RAYTHEON AIRCRAFT says that it will certificate fibre-optic engine and system controls by 1998 and incorporate them in a production aircraft before 2000.
Company chairman and chief executive officer Art Wegner says that Raytheon believes that its system - named Control By Light - is practical even for single-piston types "such as the Beech Bonanza".
He told a Society of Automotive Engineers conference in the USA: "I'm not prepared to reveal yet exactly which aircraft will be the first from Raytheon Aircraft with a production Control By Light system. Our plan, however, is that it will be operating in customer hands well before 2000."
Wegner says that the initial system will be suitable for "engine controls and non-essential systems monitoring", but he adds that, for flight-controls, "...complete Control by Light is probably less than a decade away".
Raytheon's own fibre-optic programme has included extensive test-flying of a Beechjet, with the mechanical controls for one of its Pratt & Whitney Canada JT15D-5 engines replaced with a triple-fibre-optic network, actuators and "smart sensors". The aircraft was first flown in September 1993.
Wegner says that results so far suggest that a true fly-by-light, new-start, aircraft could benefit from a total airframe weight reduction "in the order of 2.5%". He explains also that the absence of mechanical linkages with their seals, bulkheads, wiring harnesses and routing-design could shave "many months" from the design time of "an all-new turbine-powered business aircraft".
He notes that, the use of fly by light technology has so far been concentrated in military aircraft and large airliners, resulting in expensive hardware - such as fibre-optic transceivers at $3,000-5,000 each. Raytheon, he says, has used in-house expertise from its Electronic Systems division at Marlboro, Massachusetts, together with cheaper, commercially available, components and a distributed, low-cost, architecture to produce a feasible system for general aviation.
Apart from the weight and design savings, benefits include greatly enhanced resistance to electrical interference, "a new crispness and consistency of flight control", more precise engine-settings and improved reliability. Wegner says that Raytheon has comfortably exceeded its one-in-a-billion target for failures over a 10h mission.
Source: Flight International