Our maintenance shop recently dug into which AeroShell hydraulic fluids and greases are appropriate to use for maintaining a 1984 Piper Malibu PA46-310P. The latest version of the Piper Maintenance Manual for this aircraft, p/n 761-783, has a list of acceptable fluids and greases shown in section 12-20-00: MIL-G-7711, MIL-G-23827, MIL-G-81322, MIL-H-5606, and MIL-L-7870.

These military specs in the past defined specific greases and hydraulic fluids for use in aircraft maintenance. The standards are also quite old and all of them have been replaced with newer specs that no longer define a specific product, but provide for a performance standard that manufacturers of newer products have to meet in order to gain approval.


Superseded by MIL-PRF-81322, Revision G on 24 Jan 2005.

AeroShell Grease #22 meets or exceeds the MIL-PRF-81322G standard.


Superseded by MIL-PRF-23827, Revision C, Amendment 2, on 29 Sep 2006.

AeroShell Grease #33 meets or exceeds the MIL-PRF-23827C standard.


Superseded by MIL-PRF-81322, Revision G, on 24 Jan 2005.

AeroShell Grease #22 meets or exceeds the MIL-PRF-81322G standard.


Superseded by MIL-PRF-83282, Revision D, Amendment 1, on 10 Dec 1997.

AeroShell Fluid #31 is a synthetic base stock that meets or exceeds the MIL-PRF-83282D standard. AeroShell Fluid #41 is a petroleum base stock that only meets the obsolete MIL-PRF-5606J standard. As it is based on a petroleum base stock, AeroShell Fluid #41 does not meet the newer MIL-PRF-83282D standard that requires a synthetic base. MIL-PRF-83282D also replaces MIL-PRF-5606J. Even though AeroShell Fluid #31 and AeroShell Fluid #41 are compatible with each other, but we do not recommend mixing them.


Superseded by MIL-PRF-7870, Revision E, on 05 Nov 2015.

AeroShell Fluid #3 meets or exceeds the MIL-PRF-7870E standard, but is no longer in production. We are searching for a suitable replacement.