pitch oscilliations
Heard on radio station "Noord Holland": an eyewitness driving on the highway at the time reported seeing the aircraft making repeated and quite heavy pitch oscilliations before crashing very hard tail first.
The radio station also has people at the scene who heard from emergency workers reported that the pilots were found "slammed forward in obviously very serious condition". Inside the aircraft many passengers were found to be stuck in between seats and had to be liberated by the firebrigade.