Water-impact force calculation and analysis for aircraft over sea contacted by waves

When modern aircrafts above water flying over sea in a very low height, the flight height is limited by the sea state. Bad sea state can not only cause the attitude overturning and dropping into the water, but also break the aircraft structure through the water-impact force, therefore the safety problem of aircraft should be considered. In this paper, the water-impact force of a typical symmetrical aircraft flying above sea is researched. Based on the water-impact force model, an analysis on the force related to trajectory angle and equivalent pitch angle is presented. Also the water-contact condition, which is due to the water-impact overload limitation, to make sure aircraft contacted by waves safe without attitude overturning and structure broken, is proposed.