# Flight situation

The central concept related to valuation AirworthinessIt is the flight situation. The formalization of the concept of "**flight situation**'Need for reasonable use of quantitative methods in the formation and calculation of safety indicators.

Below is a variant of the flight situation that allows us to reduce the analysis to identify areas of controllability and reachability methods of the theory of optimal control, define a set of flight situations and its subsets, which correspond to the different classes of situations, and to clarify the definition of these classes. This flight is regarded as a movement of "points" in the space of situations and organize the role limitations that are imposed on the control and phase variables.

Aircraft transport system consists of several subsystems that are in dynamic interaction. Under this system, the most important link is the subsystem of "aircraft-crew environment", to maintain the safe operation of which are directed the efforts of several other subsystems.

Some of the values that make up the vector z, measured and recorded by means of objective control board (CSB) or ground-based measuring and recording systems. Vector recorded parameters denoted by y.

Parameters contained in the vector z, are random (e.g., turbulent flow velocity component). Functional dependencies which bind the parameters of z between themselves and with the components of the vector y, often random nature (eg, repair component in the process of implementing wheel control). Z and measured and recorded with random errors.

The system operates under constraints that are imposed on the components of the vector z. For convenience distinguish two types of restrictions.

Restrictions of the first type are imposed by the Flight Manual and documents that define the limits of permissible parameter changes (for example, limit alignments, payloads, speed limits, restrictions arising from the conditions of passenger comfort, permissible longitudinal or side wind speeds, etc. situations. Every time with the help of these concepts are formulated and solved the problem of constructing sets of attainability of control and taking into account relevant constraints imposed on state variables and control variables.

Modern computer modeling techniques allow pre-examine the structure of the space and expand the number of studied types of flight situations, creating the basis for more detailed analysis and forecasting of safety indicators.

If this type of aircraft, such an analysis is made, the next step is to determine the probability and transition probabilities in the space flight situations.

## Estimation of transition probability in space flight situations

The main object of study is the flight situation - space flight situations.

The flight is considered as a random process in space. There are a number of probabilistic models to describe these processes.

Adequate, formed in practice, is the model representation of discontinuous Markov processes.

Introduced in the designation of a situation or a subset of the situations time parameter indicates the starting point, which is determined with respect to the situation.