A manually reclinable aircraft passenger seat, comprising a tilt-recline force adjusting apparatus for an aircraft seat configured for manual tilt-recline positioning, comprising: a first spring having a first axis to urge a seat pan of the aircraft seat into a position, in which the seat pan is nearest horizontal, the first spring arranged to compress as the aircraft seat is manually reclined; a helper spring (83; 146) having a second axis parallel to the first axis, wherein the first axis and second axis are coincident, the helper spring arranged to assist or counteract the first spring; an adjustment mechanism coupled to the helper spring (83; 146) to increase or decrease a force exerted by the helper spring to assist or counteract the first spring; and a weight sensing mechanism coupled to the adjustment mechanism and operable to actuate the adjustment mechanism in direct proportion to a weight of a seated passenger, wherein the weight sensing mechanism includes a weight sensing mat, positioned in or under a seat cushion, having a strain gauge, and electronic circuitry communicatively coupled to the strain gauge configured to determine passenger weight based upon at least one signal supplied by the strain gauge, the seat comprising an actuator configured to adjust the action of the first spring, the electronic circuitry being in communication with the weight sensing mechanism and being configured to drive the actuator, a linkage pivotally connected to the actuator, wherein the weight sensing mat, the circuitry, the actuator, and the linkage are coordinated to adjust the travel of the first spring in proportional response to the weight of the seated passenger thereby increasing or decreasing the force exerted by the helper spring (83; 146), whereby the force exerted on the aircraft seat to urge the seat pan into the position in which the seat pan is nearest horizontal is greater for a heavier seated passenger than the force for a lighter seated passenger. a first spring having a first axis to urge a seat pan of the aircraft seat into a position, in which the seat pan is nearest horizontal, the first spring arranged to compress as the aircraft seat is manually reclined; a helper spring (83; 146) having a second axis parallel to the first axis, wherein the first axis and second axis are coincident, the helper spring arranged to assist or counteract the first spring; an adjustment mechanism coupled to the helper spring (83; 146) to increase or decrease a force exerted by the helper spring to assist or counteract the first spring; and a weight sensing mechanism coupled to the adjustment mechanism and operable to actuate the adjustment mechanism in direct proportion to a weight of a seated passenger, wherein the weight sensing mechanism includes a weight sensing mat, positioned in or under a seat cushion, having a strain gauge, and electronic circuitry communicatively coupled to the strain gauge configured to determine passenger weight based upon at least one signal supplied by the strain gauge, the seat comprising an actuator configured to adjust the action of the first spring, the electronic circuitry being in communication with the weight sensing mechanism and being configured to drive the actuator, a linkage pivotally connected to the actuator, wherein the weight sensing mat, the circuitry, the actuator, and the linkage are coordinated to adjust the travel of the first spring in proportional response to the weight of the seated passenger thereby increasing or decreasing the force exerted by the helper spring (83; 146), whereby the force exerted on the aircraft seat to urge the seat pan into the position in which the seat pan is nearest horizontal is greater for a heavier seated passenger than the force for a lighter seated passenger.