examples of minor changes are included in the list which follows this paragraph. These changes may be approved by the applicant's appropriately authorized DER. An acceptable method of handling these changes includes submitting to FAA the engineering design change notices, where necessary, to fully describe the changes.
Intervals between submittal of each new change, or group of changes, should not exceed six months. Consideration should be given to the possibility that, while certain design changes may well be considered minor when evaluated singly, the cumulative influence of a number of such changes may have an adverse effect, and may have to be evaluated as major changes. The following is a list of typical minor changes:
(1) Slight variations in clearances.
(2) Reasonable increase in radius of fillets.
Increase in thickness, where the design permits it, without adverse effects.
(4) Change to equivalent, or improved material, in minor parts.
(5) Improvements in heat treatments of parts, without reducing elongation of parts subjected to high stress.
(6) Small changes in the design of non-critical parts of the engine.
(7) Improvements in the manufacturing, or processing of parts, without reducing the material properties.
Major Changes. Section 21.97 applies to the approval of major changes in the type design. To substantiate major changes to a certificated engine, substantiating data must be submitted.
Typical examples of major changes are included in the list which follows this paragraph. Acceptable substantiating data include, type certificate older may paply for amenant of he orge at a type certificate for major changes. As provided in FAR Part 21, Subpart E, applicants other than the type certificate holder may apply for a supplemental type certificate for major changes, when appropriate. The applicant should meet at least the minimum airworthiness standards applicable to the original engine, when qualifying design changes. when an unsafe condition has developed, special substantiation may be required to demonstrate that the unsafe condition has been overcome by the proposed type design change. Changes that will contribute to improved safety are often developed as a result of service experience, and may be approved as constituting the current type design standard in compliance with Section 21.99(b). Major changes may be Chap 2 22 Par 13
recommended for approval by the type certificate holder's appropriately designated DER, but may not be introduced into service use until approved by the FAA. The following is a list of typical major changes:
(1) A change of either compression ratio, or supercharger gear ratio.
(2) Establishing the eligibility of engines for either an increase of a temperature limit, or a speed limit, such as: oil inlet temperature, turbine inlet or exhaust gas temperature, cylinder base or head temperature, fan engine minimum idle speed, or power turbine maximum speed.
(3) A change in the material or design of highly stressed parts; either rotating, reciprocating, or non-rotating; likely to adversely affect the airworthiness of such parts.
(4) A change involving the method of clamping or attaching rotating, reciprocating, or non-rotating parts.
(5) Any change that measurably affects the engine's fit, function, or compatibility with existing aircraft installations, such as those defined in the preceding paragraph 10b.
(6) Any change to a life-limited part leading to a change of approved life.
(7) Any change providing corrective action for Airworthiness Directives (ADs).
14. IDENTIFICATION PLATE. (FAR Part 33 and Part 45, Subpart B).
a. General. An acceptable method of complying with the fireproof and location requirements of Section 45.11(a) is to meet the following conditions:
(1) The data thereon is legible after the application of a 2,000 °F flame, for at least 15 minutes.
(2) The plate is located in an accessible place on the engine and engine modules for easy viewing, and is not expected to be easily defaced or dislodged.
b. Identification Data. The type of information to be included on the identification plate, and the persons authorized to install and remove identification plates, are prescribed in Section 45.13.
c. Identification Plate Attachment. AC 43-17,iMethods, Techniques, and Practices Acceptable to the Administrator Governing the Installation, Removal, or Change of Identification Chap 2 Par 13 23
Data and Identification Plates, dated September 5, 1979, is incorporated herein. Compliance with Section 33.19 must be shown, in that the means of attaching the identification plate will not cause cracks, induce fluid leaks, or be susceptible to dislodgement within the interior of the engine, or otherwise adversely affect the engine and module durability, or introduce design features shown to be hazardous or unreliable.
Chap 2 24 Par 14
CHAPTER 3. TYPE CERTIFICATION GUIDANCE MATERIAL SECTION 1. SUBPART A--GENERAL
15. Section 33.3, General.
Section 33.3 General:
Each applicant must show that the aircraft engine concerned meets the applicable requirements of this part.
*** Guidance: The INTENT of this section is self-evident.
Incorporations: None.
References: None.
Generally speaking, FAA will approve an applicant's engine within those conditions and limits which are satisfactorily substantiated. The applicant's assumed data and information for the specific engine design, for which type certification is requested, are initially (in part) provided to FAA with submittal of the application for TC. . FAA then, and throughout the TC process, evaluates and validates the assumptions by analyses and The conclusions result in statements of ratings, operating limitations, and instructions for continued airworthiness, installing, and operating the engine - all to assure sate operation of the engine in service.
16. Section 33.4, Instructions for Continued Airworthiness.
Section 33.4 Instructions for Continued Airworthiness.
The applicant must prepare Instructions for Continued Airworthiness in accordance with Appendix A to this Part [immediately following] that are acceptable to the Administrator. The instructions may be incomplete at type certification if a program exists to ensure their completion prior to delivery of the first aircraft with the engine installed, or upon issuance of a standard certificate of airworthiness for the aircraft with the engine installed, whichever occurs later.
APPENDIX A TO PART 33 -- INSTRUCTIONS FOR CONTINUED
AIRWORTHINESS A33.1 GENERAL
(a) This Appendix specifies requirements for the preparation of Instructions for Continued Airworthiness as required by Section 33.4.
Chap 3 Par 15 25
The Instructions for Continued Airworthiness for each engine must include the Instructions for Continued Airworthiness for all engine parts. If Instructions for Continued Airworthiness are not supplied by the engine part manutacturer for an engine part, the Instructions for Continued Airworthiness for the engine must include the information essential to the continued airworthiness of the engine.
The applicant must submit to the FAA a program to show how changes to the Instructions for Continued Airworthiness made by the applicant or by the manufacturers of engine parts will be distributed.
A33.2 FORMAT
(a) The Instructions for Continued Airworthiness must be in the form of a manual or manuals as appropriate for the quantity of data to be provided.
The format of the manual or manuals must provide for a practical arrangement.
A33.3 CONTENT The contents of the manual or manuals must be prepared in the English language. The Instructions for Continued Airworthiness must contain the following manuals or sections as appropriate, and information:
(a) Engine Maintenance Manual or Section.
(1) explanation of the engine's features and data to the extent necessary for maintenance or preventive maintenance.
(2) A detailed description of the engine and its components, systems, and installations.
(3) Installation instructions, including proper procedures for uncrating, deinhibiting, acceptance checking, lifting, and attaching accessories, with any necessary checks.
(4) Basic control and operating information describing how the engine components, systems, and installations operate, and information describing the methods of starting, running, testing, and stopping the engine and its parts including any special procedures and limitations that apply.
(5) Servicing information that covers details regarding servicing points, capacities of tanks, reservoirs, types of fluids to be used, pressures applicable to the various systems, locations of lubrication points, lubricants to be used, and equipment required for servicing.
Chap 3 26 Par 16
Scheduling information for each part of the engine that provides the recommended periods at which it should be cleaned, inspected, adjusted, tested, and lubricated, and the degree of inspection, the applicable wear tolerances, and work recommended at these periods.
However, the applicant may refer to an accessory, instrument, or equipment manufacturer as the source of this information if the applicant shows that the item has an exceptionally high degree of complexity requiring specialized maintenance techniques, test equipment, or expertise. The recommended overhaul periods and necessary cross references to the Airworthiness Limitations section of the manual must also be included. In addition, applicant must include an inspection program that includes the frequency of the inspections necessary to provide for the continued airworthiness of the engine.
(7) Troubleshooting information describing probable malfunctions, how to recognize those malfunctions, and the remedial action for those malfunctions.
(8) Information describing the order and method of removing the enqine and its parts and replacing parts, with any necessary precautions to be taken. Instructions for proper ground handling, crating. and shipping must
(9) A list of the tools and equipment necessary for maintenance and directions as to their method of use.
(b) Engine Overhaul Manual or Section.
(1) Disassembly information including the order and method of disassembly for overhaul.
Cleaning and inspection instructions that cover the material and apparatus to be used and methods and precautions to be taken during overhaul. overhaul inspection must also be included. fits and clearances relovant to Methods of overhaul.
Details of repair methods for worn or otherwise substandard parts and components along with the information necessary to determine when replacement is necessary.
The order and method of assembly at overhaul.
Instructions for testing after overhaul.
(7) Instructions for storage preparation, including any storage limits.
(8) A list of tools needed for overhaul.
A33.4 AIRWORTHINESS LIMITATIONS SECTION The Instructions for Continued Airworthiness must contain a section titled Airworthiness Limitations that is segregated and clearly distinguishable from the rest of the document. This section must set forth each mandatory replacement time, inspection interval, and related Chap 3 Par 16 27
procedure required for type certification. If the Instructions for Continued Airworthiness consist of multiple documents, the section required by this paragraph must be included in the principal manual. This section must contain a legible statement in a prominent location that reads: 'The Airworthiness Limitations Section is FAA approved and specifies maintenance required under Sections
43.16 and 91.163 of the Federal Aviation Regulations unless an alternative program has been FAA approved."
*** Guidance: The INTENT of this section is to assure that Instructions for Continued Airworthiness are available prior to service introduction of the engine.
Incorporations: None.
References: None.
The overhaul section, or manual portion of the instructions for continued airworthiness, may not be available at time of type certification of the engine. In such cases, the engine TCDS should incorporate a "NOTE" prohibiting the overhaul of engines until the overhaul instructions are available; and that, meanwhile, the manufacturer may provide rebuilt engines utilizing new engine tolerances. Overhauled engines must deliver, at least, the IC rated powers, or thrusts, within the ratings' associated limitations.
17. Section 33.5, Instruction Manual for Installing and Operating the Engine.
Section 33.5 Instruction manual for installing and operating the engine.
Each applicant must prepare and make available to the Administrator prior to the issuance of the type certificate, and to the owner at the time of delivery of the engine, approved instructions for installing and operating the engine. The instructions must include at least the following:
(a) Installation instructions.
(1) The location of engine mounting attachments, the method of attaching the engine to the aircraft, and the maximum allowable load for the mounting attachments and related structure.
The location and description of engine connections to be attached to accessories, pipes, wires, cables, ducts, and cowling.
(3) An outline drawing of the engine including overall dimensions.
Chap 3 28 Par 16
(b) Operation Instructions.
(1) The operating limitations established by the Administrator.
(2) The power or thrust ratings and procedures for correcting for nonstandard atmosphere.
(3) The recommended procedures, under normal and extreme ambient conditions for--
(i) Starting;
(11) Operating on the ground; and
(iii) Operating during flight.
*** Guidance: The INTENT of this section is to assure that the engine installation and operating instructions are approved by the time the type certificate for the engine is issued.
Incorporations: None.
References: SAE Document ARP 1507, 'Helicopter Engine/Airframe Interface Document and Checklist," issued September 1985. This reference offers further guidance on the types and formats of engine installations and operations information. Although this document is oriented to helicopter (turboshaft) engines, it may be useful as additional general guidance to authors of installation and operating instruction manuals.
a. The installation and operating instructions should incorporate all relevant and complete information on the characteristics, performance, and physical interfaces of the engine. A type certificated engine may include some external lines, equipment mountings, diaphragms, or firewalls which do not meet all certification requirements of some installations. Added line shrouding, relocation of fluid lines, or other changes constitute engine type design changes which may be required for the aircraft installation. Such FAA-approved changes are accomplished preferably by the engine type certificate holder, as approval based on engine compatibility and endurance qualification is usually necessary. However, upon achieving satisfactory coordination with the engine type certificate holder, accomplishment of such changes by the aircraft applicant is often acceptable as an alternative.
b. The engine type certificate holder or applicant may elect to incorporate items of equipment or accessories which are oftentimes handled as part of the aircraft installation responsibility. Examples of such items are engine mounted oil tanks, oil coolers, fuel heaters, generators, thrust reversers, and exhaust nozzles, and various fluid pumps.
(1) When the engine manufacturer elects to furnish such accessories, it is basically implied that he will substantiate Chap 3 Par 17 29
them for engine compatibility, and be responsible for dealing with service difficulties.
(2) If the engine type certificate holder elects to establish aircraft installation compliance, he should develop and provide the necessary installation data in accordance with applicable aircraft requirements.
(3) If the engine type certification effort incorporates findings of compliance for aircraft installation items (i.e., to FAR Part 23, 25, 27, or 29 requirements) then such should be identified on the engine TCDS.
c. The engine installation instructions should incorporate information on the means of limiting, and on the quality of engine compressor bleed air availabie for airtrame use. Design bleed air quality, limit (s), and the means of limiting should be verified by the failure modes and effects analysis and by testing, as appropriate. An example of the need for such information is seen in the certification of FAR Part 23 turbine powered aircraft:
Turbine engine bleed air systems of turbine powered airplanes must pe investigated to determine that, ii the bleed air system is usec for direct cabin pressurization, it is not possible for hazardous contamination of the cabin air system to occur in the event of lubrication system failure.
d. The engine installation instructions should incorporate statements of instrumentation types, ranges, required precision, and accuracies for those engine parameters required for safe operation. These statements should be based upon the applicantselected ratings for the specific engine design, as verified and substantiated throughout the type certification process, particularly the block tests.
18. Section 33.7, Engine Ratings and Operating Limitations.
Section 33.7 Engine ratings and operating limitations.
(a) Engine ratings and operating limitations are established by the Administrator and included in the engine certificate data sheet specified in Section 21.41 of this chapter, including ratings and limitations based on the operating conditions and information specified in this section, as applicable, and any other information found necessary for safe operation of the engine.
For reciprocating engines, ratings and operating limitations are established relating to the following:
(!) Horsepower or torque, r.p.m., manifold pressure, and time at critical pressure altitude and sea level pressure altitude for-- Chap 3 30 Par 17
(i) Rated maximum continuous power (relating to unsupercharged operation or to operation in each supercharger mode as applicable); and
(ii) Rated takeoff power (relating to unsupercharged operation or to operation in each supercharger mode as applicable).
Fuel grade or specification.
(3) Oil grade or specification.
Temperature of the-- Cylinder;
(ii) Oil at the oil inlet; and
(iii) Turbosupercharger turbine wheel inlet gas.
(5) Pressure of--
(i) Fuel at the fuel inlet; and
(ii) Oil at the main oil gallery.
Accessory drive torque and overhang moment.
Component life.
Turbosupercharger turbine wheel I.p.m.
For turbine engines, ratings and operating limitations are established relating to the following:
(1) Horsepower, torque, or thrust, r.p.m., gas temperature, and time for--
(i) Rated maximum continuous power or thrust (augmented) ;
(ii) Rated maximum continuous power or thrust (unaugmented) ;
(iii) Rated takeoff power or thrust (augmented);
(iv) Rated takeoff power or thrust (unaugmented);
Rated 30 Minute OEI power;
Rated 2-1/2 Minute OEI power;
(vii) Rated Continuous OE1 power; and
(viii) Auxiliary power unit (APU) mode of operation.
(2) Fuel designation or specification.
(3) Oil grade or specification.
(4) Hydraulic fluid specification.
Temperature of--
(i) Oil at a location specified by the applicant;
Induction air at the inlet face of a supersonic engine, including steady state operation and transient over-temperature and time allowed;
(iii) Hydraulic fluid of a supersonic engine;
Fuel at a location specified by the applicant;
and (V) External surfaces of the engine; if specified by the applicant.
(6) Pressure of--
(i) Fuel at the fuel inlet;
(ii) Oil at a location specified by the applicant;
(iii) Induction air at the inlet face of a supersonic engine, including steady state operation and transient overpressure and time allowed; and
(iv) Hydraulic fluid.
Chap 3 Par 18 31
(7) Accessory drive torque and overhang moment.
(8) Component life.
(9) Fuel filtration.
(10) Oil filtration.
(11) Bleed air.
(12) The number of start-stop stress cycles approved for each rotor disc and spacer.
(13) Inlet air distortion at the engine inlet.
(14) Transient rotor shaft overspeed r.p.m., and number of overspeed occurrences.
(15) Transient gas overtemperature, and number of overtemperature occurrences.
(16) For engines to be used in supersonic aircraft engine rotor windmilling rotational r.p.m.
*** Guidance: The INTENT of this section is to publicly document the engine ratings and limitations data and other information necessary for safe operation of the engine.
Incorporations: AC 91-33A, Use of Alternate Grades of Aviation Gasoline for Grade 80/87 and Use of Automotive Gasoline, dated July 1984.
References:
1. RTCA Document DO-160B.
2. SAE Committee Report No. AE4EL.
July i, 1982. AC 21-6A, "Production Under Type Certificate Only", dated
4. AC 21-1B, "Production Certificate", dated May 10 1976.
operating limitations. the various rated powers and thrusts, and the maximum and minimum Tests. Specific block tests are conducted to establish The effects of altitude on engine ratings and operating limitations should be determined acceptably. This may be accomplished by means of altitude chamber testing, flight testing, simulated altitude testing, or analytical data using proven methodology.
(2) The ratings' limiting maximum operating parameters should be qualified by operation as indicated in the 150-hour FAA endurance test. Other limitations may be qualified by testing in which the limiting values may be the average attained for appropriate durations.
Chap 3 32 Par 18
(3) Special or additional tests may be necessary, at times, to qualify some limitations for either complex engines, such as turbine engines with several rotor systems when limiting test conditions cannot be easily maintained for all rotors simultaneously, or where limits for components may be tested separately on rig tests. Specific examples are:
(1) Under certain ambient conditions, it may not be possible to simultaneously exercise to its respective speed limitation, each rotor of a multiple rotor engine during endurance test running. In such a case, and if approved by the cognizant FAA project manager or engineer, the test may be replicated as necessary to demonstrate each respective limitation, as also discussed under the "Section 33.87, Endurance Test" paragraph of this AC.
Engine electronic control devices such as full authority digital electronic controls (FADECs), require substantiation of tolerance to the effects of lightning strikes.
This substantiation is interpreted to be necessary under the general requirements of FAR Section 33.91(a). Current practice is to require an installations simulation of the complete enginefurnished FADEC system, including cables and connectors, to be subjected to direct and induced lightning strike tests. This effort is typically conducted in accordance with the guidance information provided in References 1 and 2 above. The primary expected outcomes of this testing are definition of the lightning energy levels which the FADEC system can tolerate without adverse affects, and the level of shielding or other protection which the airframer will need to provide upon installation of the FADEC system in the aircraft.
(4) Military test data and reports may be used for certification purposes, if they are determined by the FAA type certification project manager or engineer to satisfy the criteria of the appropriate FAR Part 33 section, and of the conformity
b. Ratings and Limitations. Rated engine powers and thrusts are usually established on the basis of engine operation on a test stand, in its normal operating configuration; but usually with, at least, a test stand inlet in place of the aircraft installation hardware.
(1) Ratings are included on the engine TCDS.
(2) All operating limitations that may be considered by the applicant to affect flight safety, if exceeded, are to be noted in the model description and should include such items as the maximum values of: Engine pressure ratio (EPR); torque;
rotorspeeds; powers; gas path temperatures; component temperatures; manifold pressure; vibration levels; fuel and Chap 3 Par 18 33