Thermal anti-icing of aircraft structures

An aircraft structural component comprising a forward compartment formed by a forward bulkhead and a skin structure which extends forwardly of the forward bulkhead and which has an outer surface which requires to be protected from accumulation of ice thereon, a rear compartment between the forward bulkhead and a rear bulkhead, supply duct means extending through the rear compartment and into the forward compartment for the delivery thereto of pressurised hot gases for distribution over the inner surface of the skin structure to prevent accumulation of ice on or to remove ice from the outer surface of the skin structure, protective means which surrounds the supply duct means, extends from the rear bulkhead to the forward bulkhead and forms an annular space between the protective means and the supply duct means, the annular space being closed off at its rear end at the rear bulkhead and throughout its length within the rear compartment by the protective means and being open at its forward end to provide gaseous flow communication with the forward compartment, whereby leakage of hot gases from the supply duct means upon rupture are prevented by the protective means from entering into the rear compartment and pass into the forward compartment, and discharge duct means for discharging gases from the forward compartment.