[Federal Register Volume 65, Number 183 (Wednesday, September 20, 2000)]
[Rules and Regulations]
[Pages 56779-56780]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-24141]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE161; Special Conditions No. 23-104-SC]


Special Conditions: Installation of Full Authority Digital Engine 
Control (FADEC) System on Morrow Aircraft Corporation Model MB-300 
Airplane

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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SUMMARY: These special conditions are issued for the Morrow Aircraft 
Corporation Model MB-300, which will use a FADEC System. This airplane 
will have a novel or unusual design feature 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: October 20, 2000.

FOR FURTHER INFORMATION CONTACT: Randy Griffith, Aerospace Engineer, 
Federal Aviation Administration, Aircraft Certification Service, Small 
Airplane Directorate, ACE-111, 901 Locust, Room 301, Kansas City, 
Missouri, 816-329-4126, fax 816-329-4090.

SUPPLEMENTARY INFORMATION:

Background

    On March 5, 1999, Morrow Aircraft Corporation applied for a type 
certificate for the Model MB-300 airplane. The Model MB-300 is a small, 
normal category airplane. The airplane is powered by two reciprocating 
engines, each 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, Morrow Aircraft Corporation 
must show that the Model MB-300 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 MB-300 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 MB-300 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 Sec. 611 of Public Law 92-574, the 
``Noise Control Act of 1972.''
    Special conditions, as appropriate, are issued in accordance with 
Sec. 11.49 after public notice, 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

    The Morrow Model MB-300 will incorporate the following novel or 
unusual design features:
    The Morrow Model MB-300 airplane will use two engines that each 
include 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 Morrow Model MB-300 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 for the Morrow Model MB-300 provide 
HIRF protection and evaluate the installation of the electronic engine 
control system for compliance with the requirements of Sec. 23.1309(a) 
through (e) at Amendment 23-53.

Discussion of Comments

    A notice of proposed special conditions No. 23-00-02-SC for the 
Morrow Aircraft Corporation Model MB-300 airplane was published on May 
15, 2000 (65 FR 30936). No comments were received, and the special 
conditions are adopted as proposed.

[[Page 56780]]

Applicability

    As discussed above, these special conditions are applicable to the 
Morrow Model MB-300. Should Morrow Aircraft Corporation 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(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on one model, the Morrow Model MB-300 airplane. 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 11.28 and 49.

The Special Conditions

    Accordingly, under the authority delegated to me by the 
Administrator, the following special conditions are issued as part of 
the type certification basis for Morrow Model MB-300 airplane.
    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:

------------------------------------------------------------------------
                                                  Field strength (volts
                                                       per meter)
                   Frequency                   -------------------------
                                                    Peak       Average
------------------------------------------------------------------------
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 items that 
affect the electronic engine control system must comply with the 
requirements of Sec. 23.1309(a) through (e) including applicable 
amendments through Amendment 23-53. Data used for engine certification 
may be used, when appropriate, for airplane certification.

    Issued in Kansas City, Missouri on September 6, 2000.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 00-24141 Filed 9-19-00; 8:45 am]
BILLING CODE 4910-13-P