Why did Munich air disaster happen?

There was very bad weather in Munich on the night of the accident, the 6th of February 1958. After stopping to refuel the airplane tried to take off but failed. A second attempt also failed. On a third attempt the plane hit some slush and slid off the runway, crashing through a fence. One wing hit a house and came off. The plane had been unable to build up enough speed to take off before hitting the slush.