Prefects had three cockpits. All the RAF machines were two-seat navigational training aircraft without the third cockpit installed. Avro 637: Armed patrol version of the Avro 626. Pilot had a .303 in (7.7 mm) Vickers machine gun mounted on the fuselage while the observer/gunner was armed with a .303 in (7.7 mm) Lewis Gun on an Avro low-drag mounting. This variant featured a slightly larger wingspan with rounded wingtips. Eight aircraft were sold to the Kwangsi Air Force (Government of South China) in China. Tatra T.126: Licence built 626, manufactured in Czechoslovakia; two versions proposed: one with 355 hp (265 kW) Avia Rk. 17 and export version for Turkey and the Balkans with a 260 hp (190 kW) Armstrong Siddeley Cheetah V. Only one built, possibly never flown because of the Munich crisis - factory was in the territory occupied by Germany. Operators 198 Avro 626s and Prefects were produced. Army Aviation Service received 15 aircraft. Austrian Air Force received seven aircraft. Belgian Air Force received 12 aircraft, two of which were still in service at the time of the German invasion in 1940. Brazilian Air Force received 16 aircraft. Royal Canadian Air Force received 12 aircraft. RCAF machines featured cold weather cowlings, enclosed cockpits and skis. They survived until early in the Second World War. 3 Squadron RCAF 111 squadron RCAF Chinese Nationalist Air Force - Probably received 13, certainly 11. May have built one itself. All served in the Second Sino-Japanese War. Chilean Air Force received 20 aircraft. Czechoslovak Air Force received one aircraft. Tatra under licence manufactured only one because of the Munich crisis. Royal Egyptian Air Force received 27 machines, their first military aircraft, as distinct from DH-60 Moths. Only 25 served, as two were lost in delivery and replaced Egyptian 626s served from 1933 until 1944. Estonian Air Force received four aircraft. Hellenic Air Force received 21 aircraft which were in service at the time of the Italian invasion. Three machines escaped the fall of Greece to join the RAF in the desert. Irish Air Corps received four aircraft, which served until 1941. Lithuanian Air Force received three aircraft in 1937-1939. The type was still in service at the time of the Soviet invasion and occupation. Royal New Zealand Air Force received four Lynx-engined but three-cockpit Prefect aircraft for the RNZAF in 1935. No 1 Flying Training School. Portuguese Air Force and Portuguese Navy received