 With "Illustrious" in refit from 1998, 820 Squadron operated out of RNAS Culdrose on anti-submarine training exercises, followed with periods embarked on ships of the Royal Fleet Auxiliary.They rejoined "Illustrious" in 1999 and participated in relief operations in Mozambique, aboard , and for Operation Palliser in Sierra Leone.Further training periods followed, as well as a Search and Rescue effort in October 2004 to aid the stricken Canadian submarine , which had been disabled after suffering a fire and flooding off the west coast of Ireland.