There are presently two principle alternatives to engine bleed air Ice Protection on mid to large size aircraft; these are known as ‘electro-expulsive’ low power and ‘electro-thermal’ systems.

Whilst electro-thermal systems can perform very successfully when provided with adequate electrical power, an electro-expulsive system can be highly energy efficient and therefore extremely attractive on platforms where generator sizing is critical or less power is available for the ice protection system.

Neither system in isolation necessarily offers an ideal IPS solution for all future wing types. The purpose of this integration study was therefore not only to investigate the integration of the IPS technologies to a Wing Slat but moreover to conceive the most appropriate combination of the technologies for Wing Slat ice protection. These ‘Hybrid’ systems had been used successfully on horizontal stabilisers on smaller aircraft types, but further work is required in the application to larger platforms and wings.

In addition to the CfP scope, GKN offered to integrate its own proven electro-thermal technology alongside the Associates’ electro-thermal and expulsive technologies to enhance the value of the integration activity and form a technology alliance to increase the probability of finding a successful solution.

In addition to functionality of the overall IPS the ‘actuation’ system aspects must be seamlessly integrated into the aircraft structure and electrical architecture. The current A320 slat was designed specifically to incorporate an engine bleed air IPS; therefore any change to this paradigm required a carefully controlled design and integration approach and thorough understanding of wing performance requirements together with structural design ability in metallic and composite materials.

The final project deliverable was a modified A320 Wing Slat incorporating a Hybrid Electrical Ice Protection System.