Turbine engine oils (TEO) used in commercial aircraft and general aviation engines are conforming with the US military specification MIL-PRF-23699 (formerly MIL-L-23699), an essential step in the process of gaining engine equipment manufacturer approval in different engine, engine accessories and auxiliary power unit types. Although primarily a military specification, MIL-PRF-23699 has served the commercial aviation sector since the 1960s and still used today. This specification covers four oil categories:
STD – Standard
HTS – High Thermal Stability
C/I – Corrosion Inhibited (for military use only). Oils in this category include AeroShell Turbine Oil 531, Eastman Aero-D, NYCO TURBONYCOIL 601 and Castrol AeroJet 5.
EE – Enhanced Ester
In the case of TEOs, hotter running engines with extended times between overhauls are not adequately covered by MIL-PRF-23699 for the type of oil needed in modern commercial engines requiring additionaly tighter controls
In 2005, SAE (Society of Automotive Engineers) has issued SAE AS5780 to replace MIL-PRF-23699 defining two grades of oil:
SPC – Standard Performance Capability, almost identical to STD except for additional reporting items.
HPC – High Performance Capability. SAE HPC grade has more stringent performance requirements compared with the MIL-PRF-23699 HTS grade.
Most commonly used aircraft turbine engine oil brands fall under both MIL-PRF-23699 and SAE AS5780 specifications in the respective categories.
- STD/SPC: Castrol 500 (*),AeroShell 500, AeroShell 560,Mobil Jet II, etc.
- HTS/HPC: Mobil Jet Oil 254, Eastman 2197, etc.
Furthermore, certain oils comply with different specifications to those of MIL-PRF-23699 or SAE AS5780.
For additional information on differences between MIL-PRF-23699 and SAE AS5780 specifications please consult the supplied documentation.
Most of these oils are listed in our Web Platform for Supplies and can be supplied to customers in different packing options, due to our extensive co-operations with their respective producers or distributors. If your oil is not listed please contact us for assistance or a quotation.
Note: HTS/HPC oils offer improved temperature capabilities (engine cleanliness) but at the cost of lower elastomer compatibility & higher prices. Most engines run well on STD/SPC oils.
(*) Castrol™ 5000 Aircraft Synthetic Turbine Oil is replaced by other 5 centistoke gas turbine oils in the MIL-PRF-23699 STD category. Please consult supplied TDS.