An armrest assembly (100, 300, 400), for an aircraft passenger seat, comprising: a base (102, 302, 402); a first arm (120, 320, 420) having a first end pivotally attached to the base (102, 302, 402); a second arm (130, 330, 430) having a first end pivotally attached to the base (102, 302, 402); an arm support element (108, 208, 308, 408) pivotally connected to a second end of the first arm (120, 320, 420) and pivotally connected to a second end of the second arm (130, 330, 430); and an assist device (110, 350, 410) coupled to at least one of the first arm and the second arm, the assist device applying force to at least one of the first and second arms to bias the arm support element (108, 308, 408) from a first position toward a second position higher than the first position; wherein the base (102, 302, 402), the arm support element (108, 308, 408), the first arm (120, 320, 420), and the second arm (130, 330, 430) operate together as a 4-bar linkage system wherein the first arm (120, 320, 420) and the second arm (130, 330, 430) cooperate to support the arm support element (108, 308, 408) and coordinate an angle and vertical position of the arm support element (108, 308, 408), characterized in that the base (102, 302, 402) is height-adjustable by being slidably mounted to a vertical rail (104, 310, 404) and selectively vertically positionable relative to the vertical rail (104, 310, 404) between a lowest position corresponding to a stowed position of the armrest assembly and an elevated position corresponding to a deployed position of the armrest assembly, and wherein the assist device (110, 350, 410) is further coupled to the base and is operable for applying force to the base to bias the base from a stowed forward position toward an aft elevated position. a base (102, 302, 402); a first arm (120, 320, 420) having a first end pivotally attached to the base (102, 302, 402); a second arm (130, 330, 430) having a first end pivotally attached to the base (102, 302, 402); an arm support element (108, 208, 308, 408) pivotally connected to a second end of the first arm (120, 320, 420) and pivotally connected to a second end of the second arm (130, 330, 430); and an assist device (110, 350, 410) coupled to at least one of the first arm and the second arm, the assist device applying force to at least one of the first and second arms to bias the arm support element (108, 308, 408) from a first position toward a second position higher than the first position; wherein the base (102, 302, 402), the arm support element (108, 308, 408), the first arm (120, 320, 420), and the second arm (130, 330, 430) operate together as a 4-bar linkage system wherein the first arm (120, 320, 420) and the second arm (130, 330, 430) cooperate to support the arm support element (108, 308, 408) and coordinate an angle and vertical position of the arm support element (108, 308, 408), characterized in that the base (102, 302, 402) is height-adjustable by being slidably mounted to a vertical rail (104, 310, 404) and selectively vertically positionable relative to the vertical rail (104, 310, 404) between a lowest position corresponding to a stowed position of the armrest assembly and an elevated position corresponding to a deployed position of the armrest assembly, and wherein the assist device (110, 350, 410) is further coupled to the base and is operable for applying force to the base to bias the base from a stowed forward position toward an aft elevated position.