A very hard landing during the certification test of the MD-80. It happened at Edward's Air Force Base in California, USA in 1980.
The McDonnell Douglas flight test crew was trying to demonstrate horizonal distance required to land and bring the aircraft to a full stop. Aparently, when the aircraft came to a stop, the crew was not aware that the tail had broken off.
Depending on how interested you are in the details, the accident report can be downloaded here:
