From the start, it appeared that the operation was running into problems. After launching from the aircraft carrier USS Nimitz (CVN-68), an unforeseen low-level sandstorm, also known as a haboob, caused two of eight helicopters to lose their way en route to Desert One, but only after men and equipment had been assembled there. A third helicopter suffered a mechanical failure and was incapable of continuing with the mission. Without enough helicopters to transport men and equipment to Desert Two, the mission was aborted. After the decision to abort the mission was made, one of the helicopters lost control while taking off and crashed into one of the MC-130s. In the ensuing explosion and fire, eight US servicemen were killed: five USAF aircrew in the MC-130, and three USMC aircrew in the RH-53. During the evacuation, six RH-53 helicopters were left behind intact.