Classic Jetliners: The Boeing 727

I have a vivid memory from my childhood in the 1980s of watching planes fly over my house. The Boeing 727 was one of the most unforgettable planes to grace the skies, along with other iconic aircraft like the PAL BAC 1-11 and the Hawker Siddeley HS748. The sound of the PAL Boeing 727 as it soared overhead was truly unforgettable. Now, it’s time to take a closer look at this beloved aircraft and explore what makes it stand out from the rest.

If you were to ask aviation enthusiasts to name some of the most iconic aircraft of all time, the Boeing 727 would definitely be one of the top picks. This narrow-body airliner has been around since the early 1960s, and its unique features have made it a favorite among pilots and passengers alike. From its sleek design to its impressive range and capacity, the Boeing 727 has played a significant role in shaping the modern aviation industry.

What is a Boeing 727?

Let’s take a trip back in time to the swinging 60s when air travel was taking off (quite literally!) and airlines were clamoring for shorter flight lengths from smaller airports. Enter the Boeing 727 – an American narrow-body airliner that quickly captured the hearts of aviation enthusiasts and everyday travelers alike.

With 40 orders each from United Airlines and Eastern Air Lines, the 727 was officially launched on December 5, 1960. The first 727-100 rolled out on November 27, 1962, and entered service with Eastern on February 1, 1964. This trijet aircraft was unique in that it was powered by Pratt & Whitney JT8D low-bypass turbofans below a T-tail, and it shared its six-abreast upper fuselage cross-section and cockpit with the 707.

The 727-100 was 133 feet (40.5 meters) long and typically carried 106 passengers in two classes over 2,250 nautical miles (4,170 kilometers), or 129 in a single class. The longer 727-200 was introduced in 1965 and flew in July 1967, entering service with Northeast Airlines that December. It was 20 feet (6.1 meters) longer than its predecessor and typically carried 134 passengers in two classes over 2,550 nautical miles (4,720 kilometers), or 155 in a single class. Not only was it used for domestic and international flights, but also as a freighter and Quick Change convertible version. However, with airport noise regulations in place, hush kit installations became necessary for the 727’s continued use.

Although its last commercial passenger flight was in January 2019, the 727 has left a lasting impact on the aviation industry. It was succeeded by the 757-200 and larger variants of the 737. As of February 2022, there were 38 Boeing 727s still in commercial service, and 1,832 had been built before production ended in September 1984. The 727 may no longer grace the skies, but it will forever be remembered as a trailblazer in aviation history.

A Unique Design

One of the most distinctive features of the Boeing 727 was the middle engine (engine 2) located at the very rear of the fuselage, which was fed air from an inlet ahead of the vertical fin through an S-shaped duct. However, this S-duct was problematic as it caused flow distortion in the duct that induced a surge in the centerline engine during the take-off of the first flight of the 727-100. This issue was fixed by adding several large vortex generators inside the first bend of the duct.

Designed for smaller airports, the 727 had to be independent from ground facilities. This requirement led to the aircraft’s most distinctive feature: the built-in airstair that opens from the rear underbelly of the fuselage, which initially could be opened in flight. Hijacker D. B. Cooper famously used this hatch when he parachuted from the back of a 727 over the Pacific Northwest. The design was subsequently modified with the Cooper vane to prevent the airstair from being lowered in flight. Another unique design feature was the auxiliary power unit (APU), which allowed electrical and air-conditioning systems to run independently of a ground-based power supply without having to start one of the main engines.

Despite these unique features, the 727 was highly successful and versatile, forming the core of many startup airlines’ fleets. The 727’s clean wing design made it capable of landing on shorter runways while still flying medium-range routes, making it ideal for carrying passengers from cities with large populations but smaller airports to worldwide tourist destinations. The 727’s wing design also allowed the use of high-lift 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, fowler flaps) on the entire wing, producing a maximum wing lift coefficient of 3.0. However, some domestic carriers learned that the 40-degree flap setting could result in a higher-than-desired sink rate or a stall on final approach, and as a result, they disallowed using more than 30° of flaps on the 727.

A Very Loud Aircraft

As I’ve previously mentioned, the Boeing 727 was notorious for its deafening noise, especially during takeoff. The rumble it produced was so intense that it could shake the furniture in our house. In fact, a 727 passing above our home in the early hours of the morning was akin to an alarm clock!

Well, the 727 is categorized as Stage 2 by the U.S. Noise Control Act of 1972, which mandated the gradual introduction of quieter Stage 3 aircraft. This means that the JT8D jet engines used by the 727 are using older low-bypass turbofan technology compared to newer and quieter high-bypass turbofan designs of Stage 3 aircraft.

While the JT8D-200 engines, which are quieter and more fuel efficient, could be used to replace the original engines, fitting them into the fuselage was a structural nightmare. Hence, regulations now require retrofitting of a hush kit to a 727 to reduce engine noise to Stage 3 levels to continue flying in U.S airspace. FedEx offers one of the hush kits that have been purchased by over 60 customers. Meanwhile, aftermarket winglet kits have been installed on many 727s to reduce noise at lower speeds and fuel consumption. Raisbeck Engineering also developed packages to enable 727s to meet the Stage 3 noise requirements, allowing many airlines to continue using the plane. However, since September 1, 2010, 727 jetliners are banned from some Australian airports due to their noise levels.

Variants and Specs

727-100

The 727-100 was the initial variant of the aircraft, and it was launched in 1960. The first 727-100 flew on February 9, 1963, and FAA type approval was awarded on December 24 of that year. The initial delivery to United Airlines took place 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.

Here are some specifications of the 727-100:

• Flight crew: three (pilot, copilot, and flight engineer)
• Two-class seats: 106
• One-class seats: 125
• Exit limit: 131
• Length: 133 ft 2 in / 40.59 m
• Height: 34 ft 3 in / 10.44 m
• Cabin width: 140 in / 3.56 m
• Wingspan: 108 ft / 32.92 m
• Wing: 1,650 sq ft (153 m2), 32° sweep
• MTOW: 169,000 lb / 76,700 kg
• OEW: 87,696 lb / 39,800 kg
• Fuel capacity: 7,680 gal / 29,069 L
• Engines: three Pratt & Whitney JT8D-1/7/9
• Thrust: 14,000–14,500 lbf (62–64 kN)
• Range: 2,250 nmi (4,170 km)
• Take-off: 8,300 ft (2,500 m)
• MMO: Mach 0.9 (961 km/h; 519 kn)
• Cruise: 495–518 kn / 917–960 km/h
• Ceiling: 42,000 ft (13,000 m)

The 727-100 had several variants, including:

• 727-100C: Convertible passenger cargo version, with additional freight door and strengthened floor and floor beams.
• 727-100QC: Quick Change variant, similar to the convertible version but with a roller-bearing floor for palletized galley and seating and/or cargo to allow for faster changeover time.
• 727-100QF: Quiet Freighter variant, a cargo conversion for United Parcel Service that was re-engined with Stage 3-compliant Rolls-Royce Tay turbofans.

727-200

The 727-200 was a stretched version of the 727-100, with a 10-ft (3-m) fuselage section (“plug”) added in front of and behind the wings. 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.

Here are some specifications of the 727-200:

• Flight crew: three (pilot, copilot, and flight engineer)
• Two-class seats: 134
• One-class seats: 155
• Exit limit: 189
• Length: 153 ft 2 in / 46.68 m
• Height: 34 ft 11 in / 10.65 m
• Cabin width: 140 in / 3.56 m
• Wingspan: 108 ft / 32.92 m
• Wing: 1,650 sq ft (153 m2), 32° sweep
• MTOW: 172,000 lb / 78,100 kg
• OEW: 97,650 lb / 44,330 kg
• Fuel capacity: 8,090 US gal / 30,620 L
• Engines: three JT8D-7/9/11 (Adv.: -9/15/17/17R)
• Thrust: 14,000–15,000 lbf (62–67 kN) (Adv.: 14,500–17,400 lbf (64–77 kN))
• Range: 1,900 nmi (3,500 km) (Adv.: 2,550 nmi (4,720 km))
• Take-off: 8,400 ft (2,600 m) (Adv.: 10,100 ft (3,100 m))
• MMO: Mach 0.9 (961 km/h; 519 kn)
• Cruise: 467–515 kn / 865–953 km/h
• Ceiling: 42,000 ft (13,000 m)

The 727-200 had several variants, including:

• 727-200C: Convertible passenger cargo version, with only one built.
• 727-200 Advanced: This variant was introduced in 1970 and featured powerful engines, fuel capacity, and MTOW increased range, as well as other improvements.
• 727-200F Advanced: A freighter version of the 727-200 Advanced, with a strengthened fuselage structure and an 11 ft 2 in by 7 ft 2 in forward main deck freight door. Fifteen of these aircraft were built, all for Federal Express.

History of the Boeing 727

The Boeing 727 was a game-changer in the world of aviation. It was designed as a compromise among United Airlines, American Airlines, and Eastern Air Lines, all of whom had different requirements for a jet airliner. United Airlines wanted a four-engine aircraft for high-altitude airports, American Airlines preferred a twin-engine aircraft for efficiency, and Eastern Airlines needed a third engine for its overwater flights. Eventually, the three airlines agreed on a trijet design for the new aircraft.

In 1959, British European Airways suggested that Boeing and de Havilland Aircraft Company work together on their trijet designs, the 727 and D.H.121 Trident, respectively. Although the two designs had a similar layout, Boeing decided against the joint venture and instead intended to use three Allison AR963 turbofan engines. However, Pratt & Whitney was looking for a customer for its new JT8D turbofan design study, and once Pratt & Whitney agreed to go ahead with development of the JT8D, Eastern Airlines preferred it for its 727s. 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. Later models of the 727 were stretched to carry more passengers and replaced earlier jet airliners such as the Boeing 707 and Douglas DC-8, as well as aging propeller airliners such as the DC-4, DC-6, DC-7, and the Lockheed Constellations on short- 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 and 1,831 delivered, the highest total for any jet airliner until the 737 surpassed it in the early 1990s. The Boeing 727 was truly a revolutionary aircraft that paved the way for the future of air travel.