Sikorsky S-61

S-61L/S-61N
A S-61N Mk.II operating for Sociedad de Salvamento y Seguridad Marítima in Spain
Role	Medium-lift transport / airliner helicopter Type of aircraft
Manufacturer	Sikorsky Aircraft
First flight	11 March 1959
Introduction	September 1961
Status	Active service
Primary users	CHC Helicopter Bristow Helicopters AAR Airlift
Number built	119[1]
Developed from	Sikorsky SH-3 Sea King

The Sikorsky S-61L and S-61N are civil variants of the SH-3 Sea King military helicopter. They were developed and produced by the American helicopter manufacturer Sikorsky Aircraft.

The commercial version of the Sea King was developed during the late 1950s. Two versions, the land-based S-61L and the amphibious S-61N, were created. The S-61L had an enlarged cabin and dispensed with some of the amphibious features, such as its float stabilizers, for greater payload capacity. It was considered attractive to utility operators, while the amphibious S-61N appealed to off-shore operators. The first models were delivered to customers during September 1961. By the turn of the century, they had become two of the most widely used airliner and oil rig support helicopters built.^[1]

Airliners were a key customer for the S-61L. Los Angeles Airways, New York Airways, and Chicago Helicopter Airways were among the first operators. However, operations in this sector proved troublesome, with profits elusive and service often subject to noise complaints and accidents.^[2][3] S-61s also saw service in the search and rescue (SAR) sector in various countries. Third-party companies have often converted individual airframes by shortening the fuselage to bolster its lift capacity. Governmental organizations have procured the S-61: the United States Department of State was a prominent operator of the type into the twenty-first century.