This SAE Aerospace Information Report (AIR) has been compiled to provide information on hydraulic systems fitted to commercial aircraft. Data has been provided for the following aircraft types: a. Wide body jet airliners; b. Narrow body jet airliners; c. Turboprop/commuter aircraft; d. Business jet aircraft The airliners that have been included in this document are generally in operational service with either airlines or cargo operators. Information on aircraft that have been retired from in-service use has been included for reference purposes. No information is presented for aircraft that are currently being developed.