[Federal Register Volume 75, Number 75 (Tuesday, April 20, 2010)]
[Rules and Regulations]
[Pages 20518-20520]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-9027]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE306; Special Conditions No. 23-246-SC]


Special Conditions: Cirrus Design Corporation Model SF50 
Airplane; Full Authority Digital Engine Control (FADEC) System

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions; request for comments.

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SUMMARY: These special conditions are issued for the Cirrus Design 
Corporation model SF50 airplane. This airplane will have a novel or 
unusual design feature(s) associated with the use of an electronic 
engine control system instead of a traditional mechanical control 
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.

DATES: The effective date of these special conditions is April 12, 
2010.
    We must receive your comments by May 20, 2010.

ADDRESSES: Mail two copies of your comments to: Federal Aviation 
Administration, Regional Counsel, ACE-7, Attn: Rules Docket No. CE306, 
901 Locust, Kansas City, MO 64106. You may deliver two copies to the 
Regional Counsel at the above address. Mark your comments: Docket No. 
CE306. You may inspect comments in the Rules Docket weekdays, except 
Federal holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Peter L. Rouse, Federal Aviation 
Administration, Aircraft Certification Service, Small Airplane 
Directorate, ACE-111, 901 Locust, Room 301, Kansas City, Missouri 
64106; 816-329-4135, fax 816-329-4090.

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 design 
approval and thus delivery of the affected aircraft. In addition, the 
substance of these special conditions has been subject to the public 
comment process in several prior instances with no substantive comments

[[Page 20519]]

received. The FAA therefore finds that good cause exists for making 
these special conditions 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 by the 
Administrator. The special conditions 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.
    Commenters' wishing the FAA to acknowledge receipt of their 
comments submitted in response to this notice must include a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. CE306.'' The postcard will be date stamped and 
returned to the commenter.

Background

    On September 9, 2008, Cirrus Design Corporation applied for a type 
certificate for their new model SF50. The Cirrus Design Corporation 
model SF50 is a low-wing, five-plus-two-place (2 children), single-
engine turbofan-powered aircraft. It incorporates an Electronic Flight 
Information System (EFIS), pressurized cabin, retractable gear, and a 
V-tail. The turbofan engine is mounted on the upper fuselage/tail cone 
along the aircraft centerline. It is constructed largely of carbon and 
fiberglass composite materials. Like other Cirrus products, the SF50 
includes a ballistically deployed airframe parachute.
    The model SF50 has a maximum operating altitude of 28,000 feet, 
where it cruises at speeds up to 300 KTAS. Its VMO will not 
exceed 0.62 Mach. The maximum takeoff weight will be at or below 6000 
lbs with a range at economy cruise of roughly 1000 nm. Cirrus intends 
for the model SF50 to be certified for single-pilot operations under 14 
CFR part 91 and 14 CFR part 135 operating rules. The following 
operating conditions will be included:
     Day and Night VFR.
     IFR.
     Flight Into Known Icing.
    The Cirrus Design Corporation model SF50 airplane is equipped with 
a Williams International FJ33-5A turbofan engine using an electronic 
engine control system (FADEC) instead of a traditional mechanical 
control system. Even though the engine control system will be 
certificated as part of the engine, the installation of an engine with 
an electronic control system requires evaluation due to critical 
environmental effects and possible effects on or by other airplane 
systems, for example, indirect effects of lightning, radio interference 
with other airplane electronic systems, shared engine and airplane data 
and power sources.
    The regulatory requirements in 14 CFR part 23 for evaluating the 
installation of complex systems, including electronic systems and 
critical environmental effects, 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)). Parts of the system 
that are not certificated with the engine could be evaluated using the 
criteria of Sec.  23.1309. However, the integral nature of these 
systems makes it unfeasible to evaluate the airplane portion of the 
system without including the engine portion of the system.
    In some cases, the airplane that the engine is used in will 
determine a higher classification than the engine controls are 
certificated for, requiring the FADEC systems be analyzed at a higher 
classification. As of November 2005, FADEC special conditions mandated 
the classification for 23.1309 analysis for loss of FADEC control as 
catastrophic for any airplane. This is not to imply an engine failure 
is classified as catastrophic, but that the digital engine control must 
provide an equivalent reliability to mechanical engine controls.

Type Certification Basis

    Under the provisions of 14 CFR part 21, Sec.  21.17, Cirrus Design 
Corporation must show that the model SF50 meets the applicable 
provisions of part 23, as amended by Amendments 23-1 through 23-59, 
thereto.
    If the Administrator finds that the applicable airworthiness 
regulations (i.e., part 23) do not contain adequate or appropriate 
safety standards for the model SF50 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 SF50 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. Also, 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, 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 Cirrus Design Corporation model SF50 will incorporate the 
following novel or unusual design features:
    Electronic engine control system.

Applicability

    As discussed above, these special conditions are applicable to the 
model SF50. Should Cirrus Design 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 as under the provisions of Sec.  
21.101(a)(1).

Conclusion

    This action affects only certain novel or unusual design features 
on the model SF50 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.
    Under standard practice, the effective date of final special 
conditions would be 30 days after the date of publication in the 
Federal Register; however, as the certification date for the Cirrus 
Design Corporation model SF50 is imminent, the FAA finds that good 
cause exists to make these special conditions effective upon issuance.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

Citation

0
The authority citation for these special conditions is as follows:


[[Page 20520]]


    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 Cirrus Design Corporation model SF50 
airplanes.

1. Electronic Engine Control

    The installation of the electronic engine control system must 
comply with the requirements of 14 CFR 23.1309(a) through (e) at 
Amendment 23-49. The intent of this requirement is not to reevaluate 
the inherent hardware reliability of the control itself, but rather 
determine the effects, including environmental effects addressed in 14 
CFR 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; however, the effects of the installation on this data must 
be addressed.
    For these evaluations, the loss of FADEC control will be analyzed 
utilizing the threat levels associated with a catastrophic failure.

    Issued in Kansas City, Missouri, on April 12, 2010.
Steve Thompson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2010-9027 Filed 4-19-10; 8:45 am]
BILLING CODE 4910-13-P