This SAE Aerospace Recommended Practice (ARP) provides guidance for the presentation of gas turbine engine transient performance models with the capacity to be implemented as digital computer programs operating in real time and is intended to complement AS681.

Such models will be used in those applications where a transient program must interface with physical systems. These applications are characterized by the requirement for real time transient response.

These models require attention to unique characteristics that are beyond the scope of AS681. This document is intended to facilitate the development of mathematical models and the coordination of their requirements with the user. It will not unduly restrict the modeling methodology used by the supplier.

The objective of this document is to define a recommended practice for the delivery of mathematical models intended for real time use. Models used in this application may also be contained in deliverable computer programs covered by AS681.

Mathematical Model Presentation:

The presentation of mathematical models can include, but is not limited to, the following:

a. Executable computer programs

b. Program listings

c. Block diagrams

d. Tabular data

e. Plotted data

A description of the model will be included in the Model Implementation Guide (6.2, Items 4 and 10).

Applications:

The applications of real time engine models include, but are not limited to, the following:

a. Flight simulators

b. Avionic and control system development

c. Control system embedded software