The S-55, whose first flight took place on November 10, 1949, was the world's first certified transport helicopter, with both the power and capacity to carry large loads. It was also the first helicopter to fly the Atlantic and the first to be equipped with anti-submarine sonar and torpedoes. A total of 1,100 examples were built in the U.S. while a further 550 examples were built elsewhere. The S-55 also took an important part in U.S. operations during the Korean war.
The first two Israeli S-55s arrived in Israel shortly before operation "Kadesh" (the Suez campaign) in late 1956, but did not take any part in the fighting. Although helicopters of the same type were used by the British and French during their seizure of the Suez Canal, the IAF made no use of the type until the fighting had ended. Six more S-55 were purchased for the IAF in 1958 following the Suez campaign and the subsequent requirement for a troop transport. The helicopters also served as Search and Rescue (SAR) aircraft but were soon replaced by the Sikorsky S-58 when their engines proved unsuitable for Israel's humid climate. The type continued to fly maritime missions until it was finally retired from IAF service in 1963.
Sources: IAF Inventory