On 26 July 2010, an Israeli Air Force Sikorsky CH-53 Yas'ur helicopter crashed during a training flight in the Carpathian Mountains, near the city of Brașov in Romania.

[3] The exercise was known as Blue Sky 2010, which was supposed to last for 11 days, and in which the Romanian and Israeli troops practiced flying at low altitudes in difficult terrain for search-and-rescue missions and medical evacuations.

[4][5] The Yasour transport helicopter, (Sikorsky CH-53), is considered by Israel to be the most reliable aircraft of its kind in the IDF, and has been used for over 40 years.

In 2007, under a program called "Yasour 2025," intended to extend the Yasour's life until 2025, the IAF installed over 20 new electronic systems, including, for the first time on helicopters, one for missile defense,[3] On 26 July 2010 at 1:15 p.m., two Yasur helicopters took off from the Romanian Air Force Base in Boboc and headed north toward the Carpathian Mountains.

[1][2] The Romanian authorities declared the area around the crash site a closed military zone and sent police and security forces into the mountain the morning after the accident.

Immediately after learning of the accident the Air Force Commander Maj. Gen. Ido Nehoshtan appointed an investigative team to look into the causes of the crash, headed by Brigadier-General Shlomo Mashiach.

[16] All flight exercises were halted by IAF commander Maj. Gen. Ido Nechushtan for a day, in order to conduct safety inspections.

[19] Cooperation between Israel and Romania increased following the crash, and Romanian Air Force Deputy Commander General Alexander Glushka said that "In the past year, the friendship between us has become a brotherhood.

I want to thank he Romanian air force and army for their assistance after the tragedy that occurred, and to assure them that our cooperation and partnership will continue.

[22]In September 2011, IAF chief Major General Ido Nehushtan led a service with his Romanian counterpart in memory of those killed during the crash.

[23] In November 2011, the Tel Nof base of the Israeli Air Force received an ancient 200-year-old Torah, one which had survived the Holocaust, as a donation from Romania's Jewish community in commemoration of the victims of the Sikorsky CH-53 crash.

A special ceremony marked the occasion for the receiving of the scroll, which was found in Romania in the cellars of the previous Romanian leader Nicolae Ceaușescu.