AeroShell Fluid 1 is now AeroShell Turbine Oil 3

Aeroshell is withdrawing AeroShell Fluid 1 (ASF 1) as of now, replacing it with AeroShell Turbine Oil 3 (ASTO 3), both products are the same, manufactured by Shell at the same facility.  They were originally approved and packed differently to meet two different UK Defence Standards (DEF STAN):

AeroShell Fluid 1 was approved to UK Defence Standard (DEF STAN) 91-44; a general purpose light lubricating and preserving oil, NATO CODE 0-134, Joint Service Designation OM-13.

AeroShell Turbine Oil 3 is approved to DEF STAN 91-99; a mineral based gas turbine lubricating oil with anti-corrosion additives NATO Code 0-135, Joint Service Designation OM-11.

The DEF STAN states that ASTO 3 may be used as an alternative to ASF 1, but ASF 1 must not be used as an alternative to ASTO 3.

Reason for withdrawal The United Kingdom Ministry of Defence (MoD) has made the DEF STAN 91-44 obsolete and it is superseded by DEF STAN 91-99.

ASF 1 and ASTO 3 are the same products and fully interchangeable therefore Shell is now withdrawing ASF 1. The new labels on ASTO 3 packaging will display that it is an alternative for ASF 1. The label will also include a reference to the current DEF STAN 91-99 and the obsolete DEF STAN 91-44. 

Distributors and users of ASF 1 should place orders for ASTO 3 as an alternative for ASF 1 and amend the necessary documentation in their order books and manuals.

From April 2016 AeroShell are changing the labels of AeroShell Turbine Oil 3 to reflect that ASTO 3 is an alternative for ASF 1 displaying the specification DEF STAN 91-99 and DEF STAN 91-44 (obsolete).