Abstract: An loader is provided that has a body which is pivotable in a mid-section, a primary linkage pivotally mounted to the body, a secondary linkage pivotally mounted to the primary linkage, and a grapple pivotally mounted to the secondary linkage to carry a load positioned forward of the body. The improvement includes means for determining the positions of the primary and secondary linkages, and means for measuring the weight of a load being carried by the grapple. The control system has the capability of receiving from the means the positions of the primary and secondary linkages and the weight of the load and calculating whether the load is in an unstable position. If the load is unstable, the operator is prevented from moving the load to a more unstable position, but is not prevented from moving the load to a more stable position.