Process and device for controlling at least one aerodynamic elevator surface of an aircraft during a takeoff. The device (1) comprises a control member (3), calculation means (5) and motor means (7) for controlling the aerodynamic elevator surface (2), as a function of an attitude angle control law received from the calculation means (5). If the duration T between the moment at which the pilot actuates the control member (3) so as to control the aerodynamic elevator surface (2) in such a way as to increase the pitch attitude angle of the aircraft and the moment at which the aircraft should reach the minimum takeoff speed is less than or equal to a nominal duration, the calculation means (5) determine and transmit a minimum control law. Otherwise, they determine and transmit a modified control law which is such that at a duration T after the actuation of the control member (3), the pitch attitude angle is substantially equal to a nominal value.

The present invention comprises a system and method for detecting icing conditions in a multi-mode aircraft by indirectly detecting ice accretion through the measurement of aircraft performance related characteristics. Indirect characteristics are used, sometimes in additional to traditional icing sensor input, because it is difficult to safely and effectively position icing sensors in aircraft that may fly in the hover mode or the fixed wing mode as well as modes in between. Typical indirect characteristics might include thrust and rotor response for a given torque. This information is compared to a model of the expected aircraft performance to determine if icing is likely to take place. For example, decreased thrust or lift for a given torque may indicate the onset of icing. Inputs from the traditional icing sensors may also be employed as additional useful, predictive data. A recursive filter having a variable gain feedback control produces an output predictive of icing conditions and provides warning information to a cockpit display as well as control signals the anti-icing equipment.

In a head-mounted display apparatus arranged to support a left-eye display system and a right-eye display system, a mounting-state confirming figure for confirming a mounting state of the head-mounted display apparatus on the user is displayed, and the displaying state of the mounting-state confirming figure on the left-eye display system and the right-eye display system is changed according to the confirmation operation on the mounting-state confirming figure.

Aircraft display symbology provides quantitative deceleration information in relation to a pilot familiar reference on a HUD system combiner. The symbology displayed includes a deceleration scale composed of a series of marks that provide a known reference for the display of deceleration information. The number of marks on the scale and the positioning and labeling of the marks can be tailored for a particular aircraft type. In a preferred embodiment, the deceleration scale is displayed along and proximal to the vertical path traveled by an aircraft acceleration symbol, which indicates the actual longitudinal acceleration or deceleration of the aircraft. The offset distance of the aircraft acceleration symbol below an aircraft reference or "boresight" symbol shows the actual (inertial) deceleration during landing rollout and rejected takeoff. The position of the aircraft acceleration symbol relative to the deceleration scale marks thereby shows the actual deceleration with respect to the reference provided by the scale. The deceleration scale is preferably displayed only when it is intended to be used--during landing rollout and during a rejected takeoff.

The invention is a real-time takeoff and landing performance monitoring system for an aircraft which provides a pilot with graphic and metric information to assist in decisions related to achieving rotation speed (V.sub.R) within the safe zone of a runway, or stopping the aircraft on the runway after landing or take-off abort. The system processes information in two segments: a pretakeoff segment and a real-time segment. One-time inputs of ambient conditions and airplane configuration information are used in the pretakeoff segment to generate scheduled performance data. The real-time segment uses the scheduled performance data, runway length data and transducer measured parameters to monitor the performance of the airplane throughout the takeoff roll. Airplane acceleration and engine-performance anomalies are detected and annunciated. A novel and important feature of this segment is that it updates the estimated runway rolling friction coefficient. Airplane performance predictions also reflect changes in head wind occurring as the takeoff roll progresses. The system provides a head-down display and a head-up display. The head-up display is projected onto a partially reflective transparent surface through which the pilot views the runway. By comparing the present performance of the airplane with a continually predicted nominal performance based upon given conditions, performance deficiencies are detected by the system and conveyed to pilot in form of both elemental information and integrated information.