Question: The Derwitzer Glider was a glider that was developed by Otto Lilienthal, a German pioneer of aviation who became known as the "flying man", and on which date, his glider stalled and he was unable to regain control?
Context: Take Flight is a musical with book by John Weidman, music by David Shire and lyrics by Richard Maltby, Jr..  The musical is inspired by the early history of aviation, interweaving the lives of the Wright Brothers, Charles Lindbergh, Amelia Earhart and her publisher George Putnam, along with such sundry luminaries as Otto Lilienthal, the German "Glider King"; Commander Richard Byrd; French flying aces Nungesser and Coli, and various others. The Otto Lilienthal Museum in Anklam (Germany) is a museum about the "glider king" Otto Lilienthal, the flight pioneer, as well as a pioneer in technical, social and cultural projects. Berlin Tegel "Otto Lilienthal" Airport (German: "Flughafen Tegel "Otto Lilienthal"" ) (IATA: TXL, ICAO: EDDT) is the main international airport of Berlin, the federal capital of Germany.  It formerly served West Berlin.  The airport is named after Otto Lilienthal and is the fourth busiest airport in Germany with just over 20.7 million passengers in 2014.  The airport is a hub for Air Berlin and serves as a base for Germanwings.  It features flights to several European metropolitan and leisure destinations as well as some intercontinental routes. The Derwitzer Glider was a glider that was developed by Otto Lilienthal, so named because it was tested near Derwitz in Brandenburg.  When flown in 1891, it became his a very early successful design able to carry a person and the one of the first successful manned aircraft in the world.  He made flights of up to 25 metres (80 feet) in it. The Lilienthal "Normalsegelapparat" ( German: "Normal soaring apparatus") is a glider designed by Otto Lilienthal in Germany in the late 19th century.  It is considered to be the first aeroplane to be serially produced, examples being made between 1893 and 1896. Gustav Lilienthal (October 9, 1849 – February 1, 1933) was a German social reformer, a pioneer in building and construction technology (Prefabricated buildings), inventor of different Construction sets (e. g. Anchor Stone Blocks) and involved in the pioneering work of his brother, Otto Lilienthal in aviation. Lilienthal Gliding Medal – the highest soaring award in the world, established by Fédération Aéronautique Internationale (FAI) in 1938 in honor of Otto Lilienthal, a German pioneer of human aviation.  It aims "to reward a particularly remarkable performance in gliding, or eminent services to the sport of gliding over a long period of time".  The award is made at the annual FAI General Conference.  Medal was designed by Austrian artist Josef Humplik. Lilienthal Glacier ( ) is a glacier flowing west into Cayley Glacier between Pilcher Peak and Baldwin Peak, on the west coast of Graham Land, Antarctica.  It was photographed by the Falkland Islands and Dependencies Aerial Survey Expedition in 1956–57, and mapped from these photos by the Falkland Islands Dependencies Survey.  It was named by the UK Antarctic Place-Names Committee in 1960 for Otto Lilienthal, a German pioneer of flight in gliders. Jan Wnęk (1828 – 10 July 1869) was a Polish carver of religious statues who is claimed to have constructed and flown a glider (aircraft) in the 1860s, predating the flights of Otto Lilienthal.  There is a speculative "reconstruction" of Wnek's glider in the Kraków Museum of Ethnography. Otto Lilienthal (23 May 1848 – 10 August 1896) was a German pioneer of aviation who became known as the "flying man".  He was the first person to make well-documented, repeated, successful flights with unpowered airplanes.  Newspapers and magazines published photographs of Lilienthal gliding, favorably influencing public and scientific opinion about the possibility of flying machines becoming practical.  On 9 August 1896, his glider stalled and he was unable to regain control.  Falling from about 15 m (50 ft), he broke his neck and died the next day, 10 August 1896.
Answer: 9 August 1896