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
diurnal (comparative more diurnal, superlative most diurnal) 1  Happening or occurring during daylight, or primarily active during that time. ( 2 botany) Said of a flower open, or releasing its perfume during daylight hours, but not at night.