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###### Department of Transportation

###### Federal Aviation Administration 

          - 14 CFR Part 23 
          - [Docket No. CE165; Notice No. 23-01-02-SC] 

# AGENCY:

Federal Aviation Administration (FAA), DOT. 

# ACTION:

Notice of proposed special conditions. 

# SUMMARY:

This action proposes special conditions for the Ayres Corporation, Model LM 200 airplane. This airplane will have novel or unusual design features associated with centerline thrust. 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 7, 2001. 

# ADDRESSES:

Comments on this proposal may be mailed in duplicate to: Federal Aviation Administration, Regional Counsel, ACE-7, Attention: Rules Docket, Docket No. CE165, 901 Locust, Room 506, Kansas City, Missouri 64106, or delivered in duplicate to the Regional Counsel at the above address. Comments must be marked: CE165. Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4:00 p.m. 

# 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:

## 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 the 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 action 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 action must include with those comments a self-addressed, stamped postcard on which the following statement is made: “Comments to CE165.” The postcard will be date stamped and returned to the commenter.                           ( print page 23200)    

## 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 VMC                     or VMCG. 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 § 611 of Public Law 92-574, the “Noise Control Act of 1972.” 

Special conditions, as appropriate, are issued in accordance with § 11.49 after public notice, as required by §§ 11.28 and 11.29(b), 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). 

## 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

The authority citation for these special conditions is as follows: 49 U.S.C. 106(g); 40113, 44701, 44702, and 44704; 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 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 VEF                     to be related to the stall speed, and it must not be less than 1.05 VS1                     or greater than 1.2 VS1.                 

                    2. In addition to the requirements in § 23.51(c)(3), to determine a single value for VR, 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. 

Issued in Kansas City, Missouri, on April 25, 2001. 

Michael K. Dahl, 

Acting Manager, Small Airplane Directorate, Aircraft Certification Service. 

[FR Doc. 01-11470 Filed 5-7-01; 8:45 am] 

BILLING CODE 4910-13-P