This observational documentary series is filmed onboard the aircraft carrier HMS Illustrious during a four-month deployment. In this episode, RAF pilots practise landing on the flight deck of the aircraft carrier; engineers labour to replace one of the vessel’s gigantic engines; and a supply ship arrives to replenish Illustrious’s stock.

The mighty Illustrious aircraft carrier is nearing the end of its four-month deployment. With a crew of 1,000, this 22,000-tonne floating city – nicknamed ‘Lusty’ – is home to all manner of sailors, from stewards to engineers, officers to deckhands. The ship’s mission is to support Harrier jump jets serving in Afghanistan.

In the heat of the Indian Ocean, the pilots of the Naval Strike Wing are priming themselves for their next tour of Afghanistan. To be ready for war, the pilots have to be able to take off and land from an aircraft carrier at all hours of the day and night. RAF pilot Rich Hillard undertakes daunting nighttime landings for the first time, while the Merlin helicopter pilots get to grips with a GPMG (General Purpose Machine Gun) and practise targeting enemy boats.

The team of marine engineers faces a mammoth job this week – one of the ship’s Olympus Rolls Royce engines must be changed at sea. Fortunately, Illustrious keeps a spare onboard. Nineteen-year-old steward Rachel Wright joins the team for some work experience and gets a chance to fulfil her dream of becoming a mechanical engineer. But the heat gets too much for her and she faints on her first day.

After 67 days at sea, Lusty’s depleted stocks need replenishing. To get ten tonnes of shopping from one moving ship to another in the middle of the ocean requires a replenishment at sea, or RAS. It is an opportunity for one unhappy sailor to get some fatherly advice, as her dad works for the Royal Fleet Auxiliary ship, the Fort Austin, which has arrived to service Illustrious.

Also this week, able seaman Dan Appleby undergoes some gruelling exercises to become a Physical Training Instructor. He has his work cut out when he goes to train the sailors of the USS Cole and meets his match with the muscle-bound Master Chief Reynolds of the US Navy.