Patent ID: 8725322
Filing Date: 2014-05-13
Classification: G01C,G05D

Abstract:
1. A method for updating a target altitude for an emergency descent of an aircraft with a target updating device on board the aircraft, the target altitude representing the altitude to be reached by the aircraft at the end of the emergency descent, the method comprising: (a) determining, with a target security altitude determination device included in the target updating device, a target security altitude as a function of the emergency descent, by automatically and repeatedly carrying out the following operations, from an activation of the emergency descent, and relative to a reference horizontal distance ahead of the aircraft with respect to an initial position of the aircraft at the activation of the emergency descent: (b) calculating, with a correction value calculation device included in the target updating device, a correction value, taking into account variations of barometric pressure occurring during the emergency descent, the correction value being measured in the same units of measurement as the target security altitude and the correction value corresponding to a potential error between an actual current altitude of the aircraft and a measured barometric altitude which is based on a standard reference pressure and is thereby affected by a local QNH pressure of the current position; (c) arithmetically summing, with an updated target altitude calculation device included in the target updating device, the target security altitude and the correction value to obtain an updated target altitude that replaces the target altitude to be reached before the end of the emergency descent, the updated target altitude being corrected from potential collision risks caused by the potential error between the actual current altitude of the aircraft and the measured barometric altitude; and (d) transmitting the updated target altitude to an automatic control system of the aircraft to automatically conduct the emergency descent using the updated target altitude.