Imperial units commonly used units for length are (li), (tseung/cheung), (tsek/chek), (tsun/chun), (fen/fan) in descending scale order. These units are now rarely used in daily life, the imperial and metric systems being preferred. The imperial equivalents are written with the same basic Chinese characters as the Chinese system. In order to distinguish between the units of the two systems, the units can be prefixed with "Ying" () for the Imperial system and "Wa" () for the Chinese system. In writing, derived characters are often used, with an additional (mouth) radical to the left of the original Chinese character, for writing imperial units.
Imperial Airways "Castor" for Imperial Airways' Empires Air Routes, in 1937. In November 2016, 80 years later, the Crete2Cape Vintage Air Rally flew this old route with fifteen vintage aeroplanes - a celebration of the skill and determination of these early aviators. Imperial Airways operated many types of aircraft from its formation on 1 April 1924 until 1 April 1940 when all aircraft still in service were transferred to BOAC. Imperial Airways Imperial Airways was the early British commercial long-range airline, operating from 1924 to 1939 and serving parts of Europe but principally the British Empire routes to South Africa, India and