[Federal Register Volume 71, Number 143 (Wednesday, July 26, 2006)]
[Rules and Regulations]
[Pages 42251-42254]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-11878]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 23

[Docket No. CE248, Special Conditions No. 23-188-SC]


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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final special conditions.

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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.

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.

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

[[Page 42252]]

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 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 
Sec.  23.1309 provisions to the Full Authority Digital Engine Control 
(FADEC).

Type Certification Basis

    Under the provisions of Sec.  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, Sec. Sec.  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 Sec. Sec.  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 Sec.  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, Sec.  21.115 noise certification requirements 
of 14 CFR part 36.
    Special conditions, as appropriate, as defined in 11.19, are issued 
in accordance with Sec.  11.38, and become part of the type 
certification basis in accordance with Sec.  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 Sec.  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 Sec.  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.

List of Subjects in 14 CFR Part 23

    Aircraft, Aviation safety, Signs and symbols.

[[Page 42253]]

Citation

0
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.

The Special Conditions

0
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.
    1. Engine torque (Provisions similar to Sec.  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, Sec.  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 Sec.  23.361(c), that is, it must be shown that the 
utilization of the factors listed in Sec.  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 Sec.  
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 Sec.  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 [deg]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 Sec.  23.951(c) are also considered acceptable 
for this requirement.
    4. Powerplant--Fuel System--Fuel system hot weather operation 
(Compliance with Sec.  23.961 requirements):
    In place of compliance with Sec.  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 [deg]F, -0[deg], 
+5[deg] 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 Sec.  23.973(f) requirements):
    In place of compliance with Sec.  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 Sec.  
23.977 requirements):
    In place of compliance with Sec.  23.977(a)(1) the applicant will 
comply with Sec.  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 Sec.  23.1165 requirements):
    Considering that the FADEC provides the same function as an 
ignition system for this diesel engine, in place of compliance to Sec.  
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 
Sec.  23.1305 requirements):
    In place of compliance with Sec.  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 Sec.  23.1337(b).
    (b) An oil pressure indicator.
    (c) An oil temperature indicator.
    (d) A tachometer indicating propeller speed.
    (e) A coolant temperature indicator.

[[Page 42254]]

    (f) An indicating means for the fuel strainer or filter required by 
Sec.  23.997 to indicate the occurrence of contamination of the 
strainer or filter before it reaches the capacity established in 
accordance with Sec.  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 Sec.  23.1521(d) 
requirements):
    Instead of compliance with Sec.  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 
Sec.  23.1521.
    10. Markings And Placards--Miscellaneous markings and placards--
Fuel, oil, and coolant filler openings (Compliance with Sec.  
23.1557(c)(1) requirements):
    Instead of compliance with Sec.  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, Sec. Sec.  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.

    Issued in Kansas City, Missouri, on July 19, 2006.
John R. Colomy,
Acting Manager, Small Airplane Directorate, Aircraft Certification 
Service.
 [FR Doc. E6-11878 Filed 7-25-06; 8:45 am]
BILLING CODE 4910-13-P