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The test method describes the procedure for determination of the total acid number (TAN) of new and degraded polyol ester and diester-based gas turbine lubricants by the potentiometric titration technique. The method was validated to cover an acidity range of 0.05 to 6.0 mg KOH g-1. The method may also be suitable for the determination of acidities outside of this range and for other classes of lubricants.

This method is used for determining the compatibility of a candidate lubricant with specific reference lubricants. The reference lubricants to be used will typically be mandated by the owner of the product specification against which the candidate lubricant is being compared. This method is split into two procedures (Procedure A and Procedure B) with a summary of each procedure contained in Section 4.

The intent of this SAE Aerospace Information Report (AIR) is to summarize and review the E34 committee’s efforts to educate the aerospace propulsion lubrication community on the science of micropitting, its consequences, and the various tribology evaluation methods that can be employed under aviation related conditions to differentiate formulation related aggravating factors.

The test method describes the procedure for the direct determination of water concentration in polyol ester and diester based aerospace lubricants by commercially available automated coulometric Karl Fischer titration instruments. The method was validated to cover the water concentration range of 150 to 3500 µg/g. The method may also be suitable for the determination of water concentrations outside this range and for other classes of fluids; however, the precision statement shall not be applicable for such uses.

This SAE Aerospace Information Report (AIR) establishes guidance for the specification of formulated lubricant properties which contribute to the lubricating function in bearings, gears, clutches, and seals of aviation propulsion and drive systems.

There has been a recent upsurge in interest from the media concerning the quality of the environment within aircraft cabins and cockpits especially in the commercial world. This has included (although by no means been limited to) the air quality, with particular reference to the alleged effects of contamination from the aircraft turbine lubricant. Possible exposure to 'organophosphates' (OPs) from the oil has raised special concerns from cabin crew. Such is the concern that government organisations around the world, including Australia, USA and UK, have set up committees to investigate the cabin air quality issue. Concern was also voiced in the aviation lubricants world at the way in which OP additives in turbine lubricants were being blamed in some reports for the symptoms being experienced by air crew and passengers. SAE Committee E-34 therefore decided that it should gather as much available information on the subject as possible.

An oil sample is placed into an open top glass vial which is then inserted into a stainless steel pressure vessel. The vessel is then sealed, pressurized, and placed into a heated aluminum block bath for 18 hours. At the end of the 18 hour time period, the vessel is removed from the heat source and allowed to cool to room temperature at which time the contents of the vial are filtered and the total sediment is reported as milligrams of sediment per 20 mL of oil.

This AIR describes the current scientific and engineering principles of gas turbine lubricant performance testing per AS5780 and identifies gaps in our understanding of the technology to help the continuous improvement of this specification.

The intent is to provide a reference which explains the types of possible changes to AS5780 products and provide appropriate context to the QPG. All product change requests to the QPG will be evaluated on their merits recognizing the content of this AIR is guidance only.

This SAE Aerospace Information Report (AIR) establishes guidance for the specification of formulated lubricant properties which contribute to the lubricating function in bearings, gears, clutches, and seals of aviation propulsion and drive systems.

Employing ‘ball-on-cylinder’ philosophy, a non-rotating steel ball is held in a vertically mounted chuck and using an applied load is forced against an axially mounted steel cylinder. The test cylinder is rotated at a fixed speed while being partially immersed in a lubricant reservoir. This maintains the cylinder in a wet condition and continuously transports a lubricating film of test fluid to the ball and cylinder interface. The diameter of the wear scar generated on the test ball is used as a measure of the fluid’s lubricating properties. The apparatus can be used, by adjusting the operating conditions, to reproduce two different wear mechanisms; mild and severe wear, the ALTE therefore has the ability to assess a lubricant’s performance in that regard.

This specification defines basic physical, chemical, and performance limits for 5 cSt grades of gas turbine engine lubricating oils used in aero and aero-derived marine and industrial applications, along with standard test methods and requirements for laboratories performing them. It also defines the quality control requirements to assure batch conformance and materials traceability, and the procedures to manage and communicate changes in oil formulation and brand. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to the PRI at the address in Appendix D Section D.2, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by the PRI. Additional tests and evaluations may be required by individual equipment builders before an oil is approved for use in their equipment.

This specification defines basic physical, chemical, and performance limits for 5 cSt grades of gas turbine engine lubricating oils used in aero and aero-derived marine and industrial applications, along with standard test methods and requirements for laboratories performing them. It also defines the quality control requirements to assure batch conformance and materials traceability, and the procedures to manage and communicate changes in oil formulation and brand. This specification invokes the Performance Review Institute (PRI) product qualification process. Requests for submittal information may be made to the PRI at the address in Appendix D Section D.2, referencing this specification. Products qualified to this specification are listed on a Qualified Products List (QPL) managed by the PRI. Additional tests and evaluations may be required by individual equipment builders before an oil is approved for use in their equipment.

The lubricant performance capability for aero propulsion drive systems is derived from the physical properties of the oil and performance attributes associated with the chemical properties of the oil. Physical properties, such as viscosity, pressure-viscosity coefficient and full-film traction coefficient are inherent properties of the lubricating fluid. Chemical attributes are critical for the formation of protective boundary lubricating films on the surfaces to prevent wear and scuffing. These attributes are also associated with surface initiated fatigue (micropitting). To assure performance and to provide required information for engineering design, methodology for at least five oil properties are being studied: (1) pressure-viscosity coefficient, (2) full-film traction coefficient, (3) scuffing resistance, (4) wear resistance; and (5) micropitting propensity.

There has been a recent upsurge in interest from the media concerning the quality of the environment within aircraft cabins and cockpits especially in the commercial world1-4. This has included (although by no means been limited to) the air quality, with particular reference to the alleged effects of contamination from the aircraft turbine lubricant. Possible exposure to ‘organophosphates’ (OPs) from the oil has raised special concerns from cabin crew. Such is the concern that government organisations around the world, including Australia, USA and UK, have set up committees to investigate the cabin air quality issue. Concern was also voiced in the aviation lubricants world at the way in which OP additives in turbine lubricants were being blamed in some reports for the symptoms being experienced by air crew and passengers. SAE Committee E-34 therefore decided that it should gather as much available information on the subject as possible.

The test method describes the procedure for the direct determination of water concentration in polyol ester and diester based aerospace lubricants by the commercially available automated coulometric Karl Fischer titration instrument. The method was validated to cover the water concentration range of 150 to 3500 µg/g. The method may also be suitable for the determination of water concentrations outside this range and for other classes of fluids, however, the precision statement shall not be applicable for such uses.

To present methods which, according to the consensus of the aviation propulsion community represented by SAE Committee E-34, allow the continued assessment of load carrying capacity of current chemistry products during periods of limited or nonavailability of previously used standardized methods.

This specification covers a neopentyl polyol ester fluid (see 8.2) with AS5780 HPC or MIL-PRF-23699 HTS Class performance.

This SAE Aerospace Recommended Practice (ARP) is intended to evaluate corrosion inhibiting properties of synthetic gas turbine lubricants and gearbox oils.

This AIR describes the current scientific and engineering principles of gas turbine lubricant performance testing per AS5780 and identifies gaps in our understanding of the technology to help the continuous improvement of this specification.