The MasterChef semi-finals continue with a spectacular challenge as the eight remaining cooks head to Lincolnshire for an event they will never forget. They must cook a 50th anniversary celebration lunch for some of the most well-loved members of the British armed forces - 90 pilots and the support crew of the Red Arrows. Split into two teams of four, for the first time the semi-finalists have to run their own kitchens in specially constructed catering tents beside the Red Arrows' main runway. As they cook with the Red Arrows practising their daredevil moves over their tents, will the contestants be able to rise to the challenge and produce a lunch worthy of the occasion? With less than four hours to create 100 plates of food, organisation and teamwork is essential for success. It's vital the two teams perform at their absolute best because after judging their food, John and Gregg pick the weakest team to return to the MasterChef kitchen, where they must cook off against each other in a special palate test. Here they must rely on their sense of smell and palate to decipher exactly what's in a dish cooked by John - before having to replicate the dish themselves. With one more contestant going home after this, the fight is on to stay in the competition and take another step towards being crowned MasterChef Champion 2015.