Sikorsky HH-52 Seaguard

The Sikorsky HH-52 Seaguard (company designation S-62) is an early amphibious helicopter designed and produced by American helicopter manufacturer Sikorsky Aircraft. It was the first of the company's amphibious rotorcraft to fly and the United States Coast Guard's first turbine-powered helicopter and first amphibious helicopter.

The S-62 was originally developed as a commercial venture during the late 1950s. It combined the dynamic elements of the Sikorsky S-55 with a boat hull-shaped fuselage and a single lightweight turboshaft engine. The prototype S-62 conducted its maiden flight on 22 May 1958, powered by a single General Electric T58-GE-6 turboshaft engine. It underwent evaluation at the Naval Air Test Center in Patuxent River, Maryland, at Sikorsky's own expense as part of its effort to promote the S-62 to the United States Coast Guard (USCG).

The USCG would procure 99 S-62s, which it initially designated as the HU2S-1G Seaguard, and later redesignated as the HH-52A Seaguard. It was primarily operated by the USCG for air-sea rescue missions. Various other operators opted to procure the S-62 for their own purposes, from airliners to utility transporters, and foreign air services. It was widely used into the 1980s, when many operators elected to replace the type with newer rotorcraft. The HH-52 was withdrawn from USCG service during 1989 in favor of nonamphibious rotorcraft, such as the Eurocopter HH-65 Dolphin, which rely solely on the use of a winch from a low hover to conduct rescue operations.