What happened to Foyle's son in the series Foyle's War?

In the series "Foyle's War," Foyle's son, Andrew, is a pilot in the Royal Air Force during World War II. Tragically, he is killed in action, which deeply affects Foyle and adds a personal dimension to his character and the storyline. Andrew's death serves as a poignant reminder of the war's toll on families and the impact of loss throughout the series.