Method for vehicle contingency planning

1. A method of aircraft operation, comprising:

determining a safety corridor based on a terrain and a noise threshold, the safety corridor comprising a three-dimensional corridor above the terrain;

flying an aircraft in a powered flight mode, comprising at a propulsion system of the aircraft, propelling the aircraft within the safety corridor;

while flying the aircraft in the powered flight mode, determining aircraft state data associated with the aircraft, the aircraft state data comprising an aircraft position;

while flying the aircraft in the powered flight mode, based on the aircraft state data, determining a contingency plan associated with an undesired aircraft condition, the undesired aircraft condition comprising failure of a propulsion system of the aircraft, wherein determining the contingency plan comprises:

selecting an emergency landing site; and

based on the emergency landing site, determining a set of control instructions associated with a set of flight control elements of the aircraft, wherein the set of flight control elements comprises at least one flight control surface and at least one actuator, wherein the contingency plan is updated continuously based on the aircraft state data while flying the aircraft, wherein the set of control instructions are associated with controlling the aircraft to fly toward the emergency landing site;

after determining the contingency plan, determining information indicative of the undesired aircraft condition;

based on the information, determining that the aircraft is undergoing the undesired aircraft condition; and

in response to determining that the aircraft is undergoing the undesired aircraft condition, autonomously controlling the aircraft to fly outside of the safety corridor based on the contingency plan and thereby changing the aircraft state data, comprising controlling the set of flight control elements according to the set of control instructions.

2. The method of claim 1 , wherein controlling the set of flight control elements according to the set of control instructions is performed in near-real time after determining that the aircraft is undergoing the undesired aircraft condition.

3. The method of claim 1 , wherein the aircraft is configured to contain a person.

4. The method of claim 1 , wherein:

the undesired aircraft condition comprises failure of a powerplant of the aircraft wherein the powerplant of the aircraft is configured to actuate a propulsion system;

the contingency plan is associated with a glidepath to an emergency landing site; and

autonomously controlling the aircraft based on the contingency plan comprises:

autonomously flying the aircraft substantially along the glidepath; and

autonomously landing the aircraft at the emergency landing site.

5. The method of claim 4 , wherein:

the aircraft comprises a temporary backup powerplant, wherein the temporary backup powerplant is configured to actuate the propulsion system;

autonomously flying the aircraft substantially along the glidepath is performed substantially without aircraft propulsion;

autonomously landing the aircraft at the emergency landing site is performed substantially without aircraft propulsion; and

autonomously controlling the aircraft based on the contingency plan further comprises, before autonomously flying the aircraft substantially along the glidepath, activating the temporary backup powerplant to substantially attain the glidepath.

6. The method of claim 5 , wherein:

the aircraft is a rotorcraft, and the propulsion system comprises a rotor;

the powerplant is a first motor configured to rotate the rotor; and

the temporary backup powerplant is a second motor configured to rotate the rotor.

7. The method of claim 6 , further comprising, at the rotorcraft, while the second motor is active, performing a turn at a bank angle to substantially attain the glidepath; wherein, while flying the aircraft substantially along the glidepath substantially without aircraft propulsion, an aircraft speed is less than a stall speed associated with the bank angle.

8. The method of claim 5 , wherein the aircraft further comprises a retrorocket, and activating the retrorocket to substantially attain the glide path in cooperation with the temporary backup powerplant.

9. The method of claim 1 , wherein:

the aircraft is a rotorcraft comprising:

a rotor;

a primary powerplant configured to rotate the rotor; and

a temporary backup powerplant configured to propel the rotorcraft, wherein the set of flight control elements comprises the temporary backup powerplant;

the undesired aircraft condition comprises failure of the primary powerplant;

determining that the aircraft is undergoing the undesired aircraft condition is performed at a first time;

at the first time, the rotorcraft is within an unsafe operation parameters region of a rotorcraft height-velocity curve, wherein the rotorcraft is not expected to be able to perform an unpowered landing at a descent rate less than a threshold descent rate;

controlling the set of flight control elements according to the set of control instructions comprises controlling the temporary backup powerplant to alter operation parameters of the rotorcraft; and

the method further comprises, after controlling the temporary backup powerplant to alter operation parameters of the rotorcraft, autonomously controlling the rotorcraft to perform the unpowered landing wherein the descent rate is less than the threshold descent rate.

10. The method of claim 9 , wherein the temporary backup powerplant comprises an electric motor configured to rotate the rotor.

11. The method of claim 9 , wherein controlling the temporary backup powerplant to alter operation parameters of the rotorcraft comprises increasing at least one of: a rotorcraft altitude and a rotorcraft ground speed.

12. The method of claim 1 , further comprising:

while propelling the aircraft within the safety corridor, receiving user guidance comprising a set of user-provided control inputs;

determining that the user guidance violates the safety corridor; and

in response, automatically controlling the aircraft to remain within the safety corridor.

13. A method of rotorcraft operation, comprising:

determining a safety corridor based on a terrain and a noise threshold, the safety corridor comprising a three-dimensional corridor above the terrain;

flying a rotorcraft in a powered flight mode, comprising, at a propulsion system of the aircraft, propelling the aircraft within the safety corridor, wherein the rotorcraft is propelled by a rotor;

while flying the rotorcraft in the powered flight mode, determining rotorcraft state data associated with the rotorcraft;

while flying the rotorcraft in the powered flight mode, based on the rotorcraft state data, determining a contingency plan associated with a propulsion failure condition, wherein determining the contingency plan comprises determining an emergency landing site and a plan to perform an unpowered landing at the emergency landing site, wherein the contingency plan is continuously updated while flying the rotorcraft;

determining information indicative of the propulsion failure condition;

based on the information, determining that the rotorcraft is undergoing the propulsion failure condition; and

in response to determining that the rotorcraft is undergoing the propulsion failure condition, autonomously controlling the rotorcraft based on the contingency plan, comprising:

modifying the safety corridor based on the plan to perform the unpowered landing at the emergency landing site;

autonomously operating the rotorcraft in autorotation within the modified safety corridor, wherein operating the rotorcraft comprises actuating at least one control surface using at least one actuator; and

autonomously performing the unpowered landing at the emergency landing site while the rotorcraft is in autorotation.

14. The method of claim 13 , wherein autonomously controlling the rotorcraft based on the contingency plan is performed in real time after determining that the aircraft is undergoing the propulsion failure condition.

15. The method of claim 13 , wherein the rotorcraft is configured to contain a person.

16. The method of claim 15 , wherein, throughout flying the rotorcraft in the powered flight mode, the rotorcraft does not receive control inputs from a pilot and does not contain a pilot.

17. The method of claim 13 , wherein:

the rotorcraft comprises a temporary backup powerplant configured to actuate the rotor of the rotorcraft, wherein the powered flight mode further comprises propelling the rotorcraft by the temporary backup powerplant;

determining that the rotorcraft is undergoing the propulsion failure condition is performed at a first time;

at the first time, the rotorcraft is outside an operation parameters region of a rotorcraft height-velocity curve, wherein the rotorcraft is calculated to be unable to perform an unpowered landing at a descent rate below a threshold descent rate; and

autonomously controlling the rotorcraft based on the contingency plan further comprises controlling the temporary backup powerplant to alter operation parameters of the rotorcraft at a second time, wherein the second time is subsequent to the first time and prior to a third time, wherein the rotorcraft is in the powered flight mode at the second time, wherein autonomously operating the rotorcraft in autorotation is performed at the third time.

18. The method of claim 17 , wherein controlling the temporary backup powerplant to alter operation parameters of the rotorcraft comprises increasing at least one of: a rotorcraft altitude and a rotorcraft ground speed.

19. The method of claim 17 , wherein:

the contingency plan is associated with a glidepath to the emergency landing site; and

autonomously controlling the rotorcraft based on the contingency plan further comprises autonomously flying the rotorcraft substantially along the glidepath while the rotorcraft is in autorotation.

20. The method of claim 19 , wherein the temporary backup powerplant comprises an electric motor configured to rotate the rotor of the rotorcraft.

21. The method of claim 13 , wherein the safety corridor comprises a boundary, limiting user operation of the rotorcraft.