Source: https://www.federalregister.gov/documents/2005/06/28/05-12720/special-conditions-diamond-aircraft-industries-da-42-diesel-cycle-engine-using-turbine-jet-fuel
Timestamp: 2018-09-22 18:40:49
Document Index: 401709713

Matched Legal Cases: ['art 23', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', 'art 23', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', '§\u200923', 'art 23', '§\u200921', 'art 23', 'art 36', '§\u200911', '§\u200911', '§\u200921', '§\u200921', '§\u200923', '§\u200923', '§\u200923', '§\u200923', 'art 23', '§\u200923', '§\u200923', '§\u200991', '§\u200991', '§\u200923', 'art 23']

Federal Register :: Special Conditions: Diamond Aircraft Industries, DA-42; Diesel Cycle Engine Using Turbine (Jet) Fuel
Special Conditions: Diamond Aircraft Industries, DA-42; Diesel Cycle Engine Using Turbine (Jet) Fuel
The effective date of these special conditions is June 22, 2005. Comments must be received on or before July 28, 2005.
70 FR 37016
Docket No. CE227
Special Condition No. 23-169-SC
05-12720
https://www.federalregister.gov/d/05-12720 https://www.federalregister.gov/d/05-12720
These special conditions are issued for the Diamond Aircraft Industries (DAI) DA-42 airplane. This airplane 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.
The effective date of these special conditions is June 22, 2005. Start Printed Page 37017Comments must be received on or before July 28, 2005.
Comments on these special conditions may be mailed in duplicate to: Federal Aviation Administration, Regional Counsel, ACE-7, Attention: Rules Docket, Docket No. CE227, 901 Locust, Room 506, Kansas City, Missouri 64106, or delivered in duplicate to the Regional Counsel at the above address. Comments must be marked: CE227. Comments may be inspected in the Rules Docket weekdays, except Federal holidays, between 7:30 a.m. and 4 p.m.
The FAA has determined that notice and opportunity for prior public comment hereon are impracticable because these procedures would significantly delay issuance of the approval design and thus delivery of the affected aircraft. The FAA therefore finds that good cause exists for making these special conditions effective upon issuance.
Interested persons are invited to submit such written data, views, or arguments, as they may desire. Communications should identify the regulatory docket or special condition 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 special conditions 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 notice must include with those comments a self-addressed, stamped postcard on which the following statement is made: “Comments to CE227.” The postcard will be date stamped and returned to the commenter.
Under the Bilateral Airworthiness Agreement (BAA) between the USA and the Austrian Exporting Civil Aviation Authority (ECAA), the Austro Control GmbH (ACG), the DAI applied for U.S. Type Certification of Diamond Aircraft Industries (DAI) Model DA-42 on August 2, 2004, through the European Aviation Safety Agency (EASA). The DAI DA-42 aircraft is a new fully composite, four place, twin-engine airplane with retractable gear, cantilever low wing and T-tail. EASA certified the airplane on type certificate number A005, dated May 13, 2004. The airplane is powered by two Thielert Aircraft Engines GmbH (Thielert) TAE 125-01 aircraft diesel engines (ADE), type certificated in the United States, type certificate number E00069EN.
Expecting the reintroduction of 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 a review of the 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 evaluated 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 DAI installation, the Thielert engine type, and the requirements applied by the ACG, and after applying the provisions of the diesel policy, the FAA proposes these fuel system and engine related special conditions. Other special conditions issued in a separate notice include special conditions for HIRF and application of § 23.1309 provisions to the Full Authority Digital Engine Control (FADEC).
Several major concerns were identified in developing FAA policy. These include installing the diesel engine and noting its vibration levels under both normal operating conditions and when one cylinder is inoperative. The concerns also include accommodating turbine fuels in airplane systems that have generally evolved based on gasoline requirements, anticipated use of a FADEC to control the engine, and appropriate limitations and indications for a diesel engine powered airplane. The general concerns associated with the aircraft diesel engine installation are as follows: Installation and Vibration Requirements, Fuel and Fuel System Related Requirements, FADEC and Electrical System Requirements, Limitations and Indications.
Installation and Vibration Requirements: These special conditions include requirements similar to the requirements of § 23.901(d)(1) for turbine engines. In addition to the requirements of § 23.901 applied to reciprocating engines, the applicant will be required to construct and arrange each diesel engine installation to result in vibration characteristics that do not exceed those established during the type certification of the engine. These vibration levels must not exceed vibration characteristics that a previously certificated airframe structure has been approved for, unless such vibration characteristics are shown to have no effect on safety or continued airworthiness. The engine limit torque design requirements as specified in § 23.361 are also modified.
An additional requirement to consider vibration levels and/or effects of an inoperative cylinder was imposed. Also, a requirement to evaluate the engine design for the possibility of, or effect of, liberating high-energy engine fragments, in the event of a catastrophic engine failure, requirements was added.
Due to the use of turbine fuel, the applicant will comply with § 23.977(a)(2), and § 23.977(a)(1) will not apply. “Turbine engines” will be interpreted to mean “aircraft diesel engine” for this requirement. An additional requirement to consider the possibility of fuel freezing was imposed. Start Printed Page 37018
The transition from the actual engine electrical network (FADEC) to the remaining electrical system with the consumer's, avionics, communication, etc., should be made by a single point only. If several transitions (e.g., for redundancy reasons) are needed, then the number of the transitions must be kept as small as possible.
FADEC, alternator, and battery must be interconnected in an appropriate way so, in case of loss of battery power, the supply of the FADEC is guaranteed by the alternator.
Section 23.1305(a) and § 23.1305(b)(2) will apply, except that propeller revolutions per minute (RPM) will be displayed. Sections 23.1305(b)(4), 23.1305(b)(5), and 23.1305(b)(7) are deleted.
Additional critical engine parameters for this installation that will be displayed include:
Under the provisions of 14 CFR 21.17, Diamond Aircraft Industries must show that the DA-42 meets the applicable provisions of part 23, as amended by Amendments 23-1 through 23-51 thereto. In addition, the certification basis includes special conditions and equivalent levels of safety for the following:
Engine torque (Provisions similar to § 23.361, paragraphs (b)(1) and (c)(3))
Powerplant—Installation (Provisions similar to § 23.901(d)(1) for turbine engines)
Powerplant—Fuel System—Fuel system with water saturated fuel (Compliance with § 23.951 requirements)
Powerplant—Fuel System—Fuel system hot weather operation (Compliance with § 23.961 requirements)
Powerplant—Fuel system—Fuel tank filler connection (Compliance with § 23.973(f) requirements)
Powerplant—Fuel system—Fuel tank outlet (Compliance with § 23.977 requirements)
Powerplant—Powerplant Controls and Accessories—Engine ignition systems (Compliance with § 23.1165 requirements)
Equipment—General—Powerplant Instruments (Compliance with § 23.1305 requirements)
Operating Limitations and Information—Powerplant limitations—Fuel grade or designation (Compliance with § 23.1521(d) requirements)
Markings And Placards—Miscellaneous markings and placards—Fuel, oil, and coolant filler openings (Compliance with § 23.1557(c)(1) requirements)
Powerplant—Fuel system—Fuel-Freezing
Powerplant Installation—Vibration levels
Powerplant Installation—One cylinder inoperative
Powerplant Installation—High Energy Engine Fragments
If the Administrator finds that the applicable airworthiness regulations (i.e., part 23) do not contain adequate or appropriate safety standards for the Diamond Aircraft Industries DA-42 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 Diamond Aircraft Industries DA-42 must comply with the part 23 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 § 21.17.
The Diamond Aircraft Industries DA-42 will incorporate the following novel or unusual design feature:
The Diamond Aircraft Industries DA-42 will incorporate an aircraft diesel engine using turbine (jet) fuel.
As discussed above, these special conditions are applicable to the Diamond Aircraft Industries DA-42. Should Diamond Aircraft Industries 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 condition would apply to that model as well under the provisions of § 21.101.
The substance of these special conditions has been subjected to the notice and comment period in a prior instance 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. For this reason, and because a delay would significantly affect the certification of the airplane, which is imminent, the FAA has determined that prior public notice and comment are unnecessary and impracticable, and good cause exists for adopting these special conditions 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 opportunity for comment described above.
Start List of Subjects Start Printed Page 37019
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 Diamond Aircraft Industries DA-42 airplane.
a. For diesel engine installations, the engine mounts and supporting structure must be designed to withstand the following:
(a) The effects of sudden engine stoppage may alternatively be mitigated to an acceptable level by utilization of isolators, dampers clutches, and similar provisions, so unacceptable load levels are not imposed on the previously certificated structure.
b. The limit engine torque to be considered under § 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 used, it must be shown that the limit torque imposed on the engine mount is consistent with the provisions of § 23.361(c). In other words, it must be shown that the use of the factors listed in § 23.361(c)(3) will result in limit torques on the mount that are equivalent to or less than those imposed by a conventional gasoline reciprocating engine.
a. Each diesel engine installation must be constructed and arranged to result in vibration characteristics that—
(2) Do not exceed vibration characteristics that a previously certificated airframe structure has been approved for —
(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.
a. 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.
b. Methods of compliance that are acceptable for turbine engine fuel systems requirements of § 23.951(c) are also considered acceptable for this requirement.
a. 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.
b. The fuel system must be in an operational configuration that will yield the most adverse, that is, conservative results.
c. 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.
a. The electrical system must comply with the following requirements:
(1) 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.
(2) 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.
(3) There must be the ability to separate the FADEC power supply (alternator) from the battery and from the remaining electrical system.
(4) In case of loss of alternator power, the installation must guarantee the battery will provide the power for an appropriate time after appropriate warning to the pilot. This period must be at least 30 minutes required, 60 minutes desired.
(5) FADEC, alternator, and battery must be interconnected in an appropriate way so, in case of loss of battery power, the supply of the FADEC is guaranteed by the alternator.
8. Equipment—General—Powerplant Instruments (Compliance with § 23.1305 and 91.205 requirements):
a. In place of compliance with § 23.1305, the applicant will comply with the following:
(1) The following are required powerplant instruments:
(d) A tachometer indicating propeller speed. Start Printed Page 37020
1. 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.
b. In place of compliance with § 91.205, the following will be complied with: The diesel engine has no manifold pressure gauge as required by § 91.205, in its place, the engine instrumentation as installed is to be approved as equivalent. TCDS is to be modified to show power indication will be accepted to be equivalent to the manifold pressure indication.
The minimum fuel designation (for diesel engines) must be established so it is not less than that required for the operation of the engines within the limitations in paragraphs (b) and (c) of § 23.1521.
a. Fuel filler openings must be marked at or near the filler cover with—
(1) For diesel engine-powered airplanes—
a. 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.
b. 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).
a. Vibration levels throughout the engine operating range must be evaluated and:
(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; 23.629 (or CAR 3.159, as applicable to various models); 23.572; 23.573; 23.574 and 23.901.
b. Vibration levels imposed on the airframe can be mitigated to an acceptable level by use of isolators, dampers clutches, and similar provisions, so unacceptable vibration levels are not imposed on the previously certificated structure.
a. 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,
b. 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 the engine in the event of a catastrophic engine failure; or
c. It must be shown that all possible liberated engine parts or components do not have adequate energy to penetrate engine cowlings; or
d. 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.
Issued in Kansas City, Missouri on June 22, 2005.
[FR Doc. 05-12720 Filed 6-27-05; 8:45 am]