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Special Conditions; Thielert Aircraft Engines (TAE) GmbH, Piper PA 28-161 Cadet, Warrior II and Warrior III Series Airplanes; Diesel Cycle Engine Using Turbine (Jet) Fuel

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Start Preamble

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final special conditions.

SUMMARY:

These special conditions are issued for the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a Thielert Aircraft Engines (TAE) Model TAE 125-1 aircraft diesel engine (ADE). These airplanes will have a novel or unusual design feature(s) associated with the installation of a diesel cycle engine utilizing turbine (jet) fuel. The applicable airworthiness regulations do not contain adequate or appropriate safety standards for installation of this new technology engine. 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:

Effective Date: July 19, 2006.

Start Further Info

FOR FURTHER INFORMATION CONTACT:

Peter L. Rouse, Federal Aviation Administration, Aircraft Certification Service, Small Airplane Directorate, ACE-111, 901 Locust, Kansas City, Missouri, 816-329-4135, fax 816-329-4090.

End Further Info End Preamble Start Supplemental Information

SUPPLEMENTARY INFORMATION:

Background

On February 11, 2002, TAE GmbH, of Lichtenstein, Germany applied for a supplemental type certificate to install a diesel cycle engine utilizing turbine (jet) fuel in Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes. The Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, currently approved under Type Certificate No. 2A13, is a four-place, low wing, fixed tricycle landing gear, conventional planform airplane. The Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes to be modified have gross weights in the range of 2,325 to 2,440 pounds in the normal category. The affected series of airplanes have been equipped with various gasoline reciprocating engines of 160 horsepower.

Expecting industry to reintroduce diesel engine technology into the small airplane fleet, the FAA issued Policy Statement PS-ACE100-2002-004 on May 15, 2004, which identified areas of technological concern involving introduction of new technology diesel engines into small airplanes. For a more detailed summary of the FAA's development of diesel engine requirements, refer to this policy.

The general areas of concern involved the power characteristics of the diesel engines, the use of turbine fuel in an airplane class that has typically been powered by gasoline fueled engines, the vibration characteristics and failure modes of diesel engines. These concerns were identified after review of the historical record of diesel engine use in aircraft and a review of the 14 CFR part 23 regulations, which identified specific regulatory areas that needed to be Start Printed Page 42252evaluated for applicability to diesel engine installations. These concerns are not considered universally applicable to all types of possible diesel engines and diesel engine installations. However, after review of the TAE installation, the TAE engine type, and the requirements applied by the Lufthart Bundesamt, and applying the provisions of the diesel policy, the FAA proposed these fuel system and engine related special conditions. Other special conditions issued in a separate notice included special conditions for HIRF and application of § 23.1309 provisions to the Full Authority Digital Engine Control (FADEC).

Type Certification Basis

Under the provisions of § 21.101, TAE GmbH must show that the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, as changed, continue to meet the applicable provisions of the regulations incorporated by reference in Type Certificate No. 2A13 or the applicable regulations in effect on the date of application for the change. The regulations incorporated by reference in the type certificate are commonly referred to as the “original type certification basis.” The regulations incorporated by reference in Type Certificate No. 2A13 are as follows:

The certification basis of models Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes is:

Civil Air Regulations (CAR) 3 effective May 15, 1956, including Amendments 3-1 and 3-2; paragraph 3.387(d) of Amendment 3-4; paragraphs 3.304 and 3.705 of Amendment 3-7, effective May 3, 1962; FAR 23.955 and 23.959 as amended by Amendment 23-7, effective September 14, 1969; FAR 23.1557(c)(1) as amended by Amendment 23-18, effective May 2, 1977; FAR 23.1327 and 23.1547 as amended by Amendment 23-20, effective September 1, 1977; and FAR 36, effective December 1, 1969, through Amendment 36-4.

Equivalent Safety Items for:

Airspeed Indicator: CAR 3.757.

14 CFR part 23, at Amendment level 23-51, applicable to the areas of change:

14 CFR part 23, §§ 23.1; 23.3; 23.21; 23.23; 23.25; 23.29; 23.33; 23.45; 23.49; 23.51; 23.53; 23.63; 23.65; 23.69; 23.71; 23.73; 23.77; 23.141; 23.143; 23.145; 23.151; 23.153; 23.155; 23.171; 23.173; 23.175; 23.177; 23.201; 23.221; 23.231; 23.251; 23.301; 23.303; 23.305; 23.307; 23.321; 23.335; 23.337; 23.341; 23.343; 23.361; 23.361(b)(1); 23.361(c)(3); 23.363; 23.371; 23.572; 23.573; 23.574; 23.601; 23.603; 23.605; 23.607; 23.609; 23.611; 23.613; 23.619; 23.621; 23.623; 23.625; 23.627; CAR 3.159; 23.773; 23.777; 23.777(d); 23.779; 23.779(b); 23.781; 23.831; 23.863; 23.865; 23.867; 23.901; 23.901(d)(1); 23.903; 23.905; 23.907; 23.909; 23.925; 23.929; 23.939; 23.943; 23.951; 23.951(c); 23.954; 23.955; 23.959; 23.961; 23.963; 23.965; 23.967; 23.969; 23.971; 23.973; 23.973(f); 23.975; 23.977; 23.977(a)(2) in place of 23.977(a)(1); 23.991; 23.993; 23.994; 23.995; 23.997; 23.999; 23.1011; 23.1013; 23.1015; 23.1017; 23.1019; 23.1021; 23.1023; 23.1041; 23.1043; 23.1047; 23.1061; 23.1063; 23.1091; 23.1093; 23.1103; 23.1107; 23.1121; 23.1123; 23.1141; 23.1143; 23.1145; 23.1163; 23.1165; 23.1181; 23.1182; 23.1183; 23.1191; 23.1193; 23.1301; 23.1305; 23.1305(c)(8); 23.1309; 23.1311; 23.1321; 23.1322; 23.1327; 23.1331; 23.1337; 23.1351; 23.1353; 23.1357; 23.1359; 23.1361; 23.1365; 23.1367; 23.1381; 23.1431; 23.1461; 23.1501; 23.1519; 23.1521; 23.1521(d); 23.1527; 23.1529; 23.1541; 23.1543; 23.1549; 23.1551; 23.1555; 23.1557; 23.1557(c)(1)(ii), in place of §§ 23.1557(c)(i); 23.1567; 23.1581; 23.1583; 23.1585; 23.1587 and 23.1589.

Equivalent levels of safety for:

Cockpit controls: 23.777(d).

Motion and effect of cockpit controls: 23.779(b).

Liquid Cooling—Installation: 23.1061.

Ignition switches: 23.1145.

The type certification basis includes exemptions, if any; equivalent level of safety findings, if any; and the special conditions adopted by this rulemaking action.

In addition, if the regulations incorporated by reference do not provide adequate standards with respect to the change, the applicant must comply with certain regulations in effect on the date of application for the change. The type certification basis for the modified airplanes is as stated previously with the following modifications.

If the Administrator finds that the applicable airworthiness regulations (i.e., part 23) do not contain adequate or appropriate safety standards for the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE, 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 Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE, must comply with the 14 CFR part 21, § 21.115 noise certification requirements of 14 CFR part 36.

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 § 21.101.

Special conditions are initially applicable to the model for which they are issued. Should the applicant apply for a supplemental type certificate to modify any other model included on the same type certificate to incorporate the same novel or unusual design feature, the special conditions would also apply to the other model under the provisions of § 21.101.

Novel or Unusual Design Features

The Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes will incorporate the following novel or unusual design features:

Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE, will incorporate an aircraft diesel engine utilizing turbine (jet) fuel.

Discussion of Comments

A notice of proposed special conditions No. 23-06-04-SC for the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE, was published on June 14, 2006 (71 FR 34288). No comments were received, and the special conditions are adopted as proposed.

Applicability

As discussed above, these special conditions are applicable to the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE. Should TAE GmbH apply at a later date for a supplemental type certificate to modify any other model included on Type Certificate No. 2A13 to incorporate the same novel or unusual design feature, the special conditions would apply to that model as well under the provisions of § 21.101.

Conclusion

This action affects only certain novel or unusual design features on the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE. 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.

Start List of Subjects

List of Subjects in 14 CFR Part 23

End List of Subjects Start Printed Page 42253

Citation

Start Amendment Part

The authority citation for these special conditions is as follows:

End Amendment Part Start Authority

Authority: 49 U.S.C. 106(g), 40113 and 44701; 14 CFR 21.16 and 21.101; and 14 CFR 11.38 and 11.19.

End Authority

The Special Conditions

Start Amendment Part

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 the Piper PA 28-161 Cadet, Warrior II and Warrior III series airplanes, with the installation of a TAE 125-1 ADE.

End Amendment Part

1. Engine torque (Provisions similar to § 23.361, paragraphs (b)(1) and (c)(3)):

(a) For diesel engine installations, the engine mounts and supporting structure must be designed to withstand the following:

(1) A limit engine torque load imposed by sudden engine stoppage due to malfunction or structural failure.

The effects of sudden engine stoppage may alternately be mitigated to an acceptable level by utilization of isolators, dampers, clutches and similar provisions, so that unacceptable load levels are not imposed on the previously certificated structure.

(b) The limit engine torque to be considered under paragraph 14 CFR part 23, § 23.361(a) must be obtained by multiplying the mean torque by a factor of four for diesel cycle engines.

(1) If a factor of less than four is utilized, it must be shown that the limit torque imposed on the engine mount is consistent with the provisions of § 23.361(c), that is, it must be shown that the utilization of the factors listed in § 23.361(c)(3) will result in limit torques being imposed on the mount that are equivalent or less than those imposed by a conventional gasoline reciprocating engine.

2. Powerplant—Installation (Provisions similar to § 23.901(d)(1) for turbine engines):

Considering the vibration characteristics of diesel engines, the applicant must comply with the following:

(a) Each diesel engine installation must be constructed and arranged to result in vibration characteristics that—

(1) Do not exceed those established during the type certification of the engine; and

(2) Do not exceed vibration characteristics that a previously certificated airframe structure has been approved for—

(i) Unless such vibration characteristics are shown to have no effect on safety or continued airworthiness, or

(ii) Unless mitigated to an acceptable level by utilization of isolators, dampers, clutches and similar provisions, so that unacceptable vibration levels are not imposed on the previously certificated structure.

3. Powerplant—Fuel System—Fuel system with water saturated fuel (Compliance with § 23.951 requirements):

Considering the fuel types used by diesel engines, the applicant must comply with the following:

Each fuel system for a diesel engine must be capable of sustained operation throughout its flow and pressure range with fuel initially saturated with water at 80 °F and having 0.75cc of free water per gallon added and cooled to the most critical condition for icing likely to be encountered in operation.

Methods of compliance that are acceptable for turbine engine fuel systems requirements of § 23.951(c) are also considered acceptable for this requirement.

4. Powerplant—Fuel System—Fuel system hot weather operation (Compliance with § 23.961 requirements):

In place of compliance with § 23.961, the applicant must comply with the following:

Each fuel system must be free from vapor lock when using fuel at its critical temperature, with respect to vapor formation, when operating the airplane in all critical operating and environmental conditions for which approval is requested. For turbine fuel, or for aircraft equipped with diesel cycle engines that use turbine or diesel type fuels, the initial temperature must be 110 °F, −0°, +5° or the maximum outside air temperature for which approval is requested, whichever is more critical.

The fuel system must be in an operational configuration that will yield the most adverse, that is, conservative results.

To comply with this requirement, the applicant must use the turbine fuel requirements and must substantiate these by flight-testing, as described in Advisory Circular AC 23-8B, Flight Test Guide for Certification of Part 23 Airplanes.

5. Powerplant—Fuel system—Fuel tank filler connection (Compliance with § 23.973(f) requirements):

In place of compliance with § 23.973(e) and (f), the applicant must comply with the following:

For airplanes that operate on turbine or diesel type fuels, the inside diameter of the fuel filler opening must be no smaller than 2.95 inches.

6. Powerplant—Fuel system—Fuel tank outlet (Compliance with § 23.977 requirements):

In place of compliance with § 23.977(a)(1) the applicant will comply with § 23.977(a)(2), except “diesel” replaces “turbine.”

There must be a fuel strainer for the fuel tank outlet or for the booster pump. This strainer must, for diesel engine powered airplanes, prevent the passage of any object that could restrict fuel flow or damage any fuel system component.

7. Powerplant—Powerplant Controls and Accessories—Engine ignition systems (Compliance with § 23.1165 requirements):

Considering that the FADEC provides the same function as an ignition system for this diesel engine, in place of compliance to § 23.1165, the applicant will comply with the following:

The electrical system must comply with the following requirements:

(a) In case of failure of one power supply of the electrical system, there will be no significant engine power change. The electrical power supply to the FADEC must remain stable in such a failure.

(b) The transition from the actual engine electrical network (FADEC network) to the remaining electrical system should be made at a single point only. If several transitions (for example, redundancy reasons) are needed, then the number of the transitions must be kept as small as possible.

(c) There must be the ability to separate the FADEC power supply (alternator) from the battery and from the remaining electrical system.

(d) In case of loss of alternator power, the installation must guarantee that the battery will provide the power for an appropriate time after appropriate warning to the pilot. This period must be at least 120 minutes.

(e) FADEC, alternator and battery must be interconnected in an appropriate way, so that in case of loss of battery power, the supply to the FADEC is guaranteed by the alternator.

8. Equipment—General—Powerplant Instruments (Compliance with § 23.1305 requirements):

In place of compliance with § 23.1305, the applicant will comply with the following:

The following are required powerplant instruments:

(a) A fuel quantity indicator for each fuel tank, installed in accordance with § 23.1337(b).

(b) An oil pressure indicator.

(c) An oil temperature indicator.

(d) A tachometer indicating propeller speed.

(e) A coolant temperature indicator. Start Printed Page 42254

(f) An indicating means for the fuel strainer or filter required by § 23.997 to indicate the occurrence of contamination of the strainer or filter before it reaches the capacity established in accordance with § 23.997(d).

Alternately, no indicator is required if the engine can operate normally for a specified period with the fuel strainer exposed to the maximum fuel contamination as specified in MIL-5007D and provisions for replacing the fuel filter at this specified period (or a shorter period) are included in the maintenance schedule for the engine installation.

(g) Power setting, in percentage.

(h) Fuel temperature.

(i) Fuel flow (engine fuel consumption).

9. Operating Limitations and Information—Powerplant limitations—Fuel grade or designation (Compliance with § 23.1521(d) requirements):

Instead of compliance with § 23.1521(d), the applicant must comply with the following:

The minimum fuel designation (for diesel engines) must be established so that it is not less than that required for the operation of the engines within the limitations in paragraphs (b) and (c) of § 23.1521.

10. Markings And Placards—Miscellaneous markings and placards—Fuel, oil, and coolant filler openings (Compliance with § 23.1557(c)(1) requirements):

Instead of compliance with § 23.1557(c)(1)(i), the applicant must comply with the following:

Fuel filler openings must be marked at or near the filler cover with—

For diesel engine-powered airplanes—

(a) The words “Jet Fuel”; and

(b) The permissible fuel designations, or references to the Airplane Flight Manual (AFM) for permissible fuel designations.

(c) A warning placard or note that states the following or similar: “Warning—this airplane equipped with an aircraft diesel engine, service with approved fuels only.”

The colors of this warning placard should be black and white.

11. Powerplant—Fuel system—Fuel-Freezing:

If the fuel in the tanks cannot be shown to flow suitably under all possible temperature conditions, then fuel temperature limitations are required. These will be considered as part of the essential operating parameters for the aircraft and must be limitations.

(1) The takeoff temperature limitation must be determined by testing or analysis to define the minimum cold-soaked temperature of the fuel that the airplane can operate on.

(2) The minimum operating temperature limitation must be determined by testing to define the minimum operating temperature acceptable after takeoff (with minimum takeoff temperature established in (1) above).

12. Powerplant Installation—Vibration levels:

Vibration levels throughout the engine operating range must be evaluated and:

(1) Vibration levels imposed on the airframe must be less than or equivalent to those of the gasoline engine; or

(2) Any vibration level that is higher than that imposed on the airframe by the replaced gasoline engine must be considered in the modification and the effects on the technical areas covered by the following paragraphs must be investigated:

14 CFR part 23, §§ 23.251; 23.613; 23.627; CAR 3.159; 23.572; 23.573; 23.574 and 23.901.

Vibration levels imposed on the airframe can be mitigated to an acceptable level by utilization of isolators, dampers, clutches and similar provisions, so that unacceptable vibration levels are not imposed on the previously certificated structure.

13. Powerplant Installation—One cylinder inoperative:

It must be shown by test or analysis, or by a combination of methods, that the airframe can withstand the shaking or vibratory forces imposed by the engine if a cylinder becomes inoperative. Diesel engines of conventional design typically have extremely high levels of vibration when a cylinder becomes inoperative. Data must be provided to the airframe installer/modifier so either appropriate design considerations or operating procedures, or both, can be developed to prevent airframe and propeller damage.

14. Powerplant Installation—High Energy Engine Fragments:

It may be possible for diesel engine cylinders (or portions thereof) to fail and physically separate from the engine at high velocity (due to the high internal pressures). This failure mode will be considered possible in engine designs with removable cylinders or other non-integral block designs. The following is required:

(1) It must be shown that the engine construction type (massive or integral block with non-removable cylinders) is inherently resistant to liberating high energy fragments in the event of a catastrophic engine failure; or,

(2) It must be shown by the design of the engine, that engine cylinders, other engine components or portions thereof (fragments) cannot be shed or blown off of the engine in the event of a catastrophic engine failure; or

(3) It must be shown that all possible liberated engine parts or components do not have adequate energy to penetrate engine cowlings; or

(4) Assuming infinite fragment energy, and analyzing the trajectory of the probable fragments and components, any hazard due to liberated engine parts or components will be minimized and the possibility of crew injury is eliminated. Minimization must be considered during initial design and not presented as an analysis after design completion.

Start Signature

Issued in Kansas City, Missouri, on July 19, 2006.

John R. Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

End Signature End Supplemental Information

[FR Doc. E6-11878 Filed 7-25-06; 8:45 am]

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