초록 ▼

A process for monitoring the validity of a speed cue of an aircraft may include computing a coefficient of lift, which is representative of the lift of the aircraft, on the basis of values of static and total pressure. A first value of angle of incidence is computed on the basis of the computed coef

A process for monitoring the validity of a speed cue of an aircraft may include computing a coefficient of lift, which is representative of the lift of the aircraft, on the basis of values of static and total pressure. A first value of angle of incidence is computed on the basis of the computed coefficient of lift, and a second value of angle of incidence is determined. The difference between the first and second values of angle of incidence is computed, and the absolute value of the difference is compared with a predetermined threshold value. Based on the comparison, the speed cue is deemed valid if the absolute value of the difference is below the threshold value and deemed invalid otherwise.

대표청구항 ▼

The invention claimed is: 1. A process for monitoring the validity of at least one speed cue of an aircraft, which is determined on the basis of at least one value of static pressure and of at least one value of total pressure, wherein the following is carried out repetitively on a computer: consid

The invention claimed is: 1. A process for monitoring the validity of at least one speed cue of an aircraft, which is determined on the basis of at least one value of static pressure and of at least one value of total pressure, wherein the following is carried out repetitively on a computer: considering said values of static and total pressure, simultaneously used to determine said speed cue; calculating a coefficient of lift Cz which is representative of the lift of the aircraft on the basis of said values of static and total pressure; calculating a first value of angle of incidence from the values of static and total pressure via the calculated coefficient of lift; determining a second value of angle of incidence; computing the difference between said first and second values of angle of incidence; comparing the absolute value of this difference with a predetermined threshold value; and from said comparison one deduces that: said speed cue is valid, if the absolute value of said difference is below said threshold value; and said speed cue is not valid, otherwise, wherein: calculating said coefficient of lift Cz with the aid of the following expressions: in which: PS represents said static pressure value; PT represents said total pressure value; M represents the Mach number of the aircraft; S represents a reference area which depends on the geometry of the aircraft; nz represents the longitudinal load factor of the aircraft; m represents the mass of the aircraft; and g represents the acceleration due to gravity. 2. A device for monitoring the validity of at least one speed cue of an aircraft, which is determined on the basis of at least one value of static pressure and of at least one value of total pressure, which device comprises: a considering section that considers said values of static and total pressure, simultaneously used to determine said speed cue; a first computer that calculates, on the basis of said values of static and total pressure, a coefficient of lift Cz which is representative of the lift of the aircraft; a second computer that calculates a first value of angle of incidence from the values of static and total pressure via the calculated coefficient of lift Cz; a determining section that determines a second value of angle of incidence; a third computer that computes the difference between said first and second values of angle of incidence; a comparator that compares the absolute value of this difference with a predetermined threshold value; and a deducing section that deduces from said comparison that: said speed cue is valid, if the absolute value of said difference is below said threshold value; and said speed cue is not valid, otherwise, wherein: the first computer calculates said coefficient of lift Cz with the aid of the following expressions: in which: PS represents said static pressure value; PT represents said total pressure value; M represents the Mach number of the aircraft; S represents a reference area which depends on the geometry of the aircraft; nz represents the longitudinal load factor of the aircraft; m represents the mass of the aircraft; and g represents the acceleration due to gravity. 3. A process for monitoring the validity of at least one speed cue of an aircraft, which is determined on the basis of at least one value of static pressure and of at least one value of total pressure, wherein the following is carried out repetitively: considering said values of static and total pressure, simultaneously used to determine said speed cue; calculating a coefficient of lift Cz which is representative of the lift of the aircraft on the basis of said values of static and total pressure; calculating a first value of angle of incidence from the values of static and total pressure via the calculated coefficient of lift, and considering a relation between the coefficient Cz and the angle of incidence, centering of the aircraft and on the aircraft's Mach number; determining a second value of angle of incidence; computing the difference between said first and second values of angle of incidence; comparing the absolute value of this difference with a predetermined threshold value; and from said comparison one deduces that: said speed cue is valid, if the absolute value of said difference is below said threshold value; and said speed cue is not valid, otherwise, wherein: calculating said coefficient of lift Cz with the aid of the following expressions: in which: PS represents said static pressure value; PT represents said total pressure value; M represents the Mach number of the aircraft; S represents a reference area which depends on the geometry of the aircraft; nz represents the longitudinal load factor of the aircraft; m represents the mass of the aircraft; and g represents the acceleration due to gravity; obtaining curves which express the coefficient Cz as a function of the angle of incidence of the centering of the aircraft and the Mach number; and determining a corresponding set of curves for a specified configuration of the aircraft which are dependent on the centering of the angle of incidence and the Mach number. 4. The process as claimed in claim 1, wherein at least two values of static pressure are used, and wherein the average of these values of static pressure is considered. 5. The process as claimed in claim 1, wherein: a plurality of curves express the aircraft's coefficient of lift Cz as a function of the aircraft's angle of incidence such that each curve represents a different aircraft centering, which is the aircraft's center of gravity along a reference chord, and said first value of angle of incidence is calculated from the plurality of curves on the basis of said coefficient of lift Cz, the positions of the aircraft's slats and flaps, and the centering of said aircraft. 6. The process as claimed in claim 5, wherein said first value of angle of incidence is calculated moreover on the basis of the Mach number of the aircraft when the latter is in a smooth configuration. 7. The process as claimed in claim 1, wherein said second value of angle of incidence is determined with the aid of a measurement carried out by at least one angle of incidence probe. 8. The process as claimed in claim 1, for simultaneously monitoring the validity of a plurality of speed cues, wherein the process is implemented for each of said speed cues. 9. A system for generating at least one speed cue of an aircraft, said system comprising the monitoring device of claim 2 and further comprising: at least one first probe for measuring a value of static pressure; at least one second probe for measuring a value of total pressure; at least one fourth computer for computing said speed cue on the basis of said values of static and total pressure measured by said first and second probes; and at least one angle of incidence probe for measuring the angle of incidence of the aircraft, the measurement carried out by this angle of incidence probe being considered by said determining section of said monitoring device as second value of angle of incidence. 10. The system as claimed in claim 9, which moreover comprises a disabling section making it possible to disable the monitoring implemented by said monitoring device. 11. The system as claimed in claim 9, wherein said monitoring device forms part of a flight control computer which uses said speed cue, at least to compute flight control orders of the aircraft. 12. The system as claimed in claim 9, which comprises: a set of four first probes; a pressure sensor for measuring a value of static pressure; a set of three second probes; and three fifth computers for computing three different speed cues, on the basis of the value measured, respectively, by: two of said first probes and a first of said second probes; the other two first probes and a second of said second probes; and said pressure sensor and the third of said second probes, and wherein said monitoring device monitors the validity of each of said three speed cues. 13. The process of claim 1, wherein the angle of incidence is calculated by extrapolating a known angle of incidence for a known aircraft centering, which is the aircraft's center of gravity along a reference chord, based on the aircraft's actual centering. 14. The process of claim 1, wherein the process is performed by a flight control computer that relies on the speed cue for controlling the flight of the aircraft if the speed cue is determined to be valid and otherwise relies on another speed cue.