In the ole ATPL(H) material Hydraulic Lock is described as different to Jack Stall- which if I remember correctly is a hydraulic force overload. Hydraulic Lock as I understood it from the ATPL(H) studies is a failure (design or mechanical) in which the hydraulic pressure gets around the back of the relevant actuator(s) and the controls become hydraulically 'locked'.
Definition of mourn - feel or show sorrow for the death of (someone), typically by following conventions such as the wearing of black clothes Definition of mourn - feel or show sorrow for the death of (someone), typically by following conventions such as the wearing of black clothes dictionary thesaurus
mourn. 1  to feel or express sorrow; lament; grieve. 2  to grieve for someone who has died; specif., to manifest the conventional signs of such grief, as by wearing black clothing or a mourning band. 3  to make the low, continuous sound of a dove.