The Indian Navy carrier, INS Viraat, R22, was originally the HMS Hermes, R12, built by the UK as a Centaur class carrier.
She was laid down in 1944, but with the end of World War II, was not launched until 1953...and ultimately not commissioned in the Royal Navy until 1959 as the HMS Hermes, R12.
As such she served with distinction in the Royal Navy until 1984. She was actually scheduled to be decommissioned in 1982, but then Argentina invaded and took the Falkland Islands. Hermes was then made the flagship of the British force sent to the south Atlantic to retake the Falklands. She served with distinction in that role...and was ultimately decommissioned in 1984.
India bought her and she was commissioned into the Indian Navy as INS Viraat, R22, on May 12, 1987.
So she has been serving in the Indian Navy now for 28 years. She served the Royal Navy from 1959 until 1984, a total of 25 years. Her total service time is now 53 years, though she herself is now 56 years old. she will add another year to that total.
By comparison, the longest serving US aircraft carrier was the USS Enterprise, CVN-65, which was commissioned on November 25, 1961 and decommissioned on December 1, 2012. She served just over 51 years.
Viraat is now scheduled to become a museum ship for India. That is good news. She will make a wonderful museum ship, like the
.
Of those five US museum carriers, the longest serving were the:
USS Lexington, CV-16: 48 years
USS Midway, CV-41: 47 years
The super carrier, USS Kitty Hawk, CV-63, served for 48 years. The nuclear carrier Nimitz, CVN-68, has been serving since 1972, a total now of 43 years.
Viraat has served longer than any of them, and, as stated, will add another year to that total before she is retired.