TRIPLEX DIGITAL FLY-BY-WIRE REDUNDANCY MANAGEMENT TECHNIQUES

Operational fly-by-wire (FBW) systems, w hether analog or digital, are today mostly quadruplex. The introduction of digital computers into FBW systems presents the possibility of reducing the redundancy level from quadruplex to triplex (even, in some cases, duplex) with attendant system benefits: reduction in maintainability, size, weight, power, and cost. Quantitative data is introduced to show the failure coverage needed to achieve acceptable system reliability. Redundancy management techniques are presented, their failure coverage d etermined, and an analytical link established between these techniques and system reliability. The conclusion is that a triplex system is both desirable and achievable.