Boeing 727-22 "Jet Mainliner"
Boeing 727-22 "Jet Mainliner" (N7017U) at the Museum of Science and Industry, Chicago, IL (Photo by John Shupek)
The Boeing 727 is a mid-size narrow-body three-engine jet aircraft built by Boeing Commercial Airplanes from the early 1960s to 1984. It can carry 149 to 189 passengers and later models can fly up to 2,700 nautical miles (5,000 km) nonstop. Intended for short and medium-length flights, the 727 can use fairly short runways at smaller airports. It has three Pratt & Whitney JT8D engines below the 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. The 727 is Boeing's only tri-jet aircraft.
The 727 followed the 707, a quad-jet airliner, with which it shares its upper fuselage cross-section and cockpit design. The 727-100 first flew in February 1963 and entered service with Eastern Air Lines in February 1964; the stretched 727-200 flew in July 1967 and entered service with Northeast Airlines that December. The 727 became a mainstay of airlines' domestic route networks and was also used on short-range and medium-range international routes. Passenger, freighter, and convertible versions of the 727 were built.
The 727 was heavily produced into the 1970s; the last 727 was completed in 1984. As of July 2013, a total of 109 Boeing 727s (5 × 727-100s and 104 × 727-200s) were in commercial service with 34 airlines. Airport noise regulations have led to 727s being equipped with hush kits.
The Boeing 727 design was a compromise among United Airlines, American Airlines, and Eastern Air Lines requirements for a jet airliner to serve smaller cities with shorter runways and fewer passengers. United Airlines wanted a four-engine aircraft for its flights to high-altitude airports, especially its hub at Stapleton International Airport at Denver, Colorado. American, which was operating the four-engine Boeing 707 and Boeing 720, wanted a twin-engine aircraft for efficiency. Eastern 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/LROPS). Eventually the airlines agreed on a trijet.
Production of the 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. The two designs had a similar layout, the 727 being slightly larger. 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. Boeing and de Havilland each sent engineers to the other company's locations to evaluate each other's designs, but Boeing eventually decided against the joint venture. De Havilland had wanted Boeing to license-build the D.H.121, while Boeing felt that the aircraft needed to be designed for the American market, with six-abreast seating and the ability to use runways as short as 4,500 ft.
In 1960 Pratt & Whitney was looking for a customer for its new JT8D turbofan design study, based on its J52 (JT8A) turbojet, while United and Eastern were interested in a Pratt & Whitney alternative to the RB163 Spey. 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. Boeing had not offered the JT8D as it was about 1,000 lbs heavier than the RB163, though slightly more powerful; the RB163 was also further along in development than the JT8D. Boeing reluctantly agreed to offer the JT8D as an option on the 727 and it later became the sole powerplant.
With high-lift devices on its wing the 727 could use shorter runways than most earlier jets (e.g. the 4800-ft runway at Key West).
Later 727 models were stretched to carry more passengers and replaced earlier jet airliners such as the Boeing 707 and Douglas DC-8 as well as aging prop airliners such as the DC-4, DC-6, DC-7 and the Lockheed Constellations on short-haul and medium-haul routes.
For over a decade more 727s were built per year than any other jet airliner; in 1984 production ended with 1,832 built with 1,831 delivered, the highest total for any jet airliner until the 737 surpassed it in the early 1990s.
The airliner's middle engine (engine 2) at the very rear of the fuselage gets air from an inlet ahead of the vertical fin through an S-shaped duct. 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. This was fixed by the addition of several large vortex generators in the inside of the first bend of the duct.
The 727 was designed for smaller airports, so independence from ground facilities was an important requirement. 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. Hijacker D. B. Cooper parachuted from the back of a 727 as it was flying over the Pacific Northwest. Boeing subsequently modified the design with the Cooper vane so that the airstair could not be lowered in flight. 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. 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 727 is equipped with a retractable tail skid that is designed to protect the aircraft in the event of an over-rotation on takeoff. The 727's fuselage has an outer diameter of 148 inches (3.8 m). This allows six-abreast seating (three per side) and a single aisle when 18-inch (46 cm) wide coach-class seats are installed. An unusual feature of the fuselage is the 10-inch (25 cm) difference between the lower lobe forward and aft of the wing as the higher fuselage height of the center section was simply retained towards the rear.
Nose wheel brakes were available as an option to reduce braking distance on landing, which provided reductions in braking distances of up to 150 m.
The 727 proved to be such a reliable and versatile airliner that it came to form the core of many startup airlines' fleets. The 727 was successful with airlines worldwide partly because it could use smaller runways while still flying medium-range routes. This allowed airlines to carry passengers from cities with large populations but smaller airports to worldwide tourist destinations. One of the features that gave the 727 its ability to land on shorter runways was its clean wing design. 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, aft-moving flaps) could be used on the entire wing. Together these high-lift devices produced a maximum wing lift coefficient of 3.0 (based on the flap-retracted wing area). 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-degree flaps setting could result in a higher-than-desired sink rate or a stall on final approach. These carriers' Pilots' Operation Handbooks disallowed using more than 30 degrees of flaps on the 727, even going so far as installing plates on the flap lever slot to prevent selection of more than 30 degrees of flaps.
The 727 is one of the noisiest commercial jetliners, categorized as Stage 2 by the U.S. Noise Control Act of 1972, which mandated the gradual introduction of quieter Stage 3 aircraft. The 727's JT8D jet engines use older low-bypass turbofan technology, whereas Stage 3 aircraft utilize the more efficient and quieter high-bypass turbofan design. When the Stage 3 requirement was being proposed, Boeing engineers analyzed the possibility of incorporating quieter engines on the 727. They determined that the JT8D-200 engine could be used on the two side-mounted pylons, but the structural changes to fit the larger-diameter engine (49.2 inches (125 cm) fan diameter in the JT8D-200 compared to 39.9 inches (101 cm) in the JT8D-7) into the fuselage at the number two engine location were prohibitive.
Current regulations require that a 727 in commercial service must be retrofitted with a hush kit to reduce engine noise to Stage 3 levels. One such hush kit is offered by FedEx, and has been purchased by over 60 customers. Aftermarket winglet kits, originally developed by Valsan Partners and later marketed by Quiet Wing Corp. have been installed on many 727s to reduce noise at lower speeds, as well as to reduce fuel consumption. Kelowna Flightcraft's maintenance division in Canada has installed winglets on Donald Trump's private 727-100. In addition, Raisbeck Engineering developed packages to enable 727s to meet the Stage 3 noise requirements. These packages managed to get light-weight and medium-weight 727s to meet Stage 3 with simple changes to the flap and slat schedules. For heavier-weight 727s, exhaust mixers must be added to meet Stage 3. American Airlines ordered and took delivery of 52 Raisbeck 727 Stage 3 systems. Other customers included TWA, Pan Am, Air Algérie, TAME and many smaller airlines.
From September 1, 2010, 727 jetliners (including those with a hush kit) are banned from some Australian airports due to noise.
In addition to domestic flights of medium range, the 727 was popular with international passenger airlines. The range of flights it could cover (and the additional safety added by the third engine) meant that the 727 proved efficient for short-range to medium-range international flights in areas around the world. Prior to its introduction, four-engine jets or propeller-driven airliners were required for transoceanic service.
The 727 also proved popular with cargo airlines and charter airlines. FedEx Express introduced 727s in 1978. 727s were the backbone of its fleet until the 2000s; FedEx began replacing them with Boeing 757s in 2007. Many cargo airlines worldwide employ the 727 as a workhorse, since, as it is being phased out of U.S. domestic service due to noise regulations, it becomes available to overseas users in areas where such noise regulations have not yet been instituted. Charter airlines Sun Country, Champion Air, and Ryan International Airlines all started with 727 aircraft.
The 727 saw some military use as well. 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.
The 727 has proven to be popular where the airline serves airports with gravel, or otherwise lightly improved runways. The Canadian airline First Air, for example, previously used a 727-100C to service the communities of Resolute Bay and Arctic Bay in Nunavut, whose Resolute Bay Airport and former Nanisivik Airport both have gravel runways. The high mounted engines greatly reduce the risk of foreign object damage.
According to the Boeing Jetliner Databook, the Justice Prisoner and Alien Transportation System, also known as 'Con Air', currently uses four 727 aircraft to transport persons in legal custody between prisons, detaining centers, courthouses, and other places to where they must be transported.
A military version, the Boeing C-22 was operated as a medium-range transport aircraft by the Air National Guard and National Guard Bureau to airlift personnel. A total of three C-22Bs were in use, all assigned to the 201st Airlift Squadron, District of Columbia Air National Guard.
At the start of the 21st century, the 727 remained in service with a few large airlines. 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-engine aircraft, which are quieter, and more fuel-efficient. Modern airliners also have a smaller flight deck crew of two pilots, while the 727 required two pilots and a flight engineer. Delta Air Lines, the last major U.S. carrier to do so, retired its last 727 from scheduled service in April 2003. Northwest Airlines retired its last 727 from charter service in June 2003. The 727 is still flying for some smaller start-up airlines, cargo airlines, and charter airlines. Many airlines replaced their 727s with either the 737-800 or the Airbus A320; both are closer in size to the 727-200. As of July 2013, a total of 109 Boeing 727s (5 × 727-100s and 104 × 727-200s) were in commercial service with 34 airlines.
On March 2, 2016, the first 727 produced (N7001U), which first flew on February 9, 1963, made its final flight. The 727-100 had carried about 3 million passengers during its years of service. Originally a prototype, it was later sold to United Airlines, which donated it to the museum in 1991. The Federal Aviation Administration granted the museum a special permit for the 15 minute flight. The jet was restored over 25 years by the Museum of Flight in Seattle and was ferried from Paine Field in Everett, Washington to Boeing Field in Seattle, where it was put on permanent display at the Aviation Pavilion. The museum's previous 727-223, tail number N874AA, was donated to the National Airline History Museum in Kansas City and will be flown to its new home once FAA ferry approval is granted.
There are two series of 727; the initial 100 (originally only two figures as in 727-30) was launched in 1960 and entered service in February 1964. The 727-200 series was launched in 1965 and entered service in December 1967.
The first 727-100 (N7001U) flew on February 9, 1963 and 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, Florida, Washington, D.C., and Philadelphia, Pennsylvania.
A total of 571 Boeing 727-00/100 series aircraft were delivered (407 727-100s, 53 727-100Cs, and 111 727-100QCs), the last in October 1972. One 727-100 was retained by Boeing, bringing total production to 572.
The 727-100 designation is a retroactive one to distinguish the original short-body version. Aircraft for United Airlines were delivered as 727-22, for American Airlines as 727-23 and so on - not 727-122 and 727-123 - and retained these designations even after the advent of the 727-200.
Convertible passenger cargo version. Additional freight door and strengthened floor and floor beams. Three alternate fits:
QC stands for Quick Change. This is similar to the Convertible version with a roller-bearing floor for palletised galley and seating and/or cargo to allow much faster changeover time (30 minutes).
Stretched version of the 727-100. The 727-200 is 20 feet (6.1 m) longer (153 feet 2 inches; 46.69 m) than the 727-100 (133 feet 2 inches; 40.59 m). A ten-foot (3-meter) fuselage section ("plug") was added in front of the wings and another ten-foot fuselage section was added behind them. The wing span and height remain the same on both the 727-100 and 727-200 (108 and 34 feet (33 and 10 m), respectively). The original 727-200 had the same max gross weight as the 727-100; however, as the aircraft evolved, a series of higher gross weights and more powerful engines was introduced along with other improvements, and, from line number 881, 727-200s are dubbed 727-200 Advanced. The aircraft gross weight eventually increased from 169,000 to 209,500 pounds (76,700 to 95,000 kg) for the latest versions. The dorsal intake of the number two engine was also redesigned to be round in shape, rather than oval as it was on the 100 series.
The first 727-200 flew on July 27, 1967 and received FAA certification on November 30, 1967. The first delivery was made on December 14, 1967 to Northeast Airlines. A total of 310 727-200s were delivered before its place on the production line was taken over by the 727-200Advanced in 1972.
Convertible passenger cargo version. One was built.
The Advanced version of the 727-200, introduced in 1970, gave the program a new source of life. More powerful engines, increases in both fuel capacity and MTOW, and an increase in range by nearly 50%, combined with excellent economics and improved interior, made the 727-200Advanced a major success. After the first delivery in mid 1972, Boeing eventually raised production to more than a hundred a year to meet demand by the late seventies. Of the passenger model of the 727-200Advanced, a total of 935 were delivered after which it had to give way to a new generation of aircraft.
Boeing 727-200F Advanced
A freighter version of the 727-200 Advanced became available in 1981 designated the Series 200F Advanced powered by the Pratt & Whitney JT8D-17A engines and featured a strengthened fuselage structure, an 11 ft 2 inch by 7 ft 2 inch forward main deck freight door and a windowless cabin. This was the last production variant of the 727 to be developed by Boeing, and 15 aircraft were built, all for Federal Express; the last 727 aircraft completed by Boeing was a 727-200F Advanced.
Speed increased by 50 mph (80 km/h), due to replacement of the two side engines with the JT8D-217 or the JT8D-219, which are also found on many MD-80s, along with the addition of hush kits to the center engine. Winglets were added to some of these aircraft to increase fuel efficiency. This modification was originally developed by Valsan Partners, but was later marketed by Quiet Wing Technologies in Redmond, Washington.
Single 727-212 aircraft operated by the USAF
As of June 2013, 188 Boeing 727 aircraft (all variants) are in commercial airline, private, and government service. Most airlines have small numbers but the following operate five or more aircraft:
Government, Military, and Other Operators
In addition, the 727 has seen sporadic government use, having flown for the Belgian, Yugoslavian, Mexican, New Zealand, and Panama air forces, among the small group of government agencies that have used it.
Boeing 727-100 Series Specifications
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