Display system for an aircraft

1. A display system for an aircraft, comprising:

a central unit configured to determine a speed vector of the aircraft and to determine a longitudinal margin of maneuver of the aircraft, wherein the longitudinal margin of maneuver is expressed as a load factor and is related to one of a pitch-up maneuver and a pitch-down maneuver; and

a display unit connected to the central unit and including a display screen configured to display a first characteristic sign illustrating the speed vector and a second characteristic sign illustrating the longitudinal margin of maneuver, wherein a distance between the first characteristic sign and the second characteristic sign is proportional to the longitudinal margin of maneuver.

2. The display system of claim 1 , wherein the display screen is a heads-up display screen.

3. The display system of claim 1 , wherein the first characteristic sign is shaped as a diamond and the second characteristic sign is shaped as a chevron.

4. The display system of claim 1 , wherein the central unit includes:

a first determining unit configured to determine a longitudinal margin of maneuver related to a pitch-up maneuver; and

a second determining unit configured to determine a longitudinal margin of maneuver related to a pitch-down maneuver.

5. The display system of claim 4 , wherein the first determining unit determines the longitudinal margin by selecting the smaller of a first load factor margin and an angle of incidence margin.

6. The display system of claim 5 , wherein the angle of incidence margin is calculated from the following expression:

Δα=1−[( Nz/ΔN max)*((αmax−α)/(α−α0))],

wherein Δα is the angle of incidence margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, α is a angle of incidence, a max is a maximum angle of incidence, and α0 is a zero lift angle of incidence.

7. The display system of claim 4 , wherein the second determining unit determines the longitudinal margin by selecting the smaller of a first load factor margin and a speed margin.

8. The display system of claim 7 , wherein the speed margin is calculated from the following expression:

ΔV= 1−[( Nz+Kp ( V max− V )− Kd ( dV/dt ))/Δ N max],

wherein ΔV is the speed margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, V is a speed of the aircraft, Vmax is a maximum speed of the aircraft, (dV/dt) is a derivative with respect to time of the speed V, and Kp and Kd are predetermined parameters.

9. The display system of claim 1 , wherein the display unit displays the second characteristic sign only when the determined longitudinal margin of maneuver is less than a predetermined value.

10. A display system for an aircraft, comprising:

a central unit including a first determining unit configured to determine a speed vector of the aircraft and a second determining unit configured to determine a longitudinal margin of maneuver of the aircraft; and

a display unit including a display screen configured to display a first characteristic sign illustrating the speed vector of the aircraft and a second characteristic sign illustrating the longitudinal margin of maneuver of the aircraft, wherein a distance between the first characteristic sign and the second characteristic sign is proportional to the longitudinal margin of maneuver.

11. The display system of claim 10 , wherein the second determining unit includes a first selecting unit configured to determine a longitudinal margin of maneuver related to a pitch-up maneuver by selecting the smaller of a pitch-up load factor margin and an angle of incidence margin.

12. The display system of claim 11 , wherein the second determining unit includes a second selecting unit configured to determine a longitudinal margin of maneuver related to a pitch-down maneuver by selecting the smaller of a pitch-down load factor margin and a speed margin.

13. The display system of claim 12 , wherein the second determining unit includes:

a first margin calculating unit configured to determine the pitch-up load factor margin;

a second margin calculating unit configured to determine the angle of incidence margin;

a third margin calculating unit configured to determine the pitch-down load factor margin; and

a fourth margin calculating unit configured to determine the speed margin.

14. The display system of claim 13 , wherein the second margin calculating unit determines the angle of incidence margin using the following expression:

Δα=1−[( Nz/ΔN max)*((αmax−α)/(α−α0))],

wherein Δα is the angle of incidence margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, α is a angle of incidence, αmax is a maximum angle of incidence, and α0 is a zero lift angle of incidence.

15. The display system of claim 13 , wherein the fourth margin calculating unit determines the speed margin using the following expression:

ΔV= 1−[( Nz+Kp ( V max− V )− Kd ( dV/dt ))/Δ N max],

wherein ΔV is the speed margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, V is the speed of the aircraft, Vmax is a maximum speed of the aircraft, (dV/dt) is a derivative with respect to time of the speed V, and Kp and Kd are predetermined parameters.

16. A display system for an aircraft, comprising:

a central unit configured to determine a speed vector of the aircraft and to determine a longitudinal margin of maneuver of the aircraft; and

a display unit connected to the central unit and including a display screen configured to display a first characteristic sign illustrating the speed vector and a second characteristic sign illustrating the longitudinal margin of maneuver, wherein a distance between the first characteristic sign and the second characteristic sign is proportional to the longitudinal margin of maneuver.

17. The display system of claim 16 , wherein:

the longitudinal margin of maneuver is expressed as a load factor and is related to one of a pitch-up maneuver and a pitch-down maneuver;

the display screen is a heads-up display screen;

the first characteristic sign is shaped as a diamond; and

the second characteristic sign is shaped as a chevron.

18. The display system of claim 16 , wherein the central unit includes:

a first determining unit configured to determine a longitudinal margin of maneuver related to a pitch-up maneuver; and

a second determining unit configured to determine a longitudinal margin of maneuver related to a pitch-down maneuver, wherein:

the first determining unit determines the longitudinal margin by selecting the smaller of a first load factor margin and an angle of incidence margin; and

the second determining unit determines the longitudinal margin by selecting the smaller of a first load factor margin and a speed margin.

19. The display system of claim 18 , wherein:

the angle of incidence margin is calculated from the following expression:

Δα=1−[( Nz/ΔN max)*((αmax−α)/(α−α0))],

wherein Δα is the angle of incidence margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, α is a angle of incidence, αmax is a maximum angle of incidence, and α0 is a zero lift angle of incidence; and

the speed margin is calculated from the following expression:

ΔV= 1−[( Nz+Kp ( V max− V )− Kd ( dV/dt ))/Δ N max],

wherein ΔV is the speed margin, Nz is a load factor, ΔNmax is a maximum value of margin of maneuver depicted, V is a speed of the aircraft, Vmax is a maximum speed of the aircraft, (dV/dt) is a derivative with respect to time of the speed V, and Kp and Kd are predetermined parameters.

20. The display system of claim 16 , wherein the display unit displays the second characteristic sign only when the determined longitudinal margin of maneuver is less than a predetermined value.