Commonly referred to as the 'Viper' by its aircrew, the F-16has provided the US Air Force with its air defence capabilityfor the last twenty-six years. The aircraft is a major export success and is in service with the air forces of Turkey, Israel, Belgium, Denmark, Netherlands, Norway, South Korea, and Singapore. It has been steadily developed and improved and is availablearmed with a wide varietyof combat systems for both air defence and ground attack missions.