A method (400, 500) for an aircraft, comprising: determining (402, 502) a transition from an airplane mode to a helicopter mode for a propulsion system (110, 112) of the aircraft, wherein the propulsion system (110, 112) comprises a proprotor (120, 130), the proprotor (120, 130) comprising a plurality of rotor blades (121, 131), wherein the transition from the airplane mode to the helicopter mode comprises rotating the proprotor (120, 130) relative to a fuselage of the aircraft between an airplane mode position and a helicopter mode position; the method characterized by: determining (404, 520) whether a descent rate condition is satisfied, wherein the descent rate condition is associated with a maximum allowable descent rate for the aircraft; and controlling (406, 530) a collective pitch angle for the plurality of rotor blades (121, 131) during the transition from the airplane mode to the helicopter mode based on the descent rate condition, to limit the descent rate of the aircraft; wherein determining whether the descent rate condition is satisfied further comprises: calculating a current descent rate for the aircraft based on altitude of the aircraft; identifying an operator controlled collective pitch angle for the plurality of rotor blades (121, 131); comparing the operator controlled collective pitch angle for the plurality of rotor blades (121, 131) to an aircraft controlled collective pitch angle for the plurality of rotor blades (121, 131); and comparing the current descent rate for the aircraft to the maximum allowable descent rate for the aircraft; wherein the descent rate condition is satisfied when the operator controlled collective pitch angle is less than the aircraft controlled collective pitch angle and the current descent rate is greater than the maximum allowable descent rate. determining (402, 502) a transition from an airplane mode to a helicopter mode for a propulsion system (110, 112) of the aircraft, wherein the propulsion system (110, 112) comprises a proprotor (120, 130), the proprotor (120, 130) comprising a plurality of rotor blades (121, 131), wherein the transition from the airplane mode to the helicopter mode comprises rotating the proprotor (120, 130) relative to a fuselage of the aircraft between an airplane mode position and a helicopter mode position; the method characterized by: determining (404, 520) whether a descent rate condition is satisfied, wherein the descent rate condition is associated with a maximum allowable descent rate for the aircraft; and controlling (406, 530) a collective pitch angle for the plurality of rotor blades (121, 131) during the transition from the airplane mode to the helicopter mode based on the descent rate condition, to limit the descent rate of the aircraft; wherein determining whether the descent rate condition is satisfied further comprises: calculating a current descent rate for the aircraft based on altitude of the aircraft; identifying an operator controlled collective pitch angle for the plurality of rotor blades (121, 131); comparing the operator controlled collective pitch angle for the plurality of rotor blades (121, 131) to an aircraft controlled collective pitch angle for the plurality of rotor blades (121, 131); and comparing the current descent rate for the aircraft to the maximum allowable descent rate for the aircraft; wherein the descent rate condition is satisfied when the operator controlled collective pitch angle is less than the aircraft controlled collective pitch angle and the current descent rate is greater than the maximum allowable descent rate. determining (404, 520) whether a descent rate condition is satisfied, wherein the descent rate condition is associated with a maximum allowable descent rate for the aircraft; and controlling (406, 530) a collective pitch angle for the plurality of rotor blades (121, 131) during the transition from the airplane mode to the helicopter mode based on the descent rate condition, to limit the descent rate of the aircraft; wherein determining whether the descent rate condition is satisfied further comprises: calculating a current descent rate for the aircraft based on altitude of the aircraft; identifying an operator controlled collective pitch angle for the plurality of rotor blades (121, 131); comparing the operator controlled collective pitch angle for the plurality of rotor blades (121, 131) to an aircraft controlled collective pitch angle for the plurality of rotor blades (121, 131); and comparing the current descent rate for the aircraft to the maximum allowable descent rate for the aircraft; wherein calculating a current descent rate for the aircraft based on altitude of the aircraft; identifying an operator controlled collective pitch angle for the plurality of rotor blades (121, 131); comparing the operator controlled collective pitch angle for the plurality of rotor blades (121, 131) to an aircraft controlled collective pitch angle for the plurality of rotor blades (121, 131); and comparing the current descent rate for the aircraft to the maximum allowable descent rate for the aircraft; wherein the descent rate condition is satisfied when the operator controlled collective pitch angle is less than the aircraft controlled collective pitch angle and the current descent rate is greater than the maximum allowable descent rate.