Question: What event was the plane that was powered by the WS-15 engine revealed at?

Context paragraphs:
BMW M12: The BMW M12/13 turbo 1500 cc 4-cylinder turbocharged Formula One engine, based on the standard BMW M10 engine introduced in 1961, powered the F1 cars of Brabham, Arrows and Benetton.  Nelson Piquet won the FIA Formula One Drivers' Championship in 1983 driving a Brabham powered by the BMW M12/13 turbo.  It was the first Drivers' Championship to be won using a turbocharged engine.  The engine also powered the BMW GTP and in the 2.0 liter naturally aspirated form, the successful March Engineering Formula Two cars.

Xian WS-15: The WS-15 (), codename Emei, is a Chinese afterburning turbofan engine designed by the Shenyang Aeroengine Research Institute and manufactured by the Xi'an Aero-Engine Corporation, used to power China's Chengdu J-20 fighter, which would be able to achieve supercruise.

British Airways Flight 268: British Airways Flight 268 was a regularly scheduled flight from Los Angeles LAX airport to London Heathrow LHR.  The flight took off at about 9:24 p.m. on 20 February 2005.  When the plane, a four engine Boeing 747–436, was around 300 feet into the air, flames burst out of its number 2 engine, a result of engine surge.  The pilots shut the engine down.  Air traffic control expected the plane to return to the airport and deleted the flight plan.  However, after consulting with the airline dispatcher, the pilots decided to set off on their flight plan "and get as far as we can" rather than dump 70 tonnes of fuel and land.  The 747 is certified to fly on three engines.  Having reached the East Coast, the assessment was that the plane could continue safely.  The cross-Atlantic journey encountered less favourable conditions than predicted.  Upon reaching the UK, believing there to be insufficient usable fuel to reach their destination, the captain declared an emergency and landed at Manchester Airport.

Aeronca 50 Chief: The Aeronca Model 50 Chief was an American light plane of the late 1930s.  Consumer demand for more comfort, longer range and better instrumentation resulted in its development in 1938, powered by a 50-horsepower (37-kilowatt) Continental, Franklin or Lycoming engine.  A 65-horsepower (48-kilowatt) Continental engine powered the Model 65 Super Chief, which was also built in a flight trainer version, the Model TC-65 Defender, with its rear seat positioned nine inches (23 centimeters) higher than the front for better visibility.

LeRoy W. Homer Jr. Foundation: The LeRoy W. Homer Jr.  Foundation is a national 501(c)(3) non-profit organization founded in memory of First Officer LeRoy W. Homer Jr..  LeRoy Homer was the co-pilot of United Airlines Flight #93, which crashed in Shanksville, Pennsylvania on September 11, 2001.  The flight recordings revealed that Dahl and Homer survived the initial attack and were still alive after the hijackers took over the plane.  It is believed that Dahl and Homer took actions to interfere with the hijackers, including disengaging the autopilot just before the hijackers took over in order to prevent them from setting the plane's target coordinates for Washington, D.C., and switching the output of the pilots' microphones from the cabin address speakers to the radio transmitter so that Jarrah's attempts to communicate with the passengers would instead be heard by air traffic controllers.  After learning of the earlier crashes at the thumb|right|World Trade CenterMelodie and the Pentagon, the crew and passengers attempted to foil the hijacking and reclaim the aircraft.  Meanwhile, the hijackers were not able to disengage the autopilot.  Dahl continued to struggle in the cockpit, refusing to allow a hijacker to deactivate the autopilot so he could fly the plane manually.  The hijackers were heard to say "Inform them, and tell him to talk to the pilot; bring back the pilot", possibly referring toLaurel Homer (CVR transcripts).  However, the uprising of crew and passengers took place and during the attempt the plane crashed into a field in Stonycreek Township, Pennsylvania2002.  The crash killed everyone on board.  Before the plane went down, she says, he had regained consciousness and was part of the final attack that forced the plane to abort its intended target, which was somewhere in Washington, D.C., and crash.ref>]]

Fiat 615: At first the model had a new petrol engine with 1395 cc and 29 kW (39 hp) at 3800 rpm to 1400 Fiat, and had a manual 4-speed transmission.  A 1.5 ton truck was newly developed, which was offered from 1951 in a flatbed and chassis for special bodies.  It was powered by the engine of the prior year featured Fiat 1400s.  The engine was already in the car Fiat 1400 was just sufficient, and with the 3.1 tons it had real trouble.  Once in motion, the Fiat 615 was indeed 80 km/hr fast, but with forced driving it had poor fuel efficiency.  There was a reason that the 1100 Fiat ELR far built until 1954.  The somewhat weaker beast of burden was, with its 1.1 liter and 28/30 PS (at 4400 rpm) a little lame, but it had fully loaded a ton to move less weight, so was more economical.  It therefore retained its loyal following who forgave its manageable liveliness out of habit, especially as it came with start-up to a peak of over 90 km/hr and thus was significantly faster than the Fiat 615 with its maximum of 78 km/hr.  With high pressure, therefore a suitable diesel engine was developed by Fiat: a swirl chamber engine (Ricardo System) based on the 1.9 liter engine for the "big" Fiat in 1900 and the new SUV Fiat Campagnola.  (This engine was a hubvergrößerte variant of the 1400 engine.)  The new diesel engine (type 305) was later also available in either sedan 1400 from 1952 in addition to the Fiat 615 N (N = Nafta = Diesel) and one year in Fiat Campagnola and Fiat.  Although the experiment of the Fiat 615 built 1.9 L gasoline engine proved to be stronger and with faster drive spurt, confined themselves to the diesel, the Type 615 N. Only Steyr in Austria until 1958 offered the Fiat 615 as gasoline, as Steyr 260 with its own 50 hp 2 L gasoline engine from the car Steyr 2000.  The Fiat 615 N was a very modern vehicle that in Italy, initially had no competition.  The export ran well at the beginning, missing, or half-hearted development left the Fiat 615 N (and especially its successor) over the years become increasingly rare even in Italy.  In Zastava in Yugoslavia, the Fiat 615 was built with a petrol engine under license.  However, not as the beginning of the Fiat, with the 1.4 L 4-cylinder engine, but with the much stronger torque 1.9 liter engine (type 105) with 47 hp at 3500 RPM, as well as in the, also at Zastava built under license, Campagnola was used.  It is unclear whether the successor (from about 1963, as Fiat 615 N1) only with the 1.9 liter petrol engine (such as 615 B) was built, with a diesel engine.

Tiltrotor: A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called "proprotors") mounted on rotating engine pods or nacelles usually at the ends of a fixed wing or an engine mounted in the fuselage with drive shafts transferring power to rotor assemblies mounted on the wingtips.  It combines the vertical lift capability of a helicopter with the speed and range of a conventional fixed-wing aircraft.  For vertical flight, the rotors are angled so the plane of rotation is horizontal, lifting the way a helicopter rotor does.  As the aircraft gains speed, the rotors are progressively tilted forward, with the plane of rotation eventually becoming vertical.  In this mode the wing provides the lift, and the rotor provides thrust as a propeller.  Since the rotors can be configured to be more efficient for propulsion (e.g. with root-tip twist) and it avoids a helicopter's issues of retreating blade stall, the tiltrotor can achieve higher speeds than helicopters.

T42 medium tank: The 90mm GUN TANK T42 was a medium tank powered by the AOS-895-3, a 6-cylinder, Air cooled, Opposed cylinder, Supercharged engine displacing 895.9 cubic inches.  It was intended to fulfill OTCM 32529's, dated December 2, 1948, call for a tank weighing 36 tons and equivalently armed as the M46 while having superior armour.  With an engine producing only 500 hp, concern about the T42's performance was expressed.  Testing, with a T40 loaded to the weight of T42 and powered by the AOS-895 through a CD-500 transmission, revealed it to be only equivalent in performance to the late model M4A3, which was below the design estimates.

Aviatik D.III: The Aviatik D.III was a German prototype single-seater fighter plane from the First World War, designed by Aviatik.  It became the basis for the Aviatik D.IV and Aviatik D.V.  In November 1917, the plane was first flown, using a 195 hp Benz Bz IIIbo gearless engine.  It was of similar design to the Aviatik D.II, and was armed with two LMG 08/15 machine guns.  After several tests at Adlershof from February 9–12, 1918, the plane underwent modifications, as requested by the Idflieg.  In April, a second prototype, powered by a Benz Bz IIIbm, although several D.III powered by the original IIIbo engine were already under production; however, none of them were ever completed.

Chengdu J-20: The Chengdu J-20 () is a stealth, twinjet, fifth-generation fighter aircraft developed by China's Chengdu Aerospace Corporation for the People's Liberation Army Air Force (PLAAF).  The J-20 made its maiden flight on 11 January 2011, but the plane was officially revealed on China International Aviation & Aerospace Exhibition in 2016.  In March 2017, Chinese media claimed that the aircraft has entered initial operational capability phase with limited service within Air Force.

Supporting paragraphs: Xian WS-15 Chengdu J-20
Answer: China International Aviation & Aerospace Exhibition