A device for indicating that an airplane has reached a safe speed in the presence of headwinds for initiating take-off rotation. The device senses the true ground speed of the airplane and converts the true ground speed into an "indicated ground speed" in accord with the relationship between true air speed and indicated air speed for the airplane. The device subtracts the indicated ground speed from the indicated air speed of the airplane to determine the amount of the headwind and, whenever the headwind exceeds a preselected margin, the device increases the value of the safe minimum indicated air speed for initiation of take-off by any excess of the headwind over the preselected margin. The device then directs the flight director to initiate take-off rotation when the indicated air speed of the airplane equals or exceeds the adjusted minimum indicated air speed.

A warning system provides a warning to the pilot of an aircraft during a take-off mode of flight of a relatively dangerous flight condition, such as improper configuration of the flaps during a take-off mode of flight prior to the aircraft becoming airborne. In order to avoid nuisance warnings, the warning system is disabled once the aircraft becomes airborne. The warning system monitors the flap position of the aircraft as well as the airspeed and provides a warning when the flaps are improperly configured during a take-off mode of flight. Different aural warnings are provided as a function of the airspeed of the aircraft.

The displays are provided for assisting a pilot in making critical decisions during the takeoff roll of the aircraft. The first of the displays includes four pointers which indicate, respectively, the maximum available acceleration of the aircraft, the minimum acceleration required to achieve a velocity V.sub.2 at 35 feet above the end of the runway with all engines operating, the minimum required acceleration which will allow the aircraft to accelerate to a critical velocity with all engines operating and complete a legal takeoff after loss of an engine at the critical velocity (V.sub.1), and the actual acceleration of the aircraft. The second display indicates the ability of the aircraft to safely complete the takeoff if an engine were to fail and the ability of the aircraft to stop safely if the pilot were to decide to abort the takeoff. The second display includes first and second sets of colored lights indicating clearly safe and unsafe conditions and a marginally safe condition for the continued takeoff and abort situations. The displays are driven by a microprocessor which is supplied with both specific and generalized data for the aircraft such that the variety of factors to be displayed can be calculated.