Product Code:SAE ARP4148 Title:Gas Turbine Engine Real Time Performance Model Presentation for Digital Computers Issuing Committee:S-15 Gas Turbine Perf Simulation Nomenclature And Interfaces Scope: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 trransient 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.Product Code:SAE AS1105 Title:Service Time Coding of Propulsion Engine Items (NONCURRENT Jul 1991) Issuing Committee:E-25 General Standards For Aerospace And Propulsion Systems Scope:To establish a standard for service time code markings on items in propulsion engines where such marking may be required for determining accumulated service time and remaining life expectancy.