Special Conditions: Ayres Corporation; Model LM 200, “Loadmaster”; Flight

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final special conditions.

SUMMARY:

These special conditions are issued for the Ayres Corporation, Model LM 200 airplane. This airplane will have novel or unusual design feature(s) associated with centerline thrust. 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:

September 4, 2001.

FOR FURTHER INFORMATION CONTACT:

Lowell Foster, Federal Aviation Administration, Aircraft Certification Service, Small Airplane Directorate, ACE-111, 901 Locust, Room 301, Kansas City, Missouri, 816-329-4125, fax 816-329-4090.

SUPPLEMENTARY INFORMATION:

Background

On February 9, 2001, Ayres Corporation applied for a type certificate for their new Model LM 200 “Loadmaster.” The Model LM 200 operates with a multiengine/single propeller propulsion system and fixed landing gear. The system consists of two turbine engines driving a single propeller through a combining gearbox. The aircraft is conventional, semi-monocoque, aluminum construction with a high cantilever wing, fixed gear, mechanical and electro-mechanical controls, and it will be unpressurized. Certification will include single pilot and IFR operations.

It is not possible for this airplane to have literal compliance with some commuter category flight test regulations. The Model LM 200 must comply with all commuter category multiengine requirements; however, since this propulsion system will result in centerline thrust, this airplane will not have a V_MC or V_MCG. The propeller is independent of both or either engine such that, with the failure of an engine, the propeller will continue to operate normally but with less torque input. The propeller control system does have failure modes independent of both engines that need to be considered when determining airplane performance. 14 CFR part 23 does not contain adequate or appropriate requirements to address a multiengine/single propeller design that results in centerline thrust.

Type Certification Basis

Under the provisions of 14 CFR 21.17, Ayres Corporation must show that the Model LM 200 “Loadmaster” meets the applicable provisions of part 23, as amended by Amendments 23-1 through 23-53, thereto.

If the Administrator finds that the applicable airworthiness regulations (i.e., part 23) do not contain adequate or appropriate safety standards for the Ayres Corporation Model LM 200 “Loadmaster” 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 LM 200 must comply with the part 23 fuel vent and exhaust emission requirements of 14 CFR part 34 and the part 23 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, as defined in 11.19, are issued in accordance with § 11.38, and become part of the type certification basis in accordance with § 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 § 21.101(a)(1).

Novel or Unusual Design Features

The Model LM 200 will incorporate the following novel or unusual design features: The Model LM 200 will operate with a multiengine/single propeller propulsion system.

Applicability

As discussed above, these special conditions are applicable to the Model LM 200. Should Ayres 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 § 21.101(a)(1).

Discussion of Comments

Notice of proposed special conditions No. 23-01-02-SC for the Ayres Corporation Model LM 200 “Loadmaster” airplane was published on May 8, 2001 (66 FR 23199). No comments were received, and the special conditions are adopted as proposed.

Conclusion

This action affects only certain novel or unusual design features on one model 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.

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, as delegated to me by the Administrator, the following special conditions are issued as part of the type certification basis for the Ayres Corporation Model LM 200 airplanes.

Flight Test Special Conditions

1. In addition to the requirements in § 23.51(c)(1)(i), VEF is also a propeller control system failure speed where the propeller primary control system fails to the configuration most critical to producing thrust, considering all single point failures. The applicant must establish V_EF to be related to the stall speed, and it must not be less than 1.05 V_S1 or greater than 1.2 V_S1.

2. In addition to the requirements in § 23.51(c)(3), to determine a single value for V_R, the applicant must determine and use the most critical of either the one engine inoperative (OEI) configuration or the most critical failed propeller primary control system configuration, whichever is worse. The failed propeller control system configuration must consider all single point failures with both engines operating normally.

3. In addition to the requirement in § 23.51(c)(5), the applicant must determine and use the most critical of either the OEI configuration or the most critical failed propeller primary control system configuration, whichever is worse. The failed propeller control system must consider all single point failures, with both engines operating normally.

4. In § 23.63, where the OEI configuration is required, the applicant must also assume the condition where both engines are operating normally and the propeller primary control system has failed. In the failed propeller primary control system configuration, the applicant must consider all single point failures that result in a propeller configuration most critical to producing thrust.

5. In addition to the requirements in § 23.75(g), the applicant must also determine the increase in landing distance due to failure of the propeller primary control system. This configuration includes both engines operating normally and the propeller primary control system failed to the most critical thrust producing condition considering all single point failures.