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Special Conditions: Spectrum Aeronautical, LLC Model S-40; Full Authority Digital Engine Control (FADEC) System

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Information about this document as published in the Federal Register.

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Federal Aviation Administration (FAA), DOT.


Final special conditions; request for comments.


These special conditions are issued for the Spectrum Aeronautical, LLC Model S-40 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.


The effective date of these special conditions is May 26, 2009.

We must receive your comments by July 20, 2009.


Mail two copies of your comments to: Federal Aviation Administration, Regional Counsel, ACE-7, Attention: Rules Docket CE297, 901 Locust, Room 506, Kansas City, Missouri 64106. You may deliver two copies to the Rules Docket at the above address. You must mark your comments Docket No. CE297. You may inspect comments in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.

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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.

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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 received. The FAA, therefore, finds that good cause exists for making these special conditions effective upon issuance.

Comments Invited

We invite interested persons 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 file in the docket all comments we receive, as well as a report summarizing each substantive public contact with FAA personnel about these special conditions. You may inspect the docket before and after the comment closing date. If you wish to review the docket in person, go to the address in the ADDRESSES section of this preamble between 7:30 a.m. and 4 p.m. Monday through Friday, except Federal holidays.

We will consider all comments we receive by 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.

If you want us to let you know we received your comments on these special conditions, send us a pre-addressed, stamped postcard on which the docket number appears. We will stamp the date on the postcard and mail it back to you.


On November 21, 2007, Spectrum Aeronautical, LLC applied for a type certificate for their new Model S-40. The Spectrum Model S-40 is a 2 + 9 seat (pilots + passengers) conventionally configured low wing normal category jet airplane with a T-tail and tricycle landing gear. This fiber-wound, all composite aircraft will be certified for day, night, VFR, IFR, and flight into known icing operations with a planned maximum operating altitude of 45,000 feet. The company seeks approval for single pilot operations and will show compliance with Reduced Vertical Separation Minimums (RVSM) requirements.

The Spectrum Model S-40 airplane is equipped with two GE Honda Aero HF120 turbofan engines, each 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 § 23.1309. However, when § 23.1309 was developed, the use of electronic control systems for engines was not envisioned. Therefore, the § 23.1309 requirements were not applicable to systems certificated as part of the engine (reference § 23.1309(f)(1)). Although the parts of the system that are not certificated with the engine could be Start Printed Page 26778evaluated using the criteria of § 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.

In some cases, the airplane that the engine is used in will determine a higher classification (Advisory Circular (AC) 23.1309) than the engine controls are certificated for, which will require that the FADEC/DEEC systems be analyzed at a higher classification. Since November 2005, FADEC special conditions have mandated the classification for § 23.1309 analysis for loss of FADEC control as catastrophic for any airplane. This is not to imply that 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 21.17, Spectrum Aeronautical, LLC must show that the Model S-40 meets the applicable provisions of 14 CFR part 23, as amended by Amendments 23-1 through 23-57, 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 S-40 because of a novel or unusual design feature, special conditions are prescribed under the provisions of § 21.16.

In addition to the applicable airworthiness regulations and special conditions, the Model S-40 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 § 611 of Public Law 92-574, the “Noise Control Act of 1972.”

The FAA issues special conditions, as appropriate, as defined in § 11.19, under § 11.38, and they become part of the type certification basis under § 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 Spectrum Aeronautical, LLC Model S-40 will incorporate the following novel or unusual design features: Electronic engine control system.


As discussed above, these special conditions are applicable to the Model S-40. Should Spectrum Aeronautical, LLC 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 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 Spectrum Aeronautical, LLC Model S-40 is imminent, the FAA finds that good cause exists to make these special conditions effective upon issuance.


This action affects only certain novel or unusual design features on one model, Model S-40, of 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.

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List of Subjects in 14 CFR Part 23

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The authority citation for these special conditions is as follows:

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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.

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The Special Conditions

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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 Spectrum Aeronautical, LLC Model S-40 airplanes.

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1. Electronic Engine Control

The installation of the electronic engine control system must comply with the requirements of § 23.1309(a) through (e) at Amendment 23-49. The intent of this requirement is not to re-evaluate the inherent hardware reliability of the control itself, but rather to determine the effects, including environmental effects addressed in § 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.

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Issued in Kansas City, Missouri on May 26, 2009.

John Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

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[FR Doc. E9-12992 Filed 6-3-09; 8:45 am]