Boeing and Airbus standardize
Generally two types of airframe greases have been used in Airbus and and Boeing aircraft, clay based and lithium based. Due to the superior performance of lithium complex grease over clay based grease, Airbus and Boeing are now switching to lithium.
No need to worry about accidentally mixing clay and lithium as happened in the loss of Alaska Flight 261.
One grease replaces many.
Improved water wash out capability.
Improved high temperature performance.
Standardized product over a wide range of aircraft.
Boeing begin researching for a new generation of general purpose airframe grease with improved performance and one that could be used in the widest possible range of grease applications. The end result is Boeing specification BMS 3-33.
The applicable military specification MIL-PRF-23827C has been modified. The new spec is:
MIL-PRF-23827C Type I for lithium base grease
MIL-PRF-23827C Type II for clay base grease
Airbus specification AIMS 009-06-001 led to the development of a new lithium soap thickened grease to solve lockout problems on flaps and slat mechanism.
The combined approach of Boeing and Airbus to develop a single specification based on new grease technology will improve performance and make the mechanic's job easier.
Boeing and Airbus testing has shown how Lithium complex grease for general airframe use outperforms other greases. Currently, the following greases Boeing BMS 3-33
AeroShell Grease 7 Boeing BMS 3-33 and MIL-PRF-23827C Type I
NYCO Grease GN 144 Airbus AIMS 09-06-001 and Service Letter 27-094 Rev. 4
Royco 27 MIL-PRF-23827C Type I
Operators of other aircraft are advised that Type I and Type II are not compatible (read NTSB accident report on Flight 261). Many grease containers as of this date do not yet specify Type I or Type II. Standardization to Type II will prevent accidental mixing of grease and improve performance.
AeroShell Grease 7 is an advanced multi-purpose grease,
composed of a synthetic oil thickened with Microgel®, possessing
good load carrying ability over a wide temperature range. It is
inhibited against corrosion and has excellent resistance to water.
The useful operating temperature range is –73°C to +149°C.