EU Project: Simulation of UPset Recovery in Avaition
The high safety standards in aviation make flying the safest way of transportation. By learning from incidents and accidents flight safety remains to be improved. Currently the focus is on loss of control in-flight (LOC-I). In-flight events show that an aircraft may suddenly enter an "upset", i.e. an unusual attitude or stall. Although upset events are extremely rare, flight crews have to recognize the condition and act swiftly to ensure safety of the flight. In order to familiarize pilots with such situations and provide them with a toolset for successful recovery, flight simulators need to accurately reproduce upset regimes. As current training simulators are limited to normal flight conditions, SUPRA is developing new methods for reproduction of aircraft behavior in upset situations and advanced concepts providing the pilot with the unusual forces present in abnormal situations.
Upset situations may take the aircraft out of its normal operational envelope, altering its normal response to control inputs by the flight crew. Mathematical aircraft models currently used in commercial flight simulation are typically validated within the normal flight envelope only. Hence, The SUPRA project needs to extend these models to cover the extreme aerodynamics representative for out-of-the-envelope aircraft behavior. Using a unique engineering approach, including predictive methods, such as computational fluid dynamics, SUPRA developed an add-on model in order to familiarize pilots with the effects of unsteady non-linear aerodynamics at the edge of the flight envelope. An improved operator station allows the instructor to monitor if, and how much, the pilot deviates from the safe flight envelope, and whether recovery is adequate. The SUPRA upset scenarios can be considered an advancement of the Industrial Airplane Upset Recovery Training Aid, by including a developed stall.
Motion cueing and G-forces
Another objective of SUPRA is to push the simulator motion envelope. Current simulators use a hexapod moving base, controlled by classical motion cueing software that applies for a wide range of pilot training scenarios, but has clear limitations for the simulation of the large angular rates, un-coordinated flight and sustained accelerations associated with upset recovery. Within SUPRA alternative motion cueing strategies are investigated to make more efficient use of the motion space of the hexapod simulators of NLR and TsAGI, for example by prepositioning the cabin for a larger linear stroke. Whereas a hexapod is inherently limited to 1g, SUPRA also investigates the usefulness of the centrifuge-based simulator DESDEMONA at TNO, capable of unlimited rotations, 8m linear motions, and centrifugation up to 3g. This provides pilots with the actual feel of G-loads. Preliminary results show that inexperienced pilots are hesitant to pull the G-loads required for efficient upset recovery.