Boeing 737-400

Today Boeing is in the process of producing the next-generation of 737s, comprised of the 600, 700, and 800 series, the first of which are squeduled for delivery in October 1997. Changes include a larger wing, higher cruise speed, increased range, and new engines with improvements in noise, fuel burn and thrust. With over 3,300 orders the Boeing 737 has become the world's all time best-selling commercial jetliner. Over 2,700 have already been delivered to more than 250 customers in 95 countries. By 1996, 737s had carried more than 4.3 billion passengers and flown more than 26.6 billion miles. Through March 31, 1996, the current generation 737 was the most reliable jet airplane in commercial aviation, with a dispatch reliability of 99.4%. Over 700 737s are in the sky at all times.

737-400 History

Boeing announced it was developing a new higher capacity version of the fast selling 737-300 in June 1986. The new aeroplane, the 737-400, was developed as a 150 seat class 727 replacement. Although Boeing had initially developed the 180 to 200 seat 757 to replace the successful 727, there still existed a considerable market for a near direct size replacement for the popular trijet. By developing the 737-400 as a minimum change stretch of the 737-300, Boeing was also able to offer considerable commonality, and thus cost, benefits to operators already with the 737-300, and to a lesser extent, the 737-200 in their fleets. The major change of the 737-400 over the smaller 300 is a 3.05m (10ft 0in) fuselage stretch, consisting of a 1.83m (6ft 0in) stretch forward and a 1.22m (4ft 0in) plug rear of the wing. The stretch increases maximum passenger seating to 188. To cope with the increased weights, more powerful CFM56s are fitted. Other changes are minor, such as a tail bumper fitted to protect against over rotation at takeoff, something that could have become a problem due to the increased fuselage length. A higher gross weight longer range version is offered. It features increased fuel capacity, and strengthened undercarriage and structures, but is otherwise identical to the standard 737-400. 

The first flight of the 737-400 occurred on February 19 1988 and it entered airline service in October that year with Piedmont. Of the 737-300/-400/-500 family the 400 has proven the most successful member behind the 300, its larger capacity and transcontinental US range meaning it has found a very useful market for Boeing as a 727 replacement. However the 737-400 does face stiff competition from the similar size Airbus A320, which has higher levels of technology, longer range and is faster (but is also heavier).

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