Lateral Fly by Wire Control System Dedicated to Future Small Aircraft

Abstract

Compared to common transport aircraft (airliners), it is fact that the General Aviation (GA) sector exhibits a significant higher rate of accidents. Even though the sources are manifold, two main reasons may be identified. First, General Aviation Pilots generally have a relative low training level and small number of flight hours compared to airliner pilots and thus, their flight experience and hazard awareness is consequently limited. The second reason is, that recent transport aircraft feature a significant higher technical standard possessing various beneficial pilot assistant systems supporting the pilot to fly the aircraft safely at the same time reducing pilot’s workload extensively. The most vital assistant systems, well-known as Fly-by-Wire Flight Control Systems (FbW FCS), provide directly the appropriate control deflections according to the pilot’s commands and (measured) flight condition and thus are capable to assume important safety enhancing tasks. In addition to ensuring excellent and homogenized flying/handling qualities along the whole envelope, they offer functionalities like pilot input monitoring, provision of warnings plus active envelope protection yielding a substantial increase of passenger, crew and aircraft safety towards the key objective "carefree handling". Unfortunately, this valuable safety increase did not find its way into the general aviation sector although it is standard in current transport planes and modern business jets. This is due to the tremendous cost of typical Fly-by-Wire control technology always requiring complex redundancy and reversionary systems to fulfill the strict certification requirements. However, in order to accomplish an equivalent safety enhancement for GA aircraft and thus to diminish the high accident rates and so to protect human lives, the well-proved beneficial features of active Flight Control Systems have to be made available and affordable for them.

An essential contribution to this subject is the major objective of the ambitious Technology Research Program “Future Small Aircraft (FSA)” of the Austrian aircraft manufacturer Diamond Aircraft Industries in cooperation with the Institute of Flight System Dynamics of the Technische Universität München. Within this joint multinational research program concerning upcoming Future Small Aircraft, (amongst others) the development of an appropriate FbW lateral flight control system is expedited. Although the control law design is primarily aimed for provision of excellent handling qualities and pilot’s assistance, one main focus is also set on the elaboration of special processes, tools and hardware solutions enabling the progression of control algorithms which are perfectly tailored to the specific needs of manufacturers of small and medium-sized planes.