Question to the Ministry of Defence:

To ask His Majesty's Government what evaluation they have made of the use of MIL-PRF-23699 lubricants in Royal Air Force and Royal Navy jet-powered aircraft; and of its potential benefits in reducing hazards for those exposed to engine oil or engine oil decomposition products.

MIL-PRF-23699 is a specification for jet engine lubricants against which numerous individual products are manufactured by different suppliers. Although no overall assessment has been made of lubricants manufactured to this specification, hazard assessments are made against the specific products used within Royal Air Force and Royal Navy air systems jet engines. The Control of Substances Hazardous to Health (COSHH) regulations require Original Equipment Manufacturers to provide Safety Data Sheets for all supplied products, including lubricants, which inform the hazard assessment process. Where residual risks are identified, they are relayed to the air system operator alongside any associated warnings and recommended mitigations.