Patent ID: 7530430

Claim:
A gravity controlled lubrication system for an engine of an aircraft, comprising: a. a lubricant tank for containing a lubricant therein; b. a pump having an outlet and an inlet; c. a first fluid passage for directing a used lubricant flow from a lubricant returning system of the engine to the tank during a normal flight condition; d. a second fluid passage isolated from the first fluid passage for directing the lubricant in the tank to the pump inlet during the normal flight condition; and e. a gravity controlled mechanism which includes a valve member actuated by its own weight for closing the second fluid passage to the tank and connecting the second fluid passage with the first fluid passage when the aircraft changes from the normal flight condition into an inverted flight condition, thereby a majority portion of the used lubricant flow from the lubricant returning system directly entering the pump inlet without passing through the tank.