The objective of the NASA Aviation Safety Program is to improve the safety of current and future aircraft operating in the National Airspace System. Research under this program has focused on vehicle design, construction, operation and maintenance. Reducing aircraft loss of control accidents is critical to increasing aviation safety as it is the largest and most fatal aircraft accident category...

Loss of control (LOC) occurs when an aircraft motion departs from the typical flight envelope. Loss of control events have been a contributing factor in numerous commercial airline accidents. Hence there has been interest in rigorously defining and quantifying the characteristics of LOC. One major issue is that LOC is rare and hence there is limited flight data for these events. This limits the...

The flight envelope can be viewed as a set within the state space of an aircraft. For various safety considerations an aircraft is required to remain within its prescribed flight envelope. The safe set is the largest controlled invariant set within the flight envelope. Thus, if an aircraft is to remain within its envelope it must stay within the safe set. When an aircraft is impaired, e.g., a j...

Research into previous flight accidents and investigations of the fault-tolerant flight control (FTFC) strategies used suggest that an aircraft, under many post-failure circumstances, can still achieve a certain level of flight performance using the remaining valid control effectors. However, the control authority or the safe flight envelope of the aircraft will inevitably shrink due to structu...

A novel control scheme, fuzzy immune adaptive model inversion control, was put forward, aiming at the large flight envelope curve control problem of helicopter. The proposed scheme was designed based on model inversion theory, biology immune response mechanism and fuzzy control method. It could achieve effective control throughout large flight envelope curve via the design of fuzzy immune onlin...

The status of an ongoing project to identify a full-envelope model of the YAV-8B Harrier using flight-test and parameter identification techniques is described. As part of the research in advanced control and display concepts for V/STOL aircraft, a full-envelope aerodynamic model of the YAV-8B will be identified. Mathematical model structures and parameter identification methods that are being ...

Formal robustness analysis of aircraft control upset prevention and recovery systems could play an important role in their validation and ultimate certification. Such systems developed for failure detection, identification, and reconfiguration, as well as upset recovery, need to be evaluated over broad regions of the flight envelope or under extreme flight conditions, and should include various...

Despite a wealth of evidence demonstrating extraordinary maximal performance, little is known about the routine flight performance of insects. We present a set of techniques for benchmarking performance characteristics of insects in free flight, demonstrated using a model species, and comment on the significance of the performance observed. Free-flying blowflies (Calliphora vicina) were filmed ...

Loss-of-Control (LOC) is a major factor in fatal aircraft accidents. LOC is generally associated with flight outside of the normal flight envelope almost always involving nonlinear behaviors and often including extreme attitude conditions. Recent and ongoing work at the NASA Langley Research Center has focused on building aerodynamic models adequate for simulation and analysis in these regimes....