80 FR 57289 - Special Conditions: Cirrus Design Corporation, SF50; Full Authority Digital Engine Control (FADEC) System

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 80, Issue 184 (September 23, 2015)

These special conditions are issued for the Cirrus Design Corporation 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.

[Federal Register Volume 80, Number 184 (Wednesday, September 23, 2015)]
[Rules and Regulations]
[Pages 57289-57291]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-24156]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. FAA-2015-3881; Special Conditions No. 23-267-SC]


Special Conditions: Cirrus Design Corporation, SF50; 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 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 September 23, 
2015.
    We must receive your comments by October 23, 2015.

ADDRESSES: Send comments identified by docket number FAA-2015-3881 
using any of the following methods:
     Federal eRegulations Portal: Go to http://www.regulations.gov and follow the online instructions for sending your 
comments electronically.
     Mail: Send comments to Docket Operations, M-30, U.S. 
Department of Transportation (DOT), 1200 New Jersey Avenue SE., Room 
W12-140, West Building Ground Floor, Washington, DC, 20590-0001.
     Hand Delivery of Courier: Take comments to Docket 
Operations in Room W12-140 of the West Building Ground Floor at 1200 
New Jersey Avenue SE., Washington, DC, between 9 a.m., and 5 p.m., 
Monday through Friday, except Federal holidays.
     Fax: Fax comments to Docket Operations at 202-493-2251.
    Privacy: The FAA will post all comments it receives, without 
change, to http://regulations.gov, including any personal information 
the commenter provides. Using the search function of the docket Web 
site, anyone can find and read the electronic form of all comments 
received into any FAA docket, including the name of the individual 
sending the comment (or signing the comment for an association, 
business, labor union, etc.). DOT's complete Privacy Act Statement can 
be found in the Federal Register published on April 11, 2000 (65 FR 
19477-19478), as well as at http://DocketsInfo.dot.gov.
    Docket: Background documents or comments received may be read at 
http://www.regulations.gov at any time. Follow the online instructions 
for accessing the docket or go to the Docket Operations in Room W12-140 
of the West Building Ground Floor at 1200 New Jersey Avenue SE., 
Washington, DC, between 9 a.m., and 5 p.m., Monday through Friday, 
except Federal holidays.

FOR FURTHER INFORMATION CONTACT: Jeff Pretz, Federal Aviation 
Administration, Small Airplane Directorate, ACE-111, 901 Locust, Room 
301, Kansas City, MO 64106; telephone (816) 329-3239; facsimile (816) 
329-4090.

SUPPLEMENTARY INFORMATION: The FAA has determined, in accordance with 5 
U.S.C. 553(b)(3)(B) and 553(d)(3), that notice and opportunity for 
prior public comment hereon are unnecessary because the substance of 
these special conditions has been subject to the public comment process 
in several prior instances with no substantive comments received. The 
FAA therefore finds that good cause exists for making these special 
conditions effective upon issuance.

------------------------------------------------------------------------
      Special condition number              Company/airplane model
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23-237-SC                            Spectrum Aeronautical Model S-40.
23-246-SC                            Cirrus Design Corporation Model
                                      SF50.
23-253-SC                            Diamond Aircraft Industries Model
                                      DA-40NG.
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Comments Invited

    We invite interested people to take part in this rulemaking by 
sending written comments, data, or views. The most helpful comments 
reference a specific portion of the special conditions, explain the 
reason for any recommended change, and include supporting data. We ask 
that you send us two copies of written comments.
    We will consider all comments we receive on or before the closing 
date for comments. We will consider comments filed late if it is 
possible to do so without incurring expense or delay. We may change 
these special conditions based on the comments we receive.

Background

    On September 9, 2008, Cirrus Design Corporation applied for a type 
certificate for their new Model SF50. On December 11, 2012, Cirrus 
Design Corporation requested to revise the SF50 part 23 certification 
basis to include amendment 23-62. The Cirrus Design Corporation SF50 is 
a low-wing, seven-seat, single-engine turbofan-powered airplane. 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 an 
airframe ballistic parachute system.
    The model SF50 has a maximum operating altitude of 28,000 feet, 
where it cruises at speeds up to 300 knots true airspeed. Its maximum 
operating limit speed (VMO) will not exceed 0.62 Mach. The 
maximum takeoff weight will be at or below 6,000 pounds with a range at 
economy cruise of roughly 1,000 nautical miles. Cirrus intends for the 
SF50 to be certified for single-pilot operations under 14 CFR parts 91 
and 135 operating rules. The following operating conditions will be 
included:

 Day and Night VFR
 IFR
 Flight Into Known Icing

    The Cirrus Design Corporation SF50 airplane is equipped with a 
Williams International FJ33-5A turbofan engine, which uses an 
Electronic Engine Control

[[Page 57290]]

System (EEC, also commonly referred to as a 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 part 23 for evaluating the 
installation of complex systems, including electronic systems and 
critical environmental effects, are contained in Sec. Sec.  23.1306, 
Electrical and electronic system lightning protection; 23.1308, High-
intensity Radiated Fields (HIRF) Protection; and 23.1309, Equipment, 
systems, and installations. However, when Sec.  23.1309 was developed, 
the use of electronic control systems for engines was not envisioned. 
The integral nature of these systems makes it necessary to ensure the 
airplane functions included in the EEC are properly evaluated and that 
the installation does not degrade the EEC reliability, both of which 
are approved under part 33. Sections 23.1306(a) and 23.1308(a) are 
applied to the EEC to ensure it remains equivalent to a mechanical 
system, which is not generally susceptible to the HIRF and lightning 
environments.
    In some cases, the airplane, which the engine is being installed 
in, will determine a higher classification than the engine controls are 
certificated for, requiring the EEC systems be analyzed at a higher 
classification. As of November 2005, EEC special conditions mandated 
the Sec.  23.1309 classification for loss of EEC control as 
catastrophic for any airplane. This is not to imply an engine failure 
is classified as catastrophic, but that the EEC must provide an 
equivalent reliability to mechanical engine controls. In addition, 
Sec. Sec.  23.1141, Powerplant controls: General, paragraph (e) and 
25.901, Powerplant--General--Installation, paragraph (b)(2), are 
applied to provide the fault tolerant design requirements of turbine 
engine mechanical controls to the EEC and ensure adequate inspection 
and maintenance interval of the EEC.

Type Certification Basis

    Under the provisions of 14 CFR 21.17, Cirrus Design Corporation 
must show that the SF50 meets the applicable provisions of part 23, as 
amended by amendments 23-1 through 23-62 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 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 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 and the FAA must issue a finding of 
regulatory adequacy under Sec.  611 of Public Law 92-574, the ``Noise 
Control Act of 1972.''.
    The FAA issues special conditions, as defined in Sec.  11.19, under 
Sec.  11.38 and they become part of the type certification basis under 
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.

Novel or Unusual Design Features

    The SF50 will incorporate the following novel or unusual design 
features:
    Electronic engine control system

Discussion

    As discussed in the summary section, the SF50 makes use of an 
electronic engine control system instead of a traditional mechanical 
control system, which is considered a novel design for this type of 
airplane. The applicable airworthiness regulations do not contain 
adequate or appropriate safety standards for this design feature. 
Mandating a structured assessment to determine potential installation 
issues mitigates the concerns that the addition of an electronic engine 
control may produce failure conditions not previously considered.

Applicability

    As discussed above, these special conditions are applicable to the 
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.

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 affects only the applicant who applied to the FAA for approval of 
these features on the airplane.
    The substance of these special conditions has previously been 
subjected to the notice and comment period as identified above, and has 
been derived without substantive change from those previously issued. 
It is unlikely that prior public comment would result in a significant 
change from the substance contained herein. Therefore, notice and 
opportunity for prior public comment hereon are unnecessary and the FAA 
finds good cause, in accordance with 5 U.S.C. 553(b)(3)(B) and 
553(d)(3), making these special conditions effective upon issuance. The 
FAA is requesting comments to allow interested persons to submit views 
that may not have been submitted in response to the prior opportunities 
for comment described above.

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 Cirrus Design Corporation SF50 
airplane.

1. Full Authority Digital Engine Control (FADEC) System

    a. For electronic engine control system installations, it must be 
established that no single failure or malfunction or probable 
combinations of failures of Electronic Engine Control System (EEC) 
system components will have an effect on the system, as installed in 
the airplane, that causes the LOTC probability of the system to exceed 
those allowed in part 33 certification.
    b. Electronic engine control system installations must be evaluated 
for environmental and atmospheric conditions, including lightning. The 
EEC system lightning and HIRF effects that could result in LOTC must be 
evaluated in accordance with Sec. Sec.  23.1306(a) and 23.1308(a).
    c. The components of the installation must be constructed, 
arranged, and installed to ensure their continued safe

[[Page 57291]]

operation between normal inspections or overhauls.
    d. Functions incorporated into any electronic engine control that 
make it part of any equipment, systems, or installation whose functions 
are beyond that of basic engine control, and which may also introduce 
system failures and malfunctions, are not exempt from Sec.  23.1309 and 
must be shown to meet part 23 levels of safety as derived from Sec.  
23.1309. Part 33 certification data, if applicable, may be used to show 
compliance with any part 23 requirements. If part 33 data is used to 
substantiate compliance with part 23 requirements, then the applicant 
must be able to provide this data for showing or compliance.

    Issued in Kansas City, Missouri on September 14, 2015.
Mel Johnson,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2015-24156 Filed 9-22-15; 8:45 am]
 BILLING CODE 4910-13-P