aircraft circular letter
51SOS — is the commonly used description for the international Morse code distress signal (· · · · · ·). This distress signal was first adopted by the German government in radio regulations effective April 1, 1905, and became the worldwide standard when… …
52Science and invention in Birmingham — Birmingham is the second largest city in the United Kingdom. It is one of the country s principal industrial centres and has an impressive history of industrial and scientific innovation.16th century1547: Although no record is kept to indicate… …
53Concorde — For other uses, see Concorde (disambiguation). Concorde Role Supersonic airliner …
54Western use of the Swastika in the early 20th century — adopted the symbol in the 1920s, it continued in use in Western countries with its original meaning until the Nazi association became dominant in the 1930s. The term swastika is first attested in English in 1871, and first refers to the Nazi… …
55airplane — /air playn /, n. 1. a heavier than air aircraft kept aloft by the upward thrust exerted by the passing air on its fixed wings and driven by propellers, jet propulsion, etc. 2. any similar heavier than air aircraft, as a glider or helicopter. Also …
56United Nations — 1. an international organization, with headquarters in New York City, formed to promote international peace, security, and cooperation under the terms of the charter signed by 51 founding countries in San Francisco in 1945. Abbr.: UN Cf. General… …
57Messerschmitt Bf 109 variants — Main article: Messerschmitt Bf 109 Bf 109 Bf 109G 10, with Erla Haube canopy and taller, wooden vertical fin/rudd …
58Level crossing — This article is about at grade intersections between railway and road. For where two rail lines cross, see level junction. For a type of nuclear receptor (RXR), see Retinoid X receptor. A level crossing at Chertsey, England, as the barriers rise …
59Scale model — A scale model of the Tower of London. This model can be found inside the tower …
60'Allo 'Allo! (series 5) — This article contains episode listings for the fifth series of the British Sitcom series Allo Allo!. The series contains twenty six episodes which first aired between 3 September 1988 and 25 February 1989. Series 5 is longer than any of the other …
