by James Tomayko
In a conventional aircraft, the pilot's commands are transmitted to control surfaces using hydraulic lines or other mechanical links. In a fly-by-wire aircraft, commands are converted to signals that travel over a computer network to somewhere in the vicinity of the control surface, where they are translated back into mechanical action. In effect, the pilot no longer directly controls the aircraft; rather, a computer program takes the pilot's requests into account while controlling the aircraft. This places a huge burden on the designers of the control system: it must not suffer from a general hardware or software failure during flight.
Computers Take Flight is about NASA's effort to build the first completely fly-by-wire airplane. It's not so much a story as a description of a sequence of related events; this doesn't make for particularly compelling reading. However, it's still interesting and even exciting when Tomayko describes some of the things that went wrong during flights (happily, no injuries or major damage occurred during any of the early fly-by-wire tests). Some of the best things about this book are the introduction and conclusion. The introduction is a brief history of flight, including a fascinating description of the Wright brothers' real contribution to aviation: they realized that an airplane does not have to be inherently stable, but rather, the system comprised of the plane and pilot needs to be stable. The conclusion describes the technology transition from NASA, first to the US military and then to commercial airplanes such as the Airbus 320 and Boeing 777.
copyright © 2001 John Regehr