Abstract: An Intervention Flight Management System (IFMS) that allows a pilot to intervene in the operation of a preprogrammed flight management computer and change the speed and/or flight path of an airplane in response to air traffic control (ATC) instructions is disclosed. The IFMS includes an IFMS control panel via which the pilot interfaces with an IFMS program. The IFMS program includes intervention subroutines that override the preprogrammed instructions that control the flight management computer. The intervention subroutines include a lateral (direction) control subroutine and several vertical subroutines. The vertical subroutines include altitude, speed and vertical path subroutines. The intervention subroutines can be engaged independently of one another. Control axes unrelated to an engaged intervention subroutine remain under the control of the preprogrammed flight management computer instructions.