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This SAE Aerospace Recommended Practice (ARP) identifies and defines methods of compliance with power available and inlet distortion requirements for rotorcraft with inlet barrier filter (IBF) installations. The material developed herein is intended to provide industry-recommended methods of compliance with civil airworthiness regulations. It is intended to serve as a basis for new or revised FAA advisory material describing acceptable methods for determining power assurance, establishing power available, and for substantiating acceptable engine inlet distortion for IBF installations. The ARP does not address other types of inlet protection systems such as inertial separator, electrostatic precipitators, or foreign object debris (FOD) screens.

The purpose of this SAE Aerospace Information Report (AIR) is to disseminate qualitative information regarding foreign object debris (FOD) damage to the gas path of rotorcraft gas turbine engines and to discuss methods of FOD prevention. Although turbine-powered fixed-wing aircraft are also subject to FOD, the unique ability of the rotorcraft to hover above, takeoff from, and land on unprepared surfaces creates a special need for a separate treatment of this subject.

This aerospace Information Report (AIR) aims to provide a comprehensive understanding of Synthesized Power Indicators (SPI) and their application in the aviation industry. The report delves into the philosophy behind SPI, including its benefits and limitations. It explores various industry use cases and provide insights into the implementation of SPI in rotorcrafts. Additionally, the report focuses on certification and compliance considerations, outlining the requirements and standards that must be met for SPI incorporation. This document will serve as a valuable resource for aerospace professionals seeking guidance on SPI integration and certification processes.

This SAE Aerospace Information Report (AIR) defines the helicopter bleed air requirements which may be obtained through compressor extraction and is intended as a guide to engine designers.

This SAE Aerospace Information Report (AIR) describes the different aspects of corrosion on helicopter powerplants, on the components that are affected, and the subsequent consequences on the helicopter, engine durability, performance, and dependability. Guidelines that minimize corrosion during the design stage and during service operation are also discussed.

This ARP applies to turbine engines that are to be used in helicopters. It provides the engine designer guide lines in achieving a satisfactory turbine engine drive shaft connection.

This SAE Aerospace Information Report (AIR) defines helicopter turboshaft engine power assurance theory and methods. Several inflight power assurance example procedures are presented. These procedures vary from a very simple method used on some normal category civil helicopters, to the more complex methods involving trend monitoring and rolling average techniques. The latter method can be used by small operators but is generally better suited to the larger operator with computerized maintenance record capability.

The purpose of this SAE Aerospace Information Report (AIR) is to illustrate the effect of installation power losses on the performance of a helicopter. Installation power losses result from a variety of sources, some associated directly with the basic engine installation, and some coming from the installation of specific items of aircraft mission specific equipment. Close attention must be paid to the accurate measurement of these losses so that the correct aircraft performance is calculated. Installation power losses inevitably result in a reduction in the overall performance of the aircraft. In some cases, careful attention to detail will allow specific elements of the overall loss to be reduced with immediate benefit for the mission performance of the aircraft. When considering items of equipment that affect the engine, it is important to understand the effect these will have on overall aircraft performance to ensure that mission capability is not unduly compromised.

A general method for the preliminary design of a single, straight-sided, low subsonic ejector is presented. The method is based on the information presented in References 1, 2, 3, and 4, and utilizes analytical and empirical data for the sizing of the ejector mixing duct diameter and flow length. The low subsonic restriction applies because compressibility effects were not included in the development of the basic design equations. The equations are restricted to applications where Mach numbers within the ejector primary or secondary flow paths are equal to or less than 0.3.

The purpose of this document is to define the power spectrum during normal and emergency operations of a twin engine helicopter and thereby to postulate suitable power plant rating structures. The document does not address the power requirements for single engine helicopters or those with more than two engines.

This Aerospace Information Report deals with protection of helicopter aircraft engines against erosion. Applicability is restricted to aircraft having a disc loading of less than 15 pounds per square foot.

This SAE Aerospace Recommended Practice (ARP) provides a guide for the preparation of a helicopter engine/airframe interface document and checklist. This document and checklist should identify the information needed by the engine manufacturer and the aircraft manufacturer to integrate the engine design with the aircraft design and either provide this information or give reference to where this information is located. The intent is to assure that the engine manufacturer and the airframe manufacturer identify and make provision for this information so it can be easily accessible to either manufacturer as needed in the development stages of an engine-airframe integration project.

This SAE Aerospace Information Report (AIR) identifies Propulsion EngineerÕs recommendations for the instrumentation that is required for the safe operation and maintenance of turbine engines as installed in helicopters. It should be used as a guide for cockpit layout, as well as a reference for maintenance considerations throughout the propulsion area. Propulsion instruments should receive attention early in the design phase of the helicopter. Maintenance and diagnostics recorders are not considered within the scope of this document. (See ARP1587, "Aircraft Gas Turbine Engine Monitoring System Guide".)

The purpose of this standard is to provide a method of evaluating helicopter fuel economy which accounts for the significant technical variables in helicopter and powerplant design.

The purpose of this recommended practice is to establish a standard format for the presentation of helicopter mission data, which will provide data required to establish airframe and/or engine component life.

Turbine engines installed in helicopters require a highly sophisticated oil system to fulfill two tasks: a. Cooling/oil supply b. Lubrication. While lubrication is an engine internal procedure, cooling and oil supply require more or less design activity on the aircraft side of the engine/airframe interface for proper engine function, depending on the engine type. The necessity for engine cooling and oil supply provisions on the airframe can lead to interface problems because the helicopter manufacturer can influence engine related functions due to the design of corresponding oil system components. This SAE Aerospace Information Report (AIR) deals with integration of engine oil systems with the airframe and gives information for both helicopter and engine manufacturers for a better understanding of interface requirements.

This SAE Aerospace Recommended Practice (ARP) identifies and defines a method of measuring those factors affecting installed power available for helicopter powerplants. These factors are installation losses, accessory power extraction, and operational effects. Accurate determination of these factors is vital in the calculation of helicopter performance as described in the RFM. It is intended that the methods presented herein prescribe and define each factor as well as an approach to measuring said factor. Only basic installations of turboshaft engines in helicopters are considered. Although the methods described may apply in principle to other configurations that lead to more complex installation losses, such as an inlet particle separator, inlet barrier filter (with or without a bypass system), or infrared suppressor, specialized or individual techniques may be required in these cases for the determination and definition of engine installation losses.

Turbine engines installed in rotorcraft have an exhaust system that is designed and produced by the aircraft manufacturer. The primary function of the exhaust system is to direct hot exhaust gases away from the airframe. The exhaust system may consist of a tailpipe, which is attached to the engine, and an exhaust fairing, which is part of the rotorcraft. The engine manufacturer specifies a baseline "referee" tailpipe design, and guaranteed engine performance is based upon the use of the referee tailpipe and tailpipe exit diameter. The configuration used on the rotocraft may differ from the referee tailpipe, but it is intended to minimize additional losses attributed to the installation. This Aerospace Recommended Practice (ARP) describes the physical, functional, and performance interfaces to be considered in the design of the aircraft exhaust system.

This SAE Aerospace Information Report (AIR) outlines a recommended procedure for evaluation of the vibration environment to which the gas turbine engine powerplant is subjected in the helicopter installation. This analysis of engine vibration is normally demonstrated on a one-time basis upon initial certification, or after a major modification, of an engine/helicopter configuration. This AIR deals with linear vibration as measured on the basic case structure of the engine and not, for example, torsional vibration in drive shafting or vibration of a component within the engine such as a compressor or turbine airfoil. In summary, this AIR discusses the engine manufacturer’s "Installation Test Code" aspects of engine vibration and proposes an appropriate measurement method.

This SAE Aerospace Recommended Practice (ARP) recommends a methodology to be used for the design, analysis and test evaluation of modern helicopter gas turbine propulsion system stability and transient response characteristics. This methodology utilizes the computational power of modern digital computers to more thoroughly analyze, simulate and bench-test the helicopter engine/rotor system speed control loop over the flight envelope. This up-front work results in significantly less effort expended during flight test and delivers a more effective system into service. The methodology presented herein is recommended for modern digital electronic propulsion control systems and also for traditional analog and hydromechanical systems.