3
TheBoeing 727 is a midsized,narrow-bodytri-enginejet aircraft built byBoeing
Commercial Airplanesfrom the early 1960s to 1984.It can carry 149 to 189 passengers
and later models can fly up to 2,700nautical milesnonstop. Intended forshortand
medium-length flights, the 727 can use relatively short runways at smaller airports. It
has threePratt & Whitney JT8Dengines below theT-tail, one on each side of the rear
fuselage with a center engine that connects through anS-ductto an inlet at the base of
the fin. The 727 is Boeing's only trijet aircraft.
The Boeing 727 design was a compromise amongUnited Airlines,American Airlines,
andEastern Air Lines; each of the three had developed requirements for a jet airliner to
serve smaller cities with shorter runways and fewer passengers.United Airlines
requested a four-engine aircraft for its flights to high-altitude airports, especially its hub
atStapleton International AirportinDenver, Colorado.American Airlines, which was
operating the four-enginedBoeing 707andBoeing 720, requested a twin-engined
aircraft for efficiency. 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. Eventually, the
three airlines agreed on atrijetdesign for the new aircraft.
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-inairstairthat opens from the rear underbelly of the fuselage, which initially could
be opened in flight.HijackerD. B. Cooperused this hatch when he parachuted from the
back of a 727, as it was flying over thePacific Northwest. Boeing subsequently modified
the design with theCooper vaneso that the airstair could not be lowered in
flight.Another innovation was theauxiliary 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 mainlanding gearbay.
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-9/11economic
climate, increasing restrictions on airport noise, and the extra expenses of maintaining
older planes and payingflight engineers' salaries, most major airlines phased out their
727s; they were replaced bytwin-engined 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.
PART 1
–
INTRODUCTION
727
-
100