The disclosed embodiments relate to an aircraft having an in-flight leveling system for a seat onboard the aircraft that includes a swivel mechanism providing selective rotational movement of the a rear portion of the seat to compensate for an angle of inclination of the aircraft during flight. A locking mechanism is coupled to the swivel mechanism to retain the seat in a first position for use on the ground and a second position for use during flight. An actuator moves the locking mechanism between a locked condition and an unlocked condition permitting the seat to move between the first position to the second position enabling the seat to be substantially level when the aircraft is on the ground and during flight.

In a preferred embodiment, a tilt-recline force adjusting apparatus for an aircraft passenger seat configured for a tilt-recline positioning includes a first spring having a first axis to urge a seat back into an upright position, the first spring arranged to compress as the seat is manually reclined, a helper spring having a second axis parallel to the first axis, the helper spring arranged to assist or counteract the first spring, an adjustment mechanism coupled to the helper spring 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, whereby the force exerted on the aircraft seat to urge the seat back into an upright position is greater for a heavier seated passenger