engine Control System. The installation of the
electronic engine control system must comply with the requirements of
Sec. 23.1309(a) through (e) at Amendment 23-46. The intent of this
requirement is not to re-evaluate the inherent hardware reliability of
the control itself, but rather determine the effects, including
environmental effects addressed in Sec. 23.1309(e), on the airplane
systems and engine control system when installing the control on the
airplane. When appropriate, engine certification data may be used when
showing compliance with this requirement.
Issued in Kansas City, Missouri on May 29, 2002.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 02-14351 Filed 6-6-02; 8:45 am]
BILLING CODE 4910-13-P