A versatile twinjet - Part I

In the middle of the 1970's, after the oil crisis when the fuel price drastically increased, the airlines were studying with different aircraft manufacturers a new airplane to replace the fuel thirsty Boeing 707 then in service widely. Airbus had just unveiled it's first model, the A300 which was the first widebody aircraft twinjet to enter commercial service.
Boeing has responded, in 1978, by announcing to the public two new fuel efficient models: the 757 and the 767. The 757 was to be a narrowbody aircraft designed to replace the 727 and the 767 was to be a widebody aircraft designed to replace the 707 and compete against the Airbus A300 and A310, both new models would be twinjets and share the same cockpit layout, which means that a flight crew licensed to fly on one aircraft can fly either model without much additional training. The FAA allowed then the 757/767 to be considered as one type rating, this is a reason why many airlines operate both models, to save pilot training and maintenance costs. The 757 and 767 are still built with aluminum but the new features compared to their predecessors are a two-pilot flight deck equipped with EFIS (Electronic Flight Instrumentation System) displays replacing dials, and lighter composite materials on the aircraft structure, thus reducing fuel consumption.
An other distinctive feature of the 767 is the landing gear configuration. The landing gears are fixed closer to the trailing edge of the wing so that the center of gravity of the aircraft is moved slightly backwards, which increases slightly fuel efficiency. A large aircraft is more stable if its center of gravity remains near the forward section of the aircraft but is more fuel efficient if its center of gravity is moved towards the rear of the aircraft. This explains why the wheels are tilted downwards when the landings gears are out on final approach to landing, as you can see in this picture.

Most airlines around the world have a 2-3-2 seating abreast in the Economy Class cabin of their 767 aircraft, except a few charter airlines which choose a 2-4-2 seating abreast configuration, but the 2-3-2 configuration is mostly preferred because no passenger is more than one seat away from an aisle.
The initial variant, the 767-200, first flew in 1981 out of Everett WA and entered service one year later with United. United introduced the 767 on long domestic routes in their system. Other major US airlines including TWA, American, and Delta quickly followed. Piedmont, merged into US Air in the late 1980's, also ordered the 767-200 in ER (Extended Range) version. Boeing introduced the 767-200ER in the middle of the 1980's. The first four non US airlines to order the 767 are Air Canada, ANA, El Al and Britannia. Major European airlines including Malev, British Airways, SAS, KLM, Lot, Lauda Air, Air France and Alitalia followed later, so did Uzbekistan Airways and Aeroflot.
When the Boeing 767 was introduced to the world's airlines, the FAA allowed overwater operations for twin engine aircraft, until then no twin engine aircraft was allowed to fly on overwater sectors for more than 90 minutes. TWA and El Al were the first two airlines to have their 767's approved for overwater operations. This is called ETOPS or Extended range Twin engine Overwater Passenger Service, it means that the aircraft is allowed to fly on overwater areas for up to 120 minutes, 138 minutes or even 180 minutes depending on the airframe/engine combination, each airline must have an FAA operating certificate to put the aircraft in service on overwater flights.
In the second half of the 1980's, Boeing introduced a stretched variant, the 767-300 which would seat twenty more passengers than the original 200. Japan Airlines launched the 300 variant and the 300ER was launched in the late 1980's by American Airlines, followed by Delta.

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