The Yas'ur lands in Israel
In August of 1968, an IAF delegation went out to the Sikorsky plant in Connecticut, USA, to choose the IAF's next assault helicopter. The delegation was looking for a helicopter with augmented payload carry capacity, highly maneuverable and robust, that could survive direct hits from different caliber projectiles. They examined Boeing's CH-47 Chinook, and Sikorsky's CH-53. Lessons that had been learned in the Six Day War led the delegation to choose the Sikorsky.
The CH-53 was bigger and stronger than the IAF's other helicopters, and represented a new generation of assault helicopters - a leap forward in terms of rescue operations, transport missions and tactical troop landings.
In September of 1969, in the course of the War of Attrition, the first two CH-53s arrived at the port of Ashdod, and received their Hebrew name, Yas'ur. They were sent into action in short order. On August 6th 1970 the first Yas'ur squadron was established.
Operation 'Tarnegol 53'
A short time after they joined the IAF, a pair of Yas'ur CH-53s took off on an unconventional assignment: they were to "steal" a new Soviet radar from Egypt. Super Frelon choppers had landed paratroopers near the radar, at Ras 'Arb in Egypt. They subdued the Egyptian troops guarding the installation and took apart the radar. The Yas'ur CH-53s lifted the radar's components into the air and transported them, whole, to Israel, where technicians could study their secrets at their leisure.
Rescue in the Sinai
Toward the end of the War of Attrition, on June 30th 1970, a Phantom that had been on an attack mission on the Egyptian front was shot down, and its crew bailed out. The pilot, Yitzhal Pir, was taken captive. The navigator, David Ya'ir, hid and awaited his rescue. Late at night, a Yas'ur was sent to the location, found the navigator, and rescued him under heavy AA fire, despite the concentration of Egyptian forces in the area. The Yas'ur was piloted by Brig. Gen. (res.) Nehemia Dagan.
The Yom Kippur War
When the Yom Kippur War broke out, on October 6th 1973, the Yas'ur force was relocated to Refidim airbase. In the course of the war, they carried out hundereds of rescues and evacuations, and took IDF units to missions in Egypt and Syria. The CH-53s transported IDF artillery batteries, and rescued pilots and navigators who had bailed out deep in enemy territory.
On the third day of fighting, two quartets of Egyptian Sukhois and MiGs attempted to shoot down Col. Ya'acov ('Biko') Biran, who was flying a lone Yas'ur. The Sukhois identified him near Refidim road and circled above him, periodic diving into strafing runs. When they tired of this and left, a quartet of MiG-21s arrived. They also began circling the Yas'ur, but attacked in a more sophisticated way: two MiGs participated in each strafing run, with one doing the shooting and the other acting as a decoy. the Yas'ur was hit, but not shot down, and made it safely to base.
On May 10th 1977, a combined divisional exercise in the Jordan Valley was carried out, with the Yas'ur choppers transporting and landing troops. One of the Yas'ur CH-53s crashed soon after taking off. All 54 men on board were killed, including 10 air-crewmen. The tragedy is remembered as 'Ason Hanun-dalet' - 'Disaster of the 54'.
'Peace for the Galilee'
When the War in Lebanon broke out, all of the IAF's helicopters, mechanics and operations coordinators were sent to the northern front. When the fighting began, the CH-53s were a part of it - transporting a variety of equipment, ammunition and supplies, often making use of the cargo winch.
Beginning on the second day of fighting, the Yas'ur helicopters carried out a continual airlift of wounded soldiers from the front to Rambam Hospital in Haifa, and other hospitals in the north of Israel. They were the bridge between Israel and the front lines, carrying anything and everything that needed transporting: there were cargoes of shoes for the fighting men, of letters from the men to their families, and - on the Friday before the ceasefire went into effect - gallons of wine for the Sabbath. In 1983, in a redeployment operation dubbed 'Maginot Line', the Yas'ur CH-53s carried thousands of men home from the front.
Fighting the blaze on the Carmel
On September 5th 1989 the CH-53s, which had had no prior firefighting experience, were scrambled to fight the great fire which raged on Mount Carmel. They dumped 700 tons of water on the fire's centers, and succeeded in dousing it after carrying out dozens of low flyovers inside the smoke and flames. Since that time, the firefighting missions - in which the CH-53s carry 5-ton water tanks - are closely identified with the Yas'ur. Virtually every summer, the CH-53s are scrambled to fight more forest fires, that are caused by hot, dry weather, by carelessness, and by arson.
A rescue in Sudan
On November 8th 1992 a pair of CH-53s rescued the passengers of the Israeli yacht 'Fantasy 2', that had run ashoal off the shores of Sudan. En route, a pair of Hercules transports refueled the CH-53s in midair. It was one of the longest-ranged sea rescue operations in the history of the IAF.
The 1997 Yas'ur Catastrophe
On the night of February 4th 1997, two Yas'ur helicopters that were carrying soldiers to Lebanon collided over Shea'r Yashuv, in northern Israel. All 73 soldiers and crewmen on board were killed. It was the heaviest disaster in the IAF's history.
A commission of inquiry appointed to investigate the crash could not determine the reason for the crash with absolute certainty, but it is almost certain that it was caused by human error, as a result of loss of eye contact between the two helicopters.