For a while, in 1966, it looked like the end of the line for Hermes when the carrier was judged surplus to operational requirements. However, a plan to sell the warship to the Royal Australian Navy fell through.
Still with the Royal Navy, by 1971, Hermes was considered too small to operate as a strike carrier, with its fixed-wing air group being limited to the Blackburn Buccaneer, de Havilland Sea Vixen, and Fairey Gannet, and not the more modern McDonnell Douglas F-4 Phantom. At the same time, the Royal Navy was slashing its carrier force and would eventually only operate a single full-size flattop, HMS Ark Royal. As a result, the role of Hermes was switched to a commando assault carrier — equivalent to a U.S. Navy amphibious assault ship.
By 1972, the ship’s original Type 984 “dustbin” radar had been replaced by a Type 965 “bedstead” system and a new deck-lighting system added that was optimized for rotary-wing operations. The catapult and arrester wires were removed.
In its new guise, Hermes was able to accommodate a complete Royal Marine Commando unit, including a squadron of Westland Wessex assault helicopters, later superseded by Westland Sea Kings. In July 1974, Sea Kings from Hermes took part in the evacuation from Cyprus after the Turkish invasion of the northern part of the island.
Another new role beckoned in the mid-1970s when British maritime priorities switched to anti-submarine warfare (ASW). The refit of Hermes into an ASW carrier was completed in 1977, with a new-look air group typically comprising nine ASW Sea Kings and four Wessex HU5 utility helicopters. The warship retained a limited commando role, too.
The carrier then experienced another change in fortunes, as the emergence of the British Aerospace Sea Harrier short take-off and vertical landing (STOVL) strike fighter meant that Hermes was considered suitable for a return to fixed-wing operations. Another major conversion began in 1980 with the installation of a “ski jump” take-off ramp over the bow, angled upwards at 12 degrees. The flight deck was also hardened to cope with the rigors of Sea Harrier operations. A typical air group now comprised five Sea Harrier FRS1s and nine Sea Kings.
At the outbreak of the Falklands War in 1982, the Royal Navy’s new Invincible-class STOVL carriers were still in the process of introduction, but Hermes was set to be decommissioned the same year. Instead, Hermes’ superior communications fit, as well as its greater aircraft-carrying capacity, led to it being assigned as the flagship for the campaign in the South Atlantic. Hermes, therefore, headed up the task force assembled to retake the Falklands from Argentina and initially embarked 12 Sea Harriers, nine Sea King HAS5s, and nine Sea King HC4s. As the fighting continued, this was adapted to include 15 Sea Harriers, six Royal Air Force Harrier GR3s, five ASW Sea Kings, plus a pair of Westland Lynx equipped to decoy Exocet anti-ship missiles.
On May 1, 1982, Sea Harriers flying from the deck of Hermes took part in the attacks on Port Stanley, in the Falklands, where Argentine forces had captured the airfield, and Harriers from the carrier also struck the grass airstrip at Goose Green. Meanwhile, the carrier’s Sea Kings played an equally important wartime role, including ferrying Special Air Service (SAS) troops to and from the islands under cover of darkness, with the helicopter crews using experimental night-vision goggles.