Immediately after a moped accident a 16-year old patient was haemodynamically unstable. Following adequate drainage of a haematopneumothorax in the hospital the patient collapsed into a shock. Thoractomy revealed a tear of the right A. pulmonalis. The hilus was clamped and a lobectomy was performed. After this the patient was haemodynamically stable; due to bone and nerve damage he was transferred to a rehabilitation centre. Laceration of the A. pulmonalis as a consequence of blunt thoracic trauma is rare and mostly fatal. In the case of a patient with a massive haematothorax rapid transport to the nearest hospital is preferable to thorax drainage at the site of the accident.