Method of automatically triggering an emergency buoyancy system for a hybrid helicopter

An emergency buoyancy system for an aircraft having a fuselage and two half-wings situated on either side of the fuselage, the emergency buoyancy system comprising:

• at least one main inflatable bag suitable for being arranged under the fuselage;
• at least one secondary inflatable bag suitable for being arranged under each half-wing;
• a plurality of immersion sensors for determining the beginning of the aircraft ditching;
• at least one retractable wing undercarriage arranged under each half-wing and moveable between a retracted position to a deployed position, each retractable wing undercarriage provided with at least one of the plurality of immersion sensors;
• priming means for priming said emergency buoyancy system;
• anticipation means for determining whether there is a risk of the aircraft ditching;
• deployment means for deploying each wing undercarriage if the risk of the aircraft ditching is determined by the anticipation mean;
• a trigger connected to the priming means to order the inflation of the inflatable bags;
• and
• an inflation system having at least one fluid generator for inflating the inflatable bags, the inflation system being connected to the trigger
• wherein the retractable wing undercarriage has a deployed height being greater than a radius of a propulsive propeller disposed on each of the two half-wings, wherein the at least one immersion sensor is disposed below the propulsive propeller when the retractable wing undercarriage is in the deployed position.

A hybrid helicopter comprising:

• a fuselage;
• a main rotor situated above the fuselage;
• two half-wings situated on either side of the fuselage;
• at least one propulsive propeller disposed on each half-wing;
• at least one retractable wing undercarriage arranged under each half-wing and moveable between a retracted position to a deployed position;
• and
• an emergency buoyancy system, wherein the emergency buoyancy system comprises:
• a main inflatable bag arranged under the fuselage;
• a secondary inflatable bag arranged under each half-wing;
• at least one immersion sensor disposed on each retractable wing undercarriage for indicating a beginning of the helicopter ditching,
• wherein the emergency buoyancy system inflates the main and secondary inflatable bags when the immersion sensor indicates the beginning of the helicopter ditching;
• wherein the retractable wing undercarriage has a deployed height being greater than a radius of the propulsive propeller, wherein the at least one immersion sensor is disposed below the propulsive propeller when the retractable wing undercarriage is in the deployed position.