This AIR provides descriptions of aircraft actuation system failure-detection methods. The methods are those used for ground and in-flight detection of failures in electrohydraulic actuation systems for primary flight control. The AIR concentrates on full Fly-By-Wire (FBW) flight control actuation, but also includes one augmented-control system.

The purpose of this document is to aid the designers of the systems of the future by showing what succeeded in the past.