Disclosed is a mechanism for closing and locking two doors of the cowling of an aircraft engine. This mechanism includes a bolt which is received in a chamber of a receptacle. The bolt is connected to one door and the receptacle is connected to the other door so that, upon closure of the two doors, the bolt slips into the chamber. A cam attached to a rotary member housed within the chamber enables a single mechanic to close the doors and lock them snugly. This cam engages a finger on the bolt upon rotation of the rotary member which draws the bolt into the chamber by pulling against the finger. The cam moves into an over center position which securely locks the bolt in place without locking bolt travel. A locking device is additionally provided for locking the rotatable member in position when the bolt is locked in place. This locking device has a plunger which provides audible signals when the cam is in the fully opened position and when the mechanism is securely locked.