The Israeli Air Force has grounded its fleet of ageing Yas’ur transport helicopters after the engine of one caught fire Tuesday night.The military is investigating the emergency landing of a Yas'ur helicopter after its engine caught fire, completely destroying the aircraft.It was a “significant accident” due to a technical malfunction in the engine, a senior Israel Air Force officer said Tuesday night shortly after the incident, crediting the pilot’s quick response with saving the lives of all on board.While the helicopter was completely destroyed in the blaze following the emergency landing outside the community of Beit Kama in the northern Negev desert, all 11 soldiers from the elite Shaldag commando unit and two pilots onboard the aircraft made it out unhurt.“We were notified of a helicopter fire west of Beit Kama," local fire chief Avi Arush said. "As this was a complicated situation, additional firefighting teams were called to the scene. When we arrived, we all worked to put out the fire and to look for anyone trapped inside. Luckily, the occupants of the helicopter made it out intact and healthy before we arrived at the scene,” he said.The helicopter was one of three en route to a base in southern Israel for a training exercise and was flying at a height of 170m. when the third aircraft notified the pilots of the fire in the engine. The pilots carried out the emergency landing within a minute of the fire breaking out.The IDF said the engine fire was the result of a “technical malfunction,” and will be investigating exactly what caused it.First used by the IAF in 1969, the Yas’urs are the air force’s primary helicopter, used regularly to transport soldiers and equipment. They have also taken part in a wide variety of missions, including secret operations as well as search and rescue missions. While the aging helicopters have been upgraded with 20 new electronic systems and with missile defense, the IAF will still need to replace them by 2025 when they will be more than 50 years old.A senior Air Force officer said that while the platform was one of the older platforms, the engine was not.“We are currently deciding which platform can replace the Yas’ur” he said. “We didn’t need this incident to show us the need to replace the platform.”In March, the annual State Comptroller report recommended that the IAF replace the aging aircraft as soon as possible, because “prolonging the life of the Yas’ur is liable to endanger human life, and may have significant operational implications and substantial maintenance costs.”The air force should “consider purchasing the Yas’ur replacement option early so that it will be as close as possible to the date on which the memorandum of understanding with the United States is implemented,” the report added.The IAF plans to buy some 20 new heavy-lift helicopters – in other words, an entire squadron – to replace the current CH-53 Sea Stallion squadron at the Tel Nof Base. The two options in the running are Lockheed Martin Sikorsky’s CH-53K King Stallion, the same maker of the Yas’ur, and Boeing’s Ch-47F Chinook helicopter.But the longer it takes to sign a contract to replace the Yas’ur, the possibility of a failure in the platform increases. “A helicopter crashing with so many soldiers would be a strategic catastrophe for Israel,” a defense industry source told The Jerusalem Post in September.