The civilian Lancastrian and maritime reconnaissance Shackleton were derived from the successful Lancaster design. The Tudor was a pressurised but problematic post-war Avro airliner which faced strong competition from designs by Bristol, Canadair, Douglas, Handley Page, and Lockheed. With the same wings and engines as the Lincoln, it achieved only a short (34 completed) production run following a first flight in June 1945 and the cancellation of an order from BOAC. The older Avro York was somewhat more successful in both the RAF and in commercial service, being distinguished by a fuselage square in cross-section. Both Tudors and Yorks played an important humanitarian part in the Berlin Airlift.