LONDON—The British Army Air Corps has marked the impending retirement of its locally assembled Apache attack helicopters with a flypast around the UK.

Four of the Apache AH1s—formerly built by AgustaWestland, now Leonardo—made flypasts at around 15 locations associated with the attack helicopter on March 25, prior to the type’s formal withdrawal from service.

The Apache AH1, a UK-modified version of the AH-64D using the Safran-made RTM322 engine, is being retired after 23 years of service and replaced by re-manufactured AH-64Es supplied directly from Boeing through the U.S. Foreign Military Sales program.

The UK milestone emerges as the U.S. Army marks 40 years since deliveries of the first AH-64A Apaches in early 1984.

The Aviation Week Network Fleet Discovery database show that the British Army has taken delivery of 36 of its planned fleet of 50 AH-64Es.

Most of the 67 AH1 models purchased have been dismantled and components reused as part of the re-manufacturing process.

The British Army’s AH1s have been extensively used in operations, including in Afghanistan and Libya—which saw them operate from a Royal Navy helicopter carrier, HMS Ocean.

Army commanders declared the AH-64E as ready for operations in October 2023, and all 50 should be in service by 2025.

As well as being equipped with the RTM322 engine, the Apache AH1 features a range of UK-specific equipment, health and usage monitoring systems and weapons.

Officials say that by transitioning to the General Electric T700-701D-powered AH-64Es, the British Army will benefit from a logistics chain that supports a larger worldwide fleet, an extensive update roadmap and the ability for the UK to work more closely with its U.S. counterparts on the battlefield—using the same forward refueling and arming points, something commanders said was difficult with the previous model.

Other European countries are joining the UK in fielding the AH-64E, including the Netherlands, which recently began the first domestic training flights of its AH-64Es. Poland also has the type on order.