[Federal Register Volume 65, Number 94 (Monday, May 15, 2000)]
[Proposed Rules]
[Pages 30936-30938]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-12142]



Federal Aviation Administration

14 CFR Part 23

[Docket No. CE161; Notice No. 23-00-02-SC]

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed special conditions.


SUMMARY: This notice proposes special conditions 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 proposed 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.

DATES: Comments must be received on or before June 14, 2000.

ADDRESSES: Comments on this proposal may be mailed in duplicate to: 
Federal Aviation Administration, Regional Counsel, ACE-7, Attention: 
Rules Docket, Docket No. CE161, DOT Building, 901 Locust, Kansas City, 
Missouri 64106, or delivered in duplicate to the Regional Counsel at 
the above address. Comments must be marked: Docket No. CE161. Comments 
may be inspected in the Rules Docket weekdays, except Federal holidays, 
between 7:30 a.m. and 4 p.m.

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.


Comments Invited

    Interested persons are invited to participate in the making of 
these proposed special conditions by submitting such written data, 
views, or arguments as they may desire. Communications should identify 

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regulatory docket or notice 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. The 
proposals described in this notice may be changed in light of the 
comments received. All comments received 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 notice must include with those 
comments a self-addressed, stamped postcard on which the following 
statement is made: ``Comments to Docket No. CE161.'' The postcard will 
be date stamped and returned to the commenter.


    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 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 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 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 engines that 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 are proposed for the Morrow Model MB-
300 to provide HIRF protection and to 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.


    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).


    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.

    Authority: The authority citation for these special conditions 
in part 23 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 11.29(b).

The Proposed Special Conditions

    Accordingly, the Federal Aviation Administration (FAA) proposes the 
following special conditions as part of the type certification basis 
for Morrow Model MB-300 airplane.
    1. High Intensity Radiated Fields (HIRF) Protection. In showing

[[Page 30938]]

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.

    (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 
    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 April 28, 2000.
Michael Gallagher,
Manager, Small Airplane Directorate, Aircraft Certification Service.
[FR Doc. 00-12142 Filed 5-12-00; 8:45 am]