After the heavier 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airports.
The only trijet aircraft to be produced by Boeing, the 727 is powered by three Pratt & Whitney JT8D low-bypass turbofans below a T-tail, one on each side of the rear fuselage and a center one fed through an S-duct below the tail.
Launched in 1965, the stretched 727-200 flew in July 1967 and entered service with Northeast Airlines that December.
[6] 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.
At that time Boeing intended to use three Allison AR963 turbofan engines, license-built versions of the Rolls-Royce RB163 Spey used by the Trident.
[13] Once Pratt & Whitney agreed to go ahead with development of the JT8D, Eddie Rickenbacker, chairman of the board of Eastern, told Boeing that the airline preferred the JT8D for its 727s.
[18] This S-duct proved to be troublesome in that flow distortion in the duct induced a surge in the centerline engine on the take-off of the first flight of the 727-100.
Boeing subsequently modified the design with the Cooper vane so that the airstair could not be lowered in flight.
An unusual design feature is that the APU is mounted in a hole in the keel beam web, in the main landing gear bay.
This allowed airlines to carry passengers from cities with large populations, but smaller airports to worldwide tourist destinations.
[15] With no wing-mounted engines, leading-edge devices (Krueger, or hinged, flaps on the inner wing and extendable leading edge slats out to the wingtip) and trailing-edge lift enhancement equipment (triple-slotted,[22] Fowler flaps) could be used on the entire wing.
[19] The 727 was stable at very low speeds compared to other early jets, but some domestic carriers learned after review of various accidents that the 40° flap setting could result in a higher-than-desired sink rate or a stall on final approach.
[26] In addition, Raisbeck Engineering developed packages to enable 727s to meet the Stage 3 noise requirements.
These packages managed to get light- and medium-weight 727s to meet Stage 3 with simple changes to the flap and slat schedules.
Since the aft stair could be opened in flight, the Central Intelligence Agency used them to drop agents and supplies behind enemy lines in Vietnam.
Known as 'Faw-727', it was reportedly used as an ELINT platform in the invasion of Kuwait in 1990 (during which it was briefly locked on by a Kuwaiti Mirage F1 on August 2) and the subsequent Iraqi monitoring of Coalition forces during Desert Shield.
[32][33] The 727 has proven to be popular where the airline serves airports with gravel, or otherwise lightly improved, runways.
Faced with higher fuel costs, lower passenger volumes due to the post-9/11 economic climate, increasing restrictions on airport noise, and the extra expenses of maintaining older planes and paying flight engineers' salaries, most major airlines phased out their 727s; they were replaced by twin-engined aircraft, which are quieter and more fuel-efficient.
[40] After a series of financial problems with the restoration, N874AA was seized by Boeing Field for nonpayment of storage fees in 2021 and subsequently broken up and scrapped.
[37] FAA type approval was awarded on December 24 of that year, with initial delivery to United Airlines on October 29, 1963, to allow pilot training to commence.
The first 727 passenger service was flown by Eastern Air Lines on February 1, 1964, between Miami, Washington, DC, and Philadelphia.
This is similar to the convertible version with a roller-bearing floor for palletised galley and seating and cargo to allow a much faster changeover time of 30 minutes.
A cargo conversion for United Parcel Service, these were re-engined with Stage 3-compliant Rolls-Royce Tay turbofans.
The aircraft gross weight eventually increased from 169,000 to 209,500 pounds (76,700 to 95,000 kg) for the latest versions.
[45] It featured powerful engines, fuel capacity and MTOW (185,800–210,000 lb or 84.3–95.3 t) increased the range from 1,930 to 2,550 nmi (3,570 to 4,720 km; 2,220 to 2,930 mi) or by 32%.
[46] After the first delivery in mid-1972, Boeing eventually raised production to more than a hundred per year to meet demand by the late 1970s.
Certificated by Valsan Partners in December 1988 and marketed by Goodrich from 1997, the side engines are replaced by more efficient, quieter JT8D-217C/219, and the center engine gains a hush kit for $8.6 million (but loses the thrust reverser) (2000): fuel consumption is reduced by 10-12%, range and restricted airfield performance are improved.
A proposed 169-seat version was developed in consultation with United Airlines in 1972, which initially expressed an interest in ordering 50 aircraft.
More compact systems, a redesign of the internal space, and removing the need for the flight engineer would have increased the capacity to 189 seats in a two-class configuration.
A number of 727s have been outfitted for use as private aircraft, especially since the early 1990s, when major airlines began to eliminate older 727-100 models from their fleet.