This September 2008 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
Aircraft: Diamond DA-20. Injuries: 2 Serious. Location: Pueblo, Colo. Aircraft damage: Destroyed.
What reportedly happened: A CFI and student were on an instructional flight. While maneuvering to land, the airplane encountered wake turbulence from a Lockheed C-130. The Diamond went into an uncommanded descent, pitching and rolling. The pilot could not regain control before the plane hit the ground. A review of radar data revealed that the flight path of the Diamond was in an area favorable for a wake vortex encounter.
Probable cause: The student pilot’s inability to maintain control due to an encounter with wake turbulence from a larger aircraft. Contributing to the accident was the instructor pilot’s failure to intervene.
For more information: NTSB.gov
I guess they don’t know that you need to stay above and upwind of a large aircraft to avoid the wake turb.