Abstract: A manually-operable lock for releasably securing a canopy 10 in closed condition characterized by a pair of dogs 28 mounted in fore-and-aft alignment on the wall of the cockpit of an aircraft, a pair of dog receivers 16 mounted on the canopy in juxtaposition with the dogs when the canopy is in its closed condition, a dog-actuating arm 32 including internal and external arm components 34 and 36, respectively, supported for oscillation about a common axis and pivotally connected to the dogs through a pitman rod 30 for pivotally displacing the dog, a spring-loaded pin 50 mounted on the arm and adapted to be ramp-cammed and positioned in coaxial alignment with a receiving bore 52, when the arm is at the limit of its forward throw, and pin-release means including external and internal components 66 and 60, respectively, for releasing the arm for pivotal displacement.