Skyships Eng 86,923 views. de Havilland certainly met with Boeing wand they both had access to each others plans. The earlier posts are correct and accurate in that this airplane was designed to meet BEA's needs, and, as a result, was simply too small. Intended for short and medium-length flights, the 727 can use relatively short runways at smaller airports. Trident Hawker Siddeley Trident 2E Hawker Siddeley Trident 1C In 1959, Lord Douglas, chairman of British European Airways (BEA), suggested that Boeing and de Havilland Aircraft Company (later Hawker Siddeley) work together on their trijet designs, the 727 and D.H.121 Trident, respectively. Earl Sutton Hawker Siddeley HS 121 Trident (UK; orig. As far as I know it was the first airliner to be landed automatically on a scheduled flight: B. Cooper is an unidentified man who hijacked a Boeing 727 aircraft in the northwest United States, in the airspace between Portland, Oregon, and Seattle, Washington, on the afternoon of Wednesday, November 24, 1971.An unusual design feature is that the APU is mounted in a hole in the keel beam web, in the main landing gear bay.The Boeing 727 is an American midsized, narrow-body three-engined jet aircraft built by Boeing Commercial Airplanes from the early 1960s to 1984.In 1959, Lord Douglas, chairman of British European Airways (BEA), suggested that Boeing and de Havilland Aircraft Company (later Hawker Siddeley) work together on their trijet designs, the 727 and D.H.121 Trident, respectively.Other airlines found it unattractive and turned to a rival tri-jet, the Boeing 727 which was much the same size as the initial DH 121 design.Eastern Airlines wanted a third engine for its overwater flights to the Caribbean, since at that time twin-engine commercial flights were limited by regulations to routes with 60-minute maximum flying time to an airport (see ETOPS).The JT8D was reliably powering the three-engined Boeing 727.In 1959, Lord Douglas, chairman of British European Airways (BEA), suggested that Boeing and de Havilland Aircraft Company (later Hawker Siddeley) work together on their trijet designs, the 727 and D.H.121 Trident, respectively.In the mid-1960s, BEA's European rivals began placing orders for new "second-generation" jet aircraft, such as the Boeing 727-200 and its smaller stablemate, the 737-200, as well as the Douglas DC-9-30/40.It has three Pratt & Whitney JT8D engines below a T-tail, one on each side of the rear fuselage with a center engine that connects through an S-duct to an inlet at the base of the fin.A 1977 legislative change (Public Law 95-163) removed restrictions on the routes operated by all-cargo airlines, and enabled Federal Express to purchase its first large aircraft: seven Boeing 727-100s.Airport noise regulations have led to 727s being equipped with hush kits.On a larger aircraft, like Federal Express's Boeing 727s, the hush kits add 900 lb of extra weight (total airplane weight up to 190000 lb) and this results in an overall 0.5% increase in fuel burn for short trips (but no measurable increase for long flights).This led to one of the 727's most distinctive features: the built-in airstair that opens from the rear underbelly of the fuselage, which initially could be opened in flight.Some aircraft, like the Boeing 727 and McDonnell Douglas DC-9, were designed to improve ground services, with passengers deplaning from the front as the aircraft is serviced from the rear, enabling quicker turnarounds.Charter airlines Sun Country, Champion Air, and Ryan International Airlines all started with 727 aircraft.Based at the Chicago Rockford International Airport in Rockford, Illinois, the US Postal Service was once the airline's main customer, utilizing Boeing 727 aircraft operated by Ryan International on scheduled mail delivery flights.The Canadian airline First Air, for example, previously used a 727-100C to serve the communities of Resolute Bay and Arctic Bay in Nunavut, whose Resolute Bay Airport and former Nanisivik Airport both have gravel runways.Northwest Territorial operated Boeing 727-100 and Boeing 737-200 jetliners, Lockheed L-188 Electra propjets, Lockheed L-100 Hercules cargo turboprops and Douglas DC-3s.Charter airlines Sun Country, Champion Air, and Ryan International Airlines all started with 727 aircraft.Sun Country began flight operations in January 1983 with a single Boeing 727-200 jetliner.Another innovation was the auxiliary power unit (APU), which allowed electrical and air-conditioning systems to run independently of a ground-based power supply, and without having to start one of the main engines.The Boeing 727 in 1963 was the first jetliner to feature a gas turbine APU, allowing it to operate at smaller airports, independent from ground facilities.The 727 is equipped with a retractable tailskid that is designed to protect the aircraft in the event of an over-rotation on takeoff.Certain airplanes like the Boeing 727, Boeing 767, and Concorde require a high degree of rotation during takeoff, but not all airplanes require this degree of rotation.allowing twin engine aircraft to operate on long overwater routes The Boeing 727 is an American midsized, narrow-body three-engined jet aircraft built by Boeing Commercial Airplanes from the early 1960s to 1984. The Hawker Siddeley HS-121 Trident (originally the de Havilland DH.121 and briefly the Airco DH.121) is a now-retired British short- (and later medium-) range airliner. Max Take Off Weight: 95,029 Kg 209,501 lbs Max Landing Weight: Max Payload: 28,623 Kg 63,102 lbs Fuel Tank Capacity: 9,806 gallon 37,120 litre Baggage Volume: So, it really is not all that surprising that airframe manufacturers come up with similar looking aircraft when presented with the same requirement and using similar engines.