For takeoff, an engine failure is always assumed during the takeoff run. The analysis provides the pilot a critical decision speed (V1) to establish a point during the takeoff run at which a stop/go decision can be made. If a rejected takeoff (stop) is chosen, the maximum takeoff weight (MTOW) solution ensures sufficient stopping distance for the available runway exists while also respecting other stopping constraints, such as brake energy limits. If the pilot elects to fly with one engine inoperative (OEI), the same analysis provided MTOW ensures sufficient climb capability, as well as terrain and obstacle clearance, exists along a provided flight path called the engine out procedure (EOP).
For landing, the main goals with runway analysis are to provide a maximum landing weight (MLW) that ensures sufficient climb capability in case of an OEI go-around maneuver and to prevent runway excursion during landing and stopping for a given runway surface condition. As with takeoff, additional aircraft-specific limitations are also checked.