sentences:  Ahrens AR 404
  
  The Ahrens AR 404 was a prototype American civil transport aircraft first flown in 1976, a high-wing monoplane powered by four turboprop engines.In order to facilitate the loading and unloading of cargo, the fuselage was of constant rectangular section along almost its entire length, the main undercarriage was retracted into sponsons on the fuselage sides, and the tail included a loading ramp.