Today in Aviation History: First Flight of the Sikorsky SH-3 ‘Sea King’

On this day in aviation history, March 11, 1959, the Sikorsky SH-3 Sea King took to the skies for the first time. Known internally by Sikorsky as the S-61, the Sea King was a twin-engine Anti-Submarine Warfare (ASW) helicopter developed to counter the growing threat of Soviet submarines during the Cold War. The U.S. Navy required an advanced platform capable of detecting and neutralizing enemy submarines, and Sikorsky answered the call with a revolutionary rotorcraft.

At the heart of the Sea King’s innovation was its use of turboshaft engines—jet engines designed to produce shaft power rather than thrust, enabling efficient rotor propulsion. The aircraft was powered by two General Electric T58-GE-10 turboshaft engines, each delivering 1,400 shaft horsepower, providing enhanced performance and reliability compared to earlier piston-engine helicopters.

The Sea King was designed as an all-in-one “hunter-killer” platform, replacing the Navy’s previous method of using separate aircraft for submarine detection and engagement. Armed with up to 840 pounds of weaponry, the SH-3 could carry torpedoes, depth charges, and other specialized munitions. Entering service in 1961, the versatile helicopter quickly expanded beyond its ASW role, proving invaluable for search and rescue (SAR), transport, and medical evacuation missions.

During the Vietnam War, the SH-3 became a lifeline for downed airmen, performing high-risk SAR operations. These specially equipped Sea Kings featured self-sealing fuel tanks, additional armor, and machine guns to protect crews in hostile environments. The aircraft also played a key role in the U.S. space program, retrieving Mercury, Gemini, and Apollo capsules from the ocean after splashdown. Additionally, a modified VH-3 variant has served as Marine One, the official transport for the President of the United States, for decades.

The Sea King saw widespread adoption beyond the U.S. Navy, serving in the armed forces of Canada, Italy, Brazil, Japan, and several other nations. While retired from frontline service in the U.S. military, the Sea King continues to operate in government and military roles in India, Ukraine, and elsewhere. More than six decades after its first flight, the Sea King remains a testament to Sikorsky’s engineering prowess, proving its adaptability and endurance across a variety of missions.