Hardware-in-the-loop evaluation of a quick-start system for helicopter gas turbine OEI operations tested in simulated flights

Abstract

This paper first outlines a hardware-in-the-loop environment for helicopter flight simulations with a real turboshaft engine. The setup uses an Allison 250-C20B engine equipped with a pneumatic impingement system, named as Quick-Start System (QSS). The hardware-in-the-loop engine and the QSS are connected to the Rotorcraft Simulation Environment (ROSIE), a fixed-based pilot-in-the-loop rotorcraft simulator. In parallel, a visual and audio augmentation system based on a standard helicopter head-down instrumentation and a future-proof multimodal cueing concept is used for pilot workload and handling qualities investigations. Next, the paper covers the design and proceeding of a hardware-pilot-in-the-loop simulator flight test campaign along ADS-33 PRF flight test standards conducted together with five helicopter test and fleet pilots from German Armed Forces. Finally, the paper reports the results of piloted simulation tests of different mission task elements (MTE), embedded to a wide spectrum of helicopter Intended Single Engine Operation (ISEO) and One Engine Inoperative (OEI) operations, where different levels of the QSS and the augmentation concepts had been evaluated by the participating pilots. Results indicate a pilot workload level of Bedford rating level 1 and an enhanced situational awareness with the assistance of visual and audio augmentations. Moreover, the QSS enabled all pilots to recover the helicopter with acceptable loss of altitude at acceptable handling qualities and pilot workload.