Programming

Controlled Flight Into Terrain, or CFIT, is the case of being extremely specific. It's not a mid-air collision with another aircraft, in-flight breakup or fire, flight control failure, crew incapacitation or anything like that. CFIT means the crew was present and alert, the aircraft was functioning correctly and hadn't departed controlled flight, they're flying along and all of a sudden the ground happens.

It's almost always a case of egregious amounts of pilot error. Failures in judgement such as deciding to fly down a canyon because it looked so cool when Luke Skywalker did it, and then being unable to climb out and slamming into a wall. Failure of navigation in the mountains. Failure to maintain minimum altitude on an instrument approach (Look up that Cross Air flight that killed the German pop band Passion Fruit) Failure to compute takeoff and climb performance and flying an airplane straight into the mountain off the end of the runway because you needed 900 feet per mile and at this density altitude you could only manage 750. Or, one of my favorites, the Korean Air Cargo 747 captain that chased a broken ADI straight into a forest outside London.

Crash is a broader term than controlled flight into terrain.