A lubrication system comprises a reservoir for lubricant, lubricant delivery means to deliver lubricant to at least one component to be lubricated, an injector associated with each component, a control system to control the opening and closing of each injector and scavenge means to remove surplus lubricant from around each component and return it to the reservoir. They are also useful in the treatment of nervous system injury and premature labor. An inertial navigation system input of the probe receives electrical signals indicative of inertial navigation data for the aircraft.