Takeoff pitch guidance system and method
The present disclosure provides methods and system for providing takeoff pitch guidance for an aircraft. Takeoff pitch guidance for the aircraft is provided in a pitch target mode at a time of takeoff. The pitch target mode corresponds to determining pitch as a function of a target pitch based on aircraft operating parameters. A transition event is detected while in the pitch target mode. The takeoff pitch guidance for the aircraft is transitioned from the pitch target mode to an airspeed error mode after the transition event is detected and the takeoff pitch guidance is provided in the airspeed error mode. The airspeed error mode corresponds to determining pitch based on a difference between an actual speed and a target speed of the aircraft.
1. A method for providing takeoff pitch guidance for an aircraft, the method comprising:
providing takeoff pitch guidance for the aircraft in a pitch target mode at a time of takeoff, the pitch target mode corresponding to determining a target pitch as a function of aircraft operating parameters;
detecting a transition event while in the pitch target mode, wherein the transition event corresponds to when a weight-off-wheels condition of the aircraft is met,
transitioning the takeoff pitch guidance for the aircraft from the pitch target mode to an airspeed error mode after the transition event is detected and after a time delay that starts when the weight-off-wheels condition is met, the airspeed error mode corresponding to determining the target pitch based on a difference between an actual speed and a target speed of the aircraft; and
providing the takeoff pitch guidance in the airspeed error mode,
wherein the method further comprises providing a minimum pitch limit and a maximum pitch limit when in the airspeed error mode.
2. The method of claim 1 , further comprising determining the time delay based on the aircraft operating parameters.
3. The method of claim 1 , wherein determining the target pitch comprises setting the target pitch to an initial target pitch, monitoring a current pitch of the aircraft, and changing the initial target pitch as a function of the current pitch of the aircraft to reach a final target pitch.
4. The method of claim 3 , wherein changing the initial target pitch comprises setting the target pitch to an intermediate target pitch, and changing the intermediate target pitch to the final target pitch.
5. The method of claim 4 , wherein the intermediate target pitch is set as a function of a first rate of change of pitch over time, and the final target pitch is set as a function of a second rate of change of pitch over time.
6. The method of claim 4 , wherein the intermediate target pitch corresponds to a value where a tail of the aircraft has cleared a ground striking point.
7. The method of any one of claim 4 , wherein changing the intermediate target pitch comprises setting the target pitch to the final target pitch when the transition event occurs.
8. The method of claim 1 , wherein the airspeed error mode comprises determining the target pitch of the aircraft based on a takeoff airspeed control law.
9. The method of claim 1 , wherein providing pitch guidance comprises displaying a pitch target marker on an aircraft display when in the pitch target mode and displaying a flight director on the aircraft display when in the airspeed error mode.
10. A system for providing takeoff pitch guidance for an aircraft, the system comprising:
a processing unit; and
a non-transitory computer-readable memory having stored thereon program instructions executable by the processing unit for:
providing takeoff pitch guidance for the aircraft in a pitch target mode at a time of takeoff, the pitch target mode corresponding to determining a target pitch as a function of aircraft operating parameters;
detecting a transition event while in the pitch target mode, wherein the transition event corresponds to when a weight-off-wheels condition of the aircraft is met,
transitioning the takeoff pitch guidance for the aircraft from the pitch target mode to an airspeed error mode after the transition event is detected and after a time delay that starts when the weight-off-wheels condition is met, the airspeed error mode corresponding to determining the target pitch based on a difference between an actual speed and a target speed of the aircraft; and
providing the takeoff pitch guidance in the airspeed error mode,
wherein the program instructions are further executable by the processing unit for providing a minimum pitch limit and a maximum pitch limit when in the airspeed error mode.
11. The system of claim 10 , wherein the program instructions are further executable by the processing unit for determining the time delay based on the aircraft operating parameters.
12. The system of claim 10 , wherein determining the target pitch comprises setting the target pitch to an initial target pitch, monitoring a current pitch of the aircraft, and changing the initial target pitch as a function of the current pitch of the aircraft to reach a final target pitch.
13. The system of claim 12 , wherein changing the initial target pitch comprises setting the target pitch to an intermediate target pitch, and changing the intermediate target pitch to the final target pitch.
14. The system of claim 13 , wherein the intermediate target pitch is set as a function of a first rate of change of pitch over time, and the final target pitch is set as a function of a second rate of change of pitch overtime.
15. The system of claim 13 , wherein the intermediate target pitch corresponds to a value where a tail of the aircraft has cleared a ground striking point.
16. The system of claim 13 , wherein changing the intermediate target pitch comprises setting the target pitch to the final target pitch when the transition event occurs.
17. The system of claim 10 , wherein the airspeed error mode comprises determining the target pitch of the aircraft based on a takeoff airspeed control law.
18. The system of claim 10 , wherein providing pitch guidance comprises displaying a pitch target marker on an aircraft display when in the pitch target mode and displaying a flight director on the aircraft display when in the airspeed error mode.