Raisable landing gear having a shortenable leg

Raisable landing gear having a shortenable leg, including a leg hinged to the structure of an airplane, the leg being constituted by a strut housing a shock absorber mainly constituted by a sliding rod and by a shock absorber plunger rod, together with a linkage connecting said plunger rod to the strut and under the control of a resilient connecting rod having a threshold and fixed to the structure of the airplane, in such a manner as to pull the block absorber while the leg is being raised and to push said shock absorber while said leg is being lowered, wherein the linkage includes two arms forming an alignment, with a first arm hinged on the plunger rod of the shock absorber and having a lateral appendix whose free end is capable of co-operating with a stationary cam integral with the structure of the airplane, and a second arm hinged to the strut, together with a lever constrained to rotate with said second arm and connected to the threshold connecting rod, said lateral appendix and said stationary cam being organized to act in an emergency to ensure that the shock absorber is extended and that said shock absorber is locked in the undercarriage-down position.