adjusted again when the first plane was assembled. In the 777 design process, on the other hand, a sophisticated CADD system was used; the use of this system eliminated the need for most of the mockups, and the first 777 aircraft assembled could actually be flown. This system included two components. The first was Computer Graphics Aided Three-D Interface Application (CATIA), which was used to design every part. The second was Electronic Pre-Assembly In the Computer (EPIC), which was used to ensure that each designed part would fit properly with all of the other parts in the aircraft; the software discovered where, for example, a particular structural component would interfere with hydraulic lines. The CAD system allowed engineers to communicate their designs with each other across design-build teams to make sure that designs, as they were developed, were compatible with each other. Not only was computer technology essential for the design of the 777, it is essential for the 777 control system, which is computer-based. In previous Boeing airliner designs, the pilots’ controls were connected by cables to hydraulic actuators that caused control surfaces to move. In contrast, in the 777 design, the pilots’ control movements are input to a computer system which determines electrical signals to send over wires to actuators. This fly-by-wire system saves significant cost and weight, but requires sophisticated and reliable computer systems to control the plane in response to the pilots’ inputs. The fly-by-wire system allows the 777 to be flown by a crew of only two (a pilot and a copilot); without the system, a much larger crew would be required. Figure 31 shows the cockpit of the Boeing 777. Development of the 777 fly-by-wire system required writing and debugging millions of lines of computer code.
Figure 6.31: The cockpit of the Boeing 777. Note that most flight information is displayed on several computer operated displays. www.ck12.org
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