Due to aviation regulations, the pilot has to don a breathing mask in some circumstances and has to be able to don the breathing mask within a five second period following an incident occurrence. Therefore, the storage unit has to be placed near the pilot. The storage unit is sometimes fastened to a wall of the cabin. Advantageously, the storage unit is mounted on a seat next to the headrest of the seat.
So, the breathing mask must be secured to the storage unit, even in severe conditions, such as very high acceleration or deceleration, due in particular to a crash, in order to prevent the breathing mask from being thrown into the cabin and possibly hitting the pilot.
Document WO 2009/007794 discloses a breathing assembly for aircraft comprising:                a storage unit to be fixed to the aircraft, having a receptacle and an opening, the storage unit further having a guiding surface extending perpendicularly to an elevation direction,        a breathing mask to be donned by an aircraft crewmember, the breathing mask comprising a rigid support having a sliding surface adapted to slide in contact with the guiding surface of the storage unit, along a sliding direction, between a storage position and an exit position, the sliding direction being perpendicular to the elevation direction, the support extends along the sliding direction between a proximal end—proximate the opening—and a distal end—at the opposite of the opening along the sliding direction—, and        a releasable securing device having a secure state and a release state, wherein when in the secure state the securing device prevents the support from sliding from the storage position towards the exit position and when in the release state the securing device allows the support to slide from the storage position towards the exit position.        