This section of the FEDERAL REGISTER

contains notices to the public of the proposed

issuance of rules and regulations. The

purpose of these notices is to give interested

persons an opportunity to participate in the

rule making prior to the adoption of the final

rules.

Proposed Rules Federal Register

67860

Vol. 69, No. 224

Monday, November 22, 2004

DEPARTMENT OF TRANSPORTATION 

Federal Aviation Administration 

14 CFR Part 23

[Docket No. CE214; Notice No. 23–04–02–

SC] 

Special Conditions: Thielert Aircraft 

Engines GmbH, Cessna Model 172 

Series; Diesel Cycle Engine Using 

Turbine (Jet) Fuel

AGENCY: Federal Aviation 

Administration (FAA), DOT.

ACTION: Notice of proposed special 

conditions. 

SUMMARY: This proposes special 

conditions for the Cessna 172 series 

airplane. This airplane, as modified by 

Thielert Aircraft Engines GmbH, 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 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 exiting 

airworthiness standards.

DATES: Comments must be received on 

or before December 22, 2004.

ADDRESSES: Comments on this proposal 

may be mailed in duplicate to: Federal 

Aviation Administration, Regional 

Counsel, ACE–7, Attention: Rules 

Docket, Docket No. CE214, 901 Locust, 

Room 506, Kansas City, Missouri 64106, 

or delivered in duplicate to the Regional 

Counsel at the above address. 

Comments must be marked: CE214. 

Comments may be inspected in the 

Rules Docket weekdays, except Federal 

holidays, between 7:30 a.m. and 4 p.m.

FOR FURTHER INFORMATION CONTACT: Pete 

Rouse, Federal Aviation Administration, 

Aircraft Certification Service, Small 

Airplane Directorate, ACE–111, 901 

Locust, Kansas City, Missouri, 816–329–

4135, 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 notice 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 CE214.’’ The postcard 

will be date stamped and returned to the 

commenter.

Background 

On February 11, 2002, Thielert 

Aircraft Engines GmbH, of Lichtenstein, 

Germany applied for a supplemental 

type certificate to install a diesel cycle 

engine utilizing turbine (jet) fuel in the 

Cessna Model 172. The Cessna Model 

172, currently approved under Type 

Certificate No. 3A12 is a four-place, 

high wing, fixed tricycle landing gear, 

conventional planform airplane. The 

Cessna 172 airplanes to be modified 

have gross weights in the range of 2300 

to 2558 pounds in the normal category. 

The affected series of airplanes have 

been equipped with various gasoline 

reciprocating engines of 160 to 180 

horsepower. 

In anticipation of the reintroduction 

of diesel engine technology into the 

small airplane fleet, the FAA issued 

Policy Statement PS–ACE100–2002–004 

on May 15, 2003, 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 

elevated for applicability to diesel 

engine installations. These concerns are 

not considered universally aplicable to 

all types of possible diesel engines and 

diesel engine installations. However, 

after review of the Thielert installation, 

the Thielert 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, 

Thielert Aircraft Engines GmbH must 

show that the Cessna Model 172, as 

changed, continues to meet the 

applicable provisions of the regulations 

incorporated by reference in Type 

Certificate No. 3A13 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. 3A13 are as follows: 

The certification basis of models 

172K, 172L, 172M, 172N, and 172P is: 

Part 3 of the Civil Air Regulations 

effective November 1, 1949, as amended 

by 3–1 through 3–12. In addition, 

effective S/N 17271035 and on, 14 CFR 

part 23, § 23.1559, effective March 1, 

1978. 14 CFR part 36, dated December 

1, 1969, plus Amendments 36–1 

through 36–5 for Model 172N; 14 CFR 

part 36, dated December 1, 1969, plus 

Amendments 36–1 through 36–12 for 

Model 172P through 172Q. In addition, 

effective S/N 17276260 and on, 14 CFR 

Federal Register / Vol. 69, No. 224 / Monday, November 22, 2004 / Proposed Rules 67861

part 23, § 23.1545(a), Amendment 23–

23, dated December 1, 1978, including:

Equivalent Safety Items for: 

Airspeed Indicator—CAR 3.757

Operating Limitations—CAR 3.778(a)

The certification basis for the model 

172R is: 

Part 23 of the Federal Aviation 

Regulations effective February 1, 1965, 

as amended by 23–1 through 23–6, 

eccept as follows: 

14 CFR part 23, §§ 23.423; 23.611; 

23.619; 23.623; 23.689; 23.775; 23.871; 

23.1323; and 23.1563, as amended by 

Amendment 23–7. 14 CFR part 23, 

§§ 23.807 and 23.1524, as amended by 

Amendment 23–10. 14 CFR part 23, 

§§ 23.507; 23.771; 23.853(a), (b) and (c); 

and 23.1365, as amended by 

Amendment 23–14. 14 CFR part 23, 

§ 23.951, as amended by Amendment 

23–15. 14 CFR part 23, §§ 23.607; 

23.675; 23.685; 23.733; 23.787; 23.1309 

and 23.1322, as amended by 

Amendment 23–17. 14 CFR part 23, 

§ 23.1301, as amended by Amendment 

23–20. 14 CFR part 23, §§ 23.1353; and 

23.1559, as amended by Amendment 

23–21. 14 CFR part 23, §§ 23.603; 

23.605; 23.613; 23.1329 and 23.1545, as 

amended by Amendment 23–23. 14 CFR 

part 23, §§ 23.441 and 23.1549, as 

amended by Amendment 23–28. 14 CFR 

part 23, §§ 23.779 and 23.781, as 

amended by Amendment 23–33. 14 CFR 

part 23, §§ 23.1; 23.51 and 23.561, as 

amended by Amendment 23–34. 14 CFR 

part 23, §§ 23.301; 23.331; 23.351; 

23.427; 23.677; 23.701; 23.735; and 

23.831, as amended by Amendment 23–

42. 14 CFR part 23, §§ 23.961; 23.1093; 

23.1143(g); 23.1147(b); 23.1303; 

23.1357; 23.1361 and 23.1385, as 

amended by Amendment 23–43. 14 CFR 

part 23.562(a), 23.562(b)2, 23.562(c)1, 

23.562(c)2, 23.562(c)3, and 23.562(c)4, 

as amended by Amendment 23–44. 14 

CFR part 23, §§ 23.33; 23.53; 23.305; 

23.321; 23.485; 23.621; 23.655 and 

23.731, as amended by Amendment 23–

45; and 14 CFR part 36, dated December 

1, 1969, as amended by Amendments 

36–1 through 36–21.

Equivalent Safety Items for: 

Induction System Icing Protection—

14 CFR 23.1093

Throttle Control—14 CFR 23.1143(g) 

Mixture Control—14 CFR 23.1147(b)

The type certification basis for the 

modified airplanes is as stated 

previously with the following 

modifications: The certification basis for 

the model 172S is: 

Part 23 of the Federal Aviation 

Regulations effective February 1, 1965, 

as amended by 23–1 through 23–6, 

except as follows: 

14 CFR part 23, §§ 23.423; 23.611; 

23.619; 23.623; 23.689; 23.775; 23.871; 

23.1323; and 23.1563, as amended by 

Amendment 23–7. 14 CFR part 23, 

§§ 23.807 and 23.1524, as amended by 

Amendment 23–10. 14 CFR part 23, 

§§ 23.507; 23.771; 23.853(a), (b) and (c); 

and 23.1365, as amended by 

Amendment 23–14. 14 CFR part 23, 

§ 23.951, as amended by Amendment 

23–15. 14 CFR part 23, §§ 23.607; 

23.675; 23.685; 23.733; 23.787; 23.1309 

and 23.1322, as amended by 

Amendment 23–17. 14 CFR part 23, 

§ 23.1301, as amended by Amendment 

23–20. 14 CFR part 23, §§ 23.1353 and 

23.1559, as amended by Amendment 

23–21. 14 CFR part 23, §§ 23.603; 

23.605; 23.613; 23.1329 and 23.1545, as 

amended by Amendment 23–23. 14 CFR 

part 23, §§ 23.441 and 23.1549, as 

amended by Amendment 23–28. 14 CFR 

part 23, §§ 23.779 and 23.781, as 

amended by Amendment 23–33. 14 CFR 

part §§ 23.1; 23.51 and 23.561, as 

amended by Amendment 23–34. 14 CFR 

part 23, §§ 23.301; 23.331; 23.351; 

23.427; 23.677; 23.701; 23.735; and 

23.831, as amended by Amendment 23–

42. 14 CFR part 23, §§ 23.961; 23.1093; 

23.1143(g); 23.1147(b); 23.1303; 

23.1357; 23.1361 and 23.1385, as 

amended by Amendment 23–43. 14 CFR 

part 23, §§ 23.562(a); 23.562(b)2; 

23.562(c)1; 23.562(c)2; 23.562(c)3; and 

23.562(c)4, as amended by Amendment 

23–42. 14 CFR part 23, §§ 23.961; 

23.1093; 23.1143(g); 23.1147(b); 

23.1303; 23.1357; 23.1361 and 23.1385, 

as amended by Amendment 23–43. 14 

CFR part 23, §§ 23.562(a); 23.562(b)2; 

23.562(c)1; 23.562(c)2; 23.562(c)3; and 

23.562(c)4, as amended by Amendment 

23–44. 14 CFR part 23, §§ 23.33; 23.53; 

23.305; 23.321; 23.485; 23.621; 23.655 

and 23.731, as amended by Amendment 

23–45.

14 CFR part 36, dated December 1, 

1969, as amended by Amendments 36–

1 through 36–21.

Equivalent Safety Items for: 

Induction System Icing Protection—

14 CFR 23.1093

Throttle Control—14 CFR 23.1143(g) 

Mixture Control—14 CFR 23.1147(b)

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; 23.363; 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; 23.629; (at 

Amendment 23–6 for Cessna 172 

models R and S; Civil Aviation 

Regulation 3.159 applies to all other 

models); 23.773; 23.777; 23.777(d); 

23.779; 23.779(d); 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; 23.991; 23.993; 23.994; 

23.995; 23.997; 23.997(a)(2), in place of 

§§ 23.997(a)(1); 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; 23.1309; 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; 23.1527; 23.1529; 23.1541; 

23.1543; 23.1549; 23.1551; 23.1555; 

23.1557; 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—23.1061

Ignition switches—23.1145

The type certification basis includes 

exemption, 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 

Cessna Model 172 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 Cessna Model 172 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 

67862 Federal Register / Vol. 69, No. 224 / Monday, November 22, 2004 / Proposed Rules 

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 Cessna Model 172 will 

incorporate the following novel or 

unusual design features: The Cessna 

Model 172, as modified by Thielert 

Aircraft Engines GmbH, will incorporate 

an aircraft diesel engine utilizing 

turbine (jet) fuel. 

Applicability 

As dicussed above, these special 

conditions are applicable to the Cessna 

Model 172. Should Thielert Aircraft 

Engines GmbH apply at a later date for 

a supplemental type certificate to 

modify any other model included on 

Type Certificate No. 3A13 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 one model 

series 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 21.101; and 14 CFR 

11.38 and 11.19. 

Discussion 

The major concerns identified in the 

development of FAA policy deal with 

the installation of the diesel engine and 

its vibration levels under normal 

operating conditions and with one 

cylinder inoperative, the 

accommodation of turbine fuels in 

airplane systems that have generally 

evolved based on gasoline requirements, 

the anticipated use of a FADEC to 

control the engine, and the appropriate 

limitations and indications for a diesel 

engine powered airplane. The general 

concerns associated with the Thielert 

modification 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; and do 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, was added. 

Fuel and Fuel System Related 

Requirements: Due to the use of turbine 

fuel, this airplane must comply with the 

requirements in § 23.951(c). 

Section 23.961 will be complied with 

using the turbine fuel requirements. 

These requirements will be 

substantiated by flight-testing as 

described in Advisory Circular AC 23–

8B, Flight Test Guide for Certification of 

Part 23 Airplanes. 

This special condition specifically 

requires testing to show compliance to 

§ 23.961 and adds the possibility of 

testing non-aviation diesel fuels. 

To ensure fuel system compatability 

and reduce the possibility of misfueling, 

and discounting the first clause of 

§ 23.973(f) referring to turbine engines, 

the applicant will comply with 

§ 23.973(f). 

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. 

Due to the use of turbine fuel, the 

applicant will comply with 

§ 23.1305(c)(8). 

Due to the use of turbine fuel, the 

applicant must comply with 

§ 23.1557(c)(1)(ii). Section 

23.1557(c)(1)(ii) will not apply. 

‘‘Turbine engine’’ is interpreted to mean 

‘‘aircraft diesel engine’’ for this 

requirement. 

FADEC and Electrical System 

Requirements: The electrical system 

must comply with the following: 

• 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. 

• The transition from the actual 

engine net (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. 

• There must be the ability to 

separate the FADEC power supply 

(alternator) from the battery and from 

the remaining electrical system. 

• 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. 

• FADEC, alternator and battery must 

be interconnected in an appropriate 

way, so that in case of loss of battery 

power, the supply of the FADEC is 

guaranteed by the alternator. 

Limitations and Indications: 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 the following:

(1) Power setting, in percentage, and 

(2) Fuel temperature. 

Due to the use of turbine fuel, the 

requirements for § 23.1521(d), as 

applicable to fuel designation for 

turbine engines, will apply. 

The Proposed Special Conditions 

Accordingly, the Federal Aviation 

Administration (FAA) proposes the 

following special conditions as part of 

the type certification basis for Cessna 

Model 172 airplanes modified by 

Thielert Aircraft Engines GmbH. 

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: 

Federal Register / Vol. 69, No. 224 / Monday, November 22, 2004 / Proposed Rules 67863

(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 for 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) and (a)(2), the applicant 

will comply with the following: 

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 

changes. 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 of 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. 

(d) A coolant temperature indicator. 

(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–

67864 Federal Register / Vol. 69, No. 224 / Monday, November 22, 2004 / Proposed Rules 

5007D and provisions for replacing the 

fuel filter at this specified period (or a 

shorter period) are included in the 

maintenance scheduled 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), 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—FuelFreezing 

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 coldsoaked 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; 23.629 (or CAR 3.159, as 

applicable to various models); 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. Powerful 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 become 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 nonintegral block designs. The following is 

required. 

(1) It must be shown that the engine 

construction type (massive or integral 

block with nonremovable 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.

Issued in Kansas City, Missouri, on 

November 1, 2004. 

James E. Jackson, 

Acting Manager, Small Airplane Directorate, 

Aircraft Certification Service.

[FR Doc. 04–25697 Filed 11–19–04; 8:45 am] 

BILLING CODE 4910–13–M

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration 

14 CFR Part 39 

[Docket No. FAA–2004–19444; Directorate 

Identifier 2004–CE–33–AD] 

RIN 2120–AA64 

Airworthiness Directives; Pacific 

Aerospace Corporation, Ltd. Model 

750XL Airplanes

AGENCY: Federal Aviation 

Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking 

(NPRM). 

SUMMARY: The FAA proposes to adopt a 

new airworthiness directive (AD) for all 

Pacific Aerospace Corporation, Ltd. 

(Pacific Aerospace) Model 750XL 

airplanes. This proposed AD would 

require you to replace any type TLP–D 

or TLED rivets on the aileron pushrod 

ends and elevator control pushrod ends. 

This proposed AD results from 

mandatory continuing airworthiness 

information (MCAI) issued by the 

airworthiness authority for New 

Zealand. We are issuing this proposed 

AD to replace the above identified rivets 

on the aileron pushrod ends and 

elevator control pushrod ends, which, if 

not replaced, could result in loose 

mechanical elements in the control 

systems. This could lead to control 

anomalies and loss of airplane control.

DATES: We must receive any comments 

on this proposed AD by December 27, 

2004.

ADDRESSES: Use one of the following to 

submit comments on this proposed AD: 

• DOT Docket Web site: Go to

http://dms.dot.gov and follow the