maximum altitude of . BEA's first-ever internal German flight took to the air in September 1946 when one of its DC-3s departed Hamburg Fuhlsbüttel for RAF Gatow in Berlin. During the 1948–49 Berlin Airlift, BEA co-ordinated the operations of the 25 British airlines that participated in the Airlift's Operation Plainfare. On 8 July 1951, BEA transferred its operations from Gatow to Tempelhof, thereby concentrating all West Berlin air services at Berlin's city centre airport. BEA's move to Tempelhof resulted in a significant increase in passenger numbers due to the removal of Allied restrictions on the carriage of local civilians on commercial airline services from/to West Berlin and Tempelhof's central location. This enabled the airline to expand its Berlin-based fleet to six Douglas DC-3s. During the early-to-mid-1950s, BEA leased in aircraft that were bigger than its Tempelhof-based fleet of DC-3/Pionair, Viking and Elizabethan piston-engined airliners from other operators to boost capacity, following a steady increase in the airline's passenger loads. (BEA continued to augment its Berlin fleet with additional aircraft leased from other airlines on an ad hoc basis. This included an ex-Transair Vickers Viscount 700 belonging to its newly formed independent rival British United Airways, which was damaged beyond repair on 30 October 1961 in a non-fatal landing accident at Frankfurt Rhein-Main Airport at the end of a passenger flight that had originated at Tempelhof.) In 1958, BEA began replacing its ageing piston airliners with Vickers Viscount 701 turboprop aircraft in a high-density, 63-seat single class seating arrangement. Up to 10 new Vickers Viscount 802s, which featured a more spacious, 66-seat single-class seating arrangement, soon replaced the older series 701 aircraft. The greater range and higher cruising speed of the 802 series enabled BEA to inaugurate a non-stop London Heathrow – Berlin Tempelhof service on 1 November 1965. By 1964, BEA operated up to 20,000 flights each year from and to Berlin. These represented approximately half of the airline's total yearly flights to/from Germany and generated profits of £1 million per year. 22 January 1966 marked the first appearance of a British trijet at Tempelhof when Hawker Siddeley flew in its HS 121 Trident 1E demonstrator aircraft for evaluation by BEA. A week later, on 29 January, BEA began evaluating the BAC One-Eleven's suitability for its Berlin operations, with the start of a series of test flights conducted on its behalf by BAC's 475 series demonstrator. This included a number