Government authorities say a preliminary investigation into the fatal crash of a Swiss fighter jet shows crews on the ground had instructed the doomed pilot to fly at an inappropriately low altitude.

The Swiss government said Tuesday that the 27-year-old pilot took off from nearby Meiringen air base relying on the instrument panel, not eyesight, because of cloud cover.

Ground control operators instructed him to ascend to 10,000 feet (about 3,050 meters). His U.S.-built F/A-18C aircraft crashed in the Alps of central Switzerland at an altitude of roughly 3,300 meters.

Investigators say there is no evidence the jet experienced technical problems.

The investigation isn't looking into possible wrongdoing by any individuals so far.