[inferno0069]

From the article: it "was flying at 2,000 feet".

I see no reason to assume it would have any ground-avoidance software besides flying higher if it detects it's near the ground.

[Groxx]

And when something's glitching? Say an avoid-ground routine and a go-down routine, plus some sort of importance measurement (very near ground? go up fast). All reasonable in a self-piloting machine.

Now say the go-down routine gets abnormally high importance, or fires off a million times per second.

Unlikely? Yes, but so is what happened. And I specifically included "consider if", because it's not what happened, but could conceivably, and was probably one of the panicked fears going through their heads.

[ra]

Even small private aircraft have GPS chart plotting terrain avoidance these days