Despite the impressive looking inventory, Bulgaria's fighter force in January 1941 consisted of only 91 machines, with just 18 of them modern Bf 109E monoplanes. A further 11 were outdated PZL.24B fighters, and the remainder were Avia B.534 biplanes. The ground-based air defenses were made up of only 8 and 6 AA guns. To help its new ally the 12th Army of the Wehrmacht offered support with its aircraft and air defence assets and provided 8 Freya-type radars dispersed throughout the country. A dispersed observation and reporting system was gradually developed.