Fly-by-optics is sometimes used instead of fly-by-wire because it can
transfer data at higher speeds, and it is immune to electromagnetic
interference. In most cases, the cables are just changed from electrical
optic cables. Sometimes it is referred to as "Fly-by-light" due to
its use of Fiber Optics. The data generated by the software and
interpreted by the controller remain the same.
Having eliminated the mechanical transmission circuits in fly-by-wire flight
control systems, the next step is to eliminate the bulky and heavy hydraulic
circuits. The hydraulic circuit is replaced by an electrical power circuit. The
power circuits power electrical or self-contained electrohydraulic actuators
that are controlled by the digital flight control computers. All benefits of
digital fly-by-wire are retained.
The biggest benefits are weight savings, the possibility of redundant power
circuits and tighter integration between the aircraft flight control systems and
its avionics systems. The absence of hydraulics greatly reduces maintenance
costs. This system is used in the Lockheed
Martin F-35 and in Airbus
A380 backup flight controls. The Boeing
787 will also incorporate some
electrically operated flight controls (spoilers and horizontal stabilizer),
which will remain operational with either a total hydraulics failure and/or
flight control computer failure.
Wiring adds a considerable amount of weight to an aircraft; therefore,
researchers are exploring implementing fly-by-wireless solutions.
Fly-by-wireless systems are very similar to fly-by-wire systems, however,
instead of using a wired protocol for the physical
layer a wireless protocol is
In addition to reducing weight, implementing a wireless solution has the
potential to reduce costs throughout an aircraft's life cycle. For example, many
key failure points associated with wire and connectors will be eliminated thus
hours spent troubleshooting wires and connectors will be reduced. Furthermore,
engineering costs could potentially decrease because less time would be spent on
designing wiring installations, late changes in an aircraft's design would be
easier to manage, etc.
Flight Control System
A newer flight control system, called Intelligent Flight Control System (IFCS),
is an extension of modern digital fly-by-wire flight control systems. The aim is
to intelligently compensate for aircraft damage and failure during flight, such
as automatically using engine thrust and other avionics to compensate for severe
failures such as loss of hydraulics, loss of rudder, loss of ailerons, loss of
an engine, etc. Several demonstrations were made on a flight simulator where a Cessna-trained
small-aircraft pilot successfully landed a heavily-damaged full-size concept
jet, without prior experience with large-body jet aircraft. This development is
being spearheaded by NASA Dryden
Flight Research Center. It is
reported that enhancements are mostly software upgrades to existing fully
computerized digital fly-by-wire flight control systems.