Aeronautical holding pattern calculation for solving high wind and protected airspace issues

An apparatus comprising:

• a memory;
• and
• a processor coupled to the memory and configured to provide guidance for an aircraft by implementing the following steps:
• receiving holding instructions for the aircraft, wherein the holding instructions comprise a holding fix, a holding direction, and an inbound leg course;
• obtaining an airspeed for the aircraft;
• obtaining a wind speed and a wind direction affecting the aircraft;
• calculating a holding pattern for the aircraft using the holding instructions, the wind speed, the wind direction, an inbound leg duration, and the airspeed;
• obtaining Federal Aviation Administration (FAA) holding pattern protected airspace template limits associated with the holding fix;
• and
• presenting the holding pattern and the FAA holding pattern protected airspace template limits to a flight crew member on the aircraft,
• wherein the holding pattern comprises an inbound leg, an outbound turn, an outbound leg, and an inbound turn, and wherein the processor, in being configured to calculate the holding pattern for the aircraft, is configured to:
• calculate an inbound leg starting point using the inbound leg course, the inbound leg duration, and the airspeed;
• calculate a curved path trajectory for the aircraft using the airspeed, the wind speed, the wind direction, and a rate-of-turn for the aircraft, wherein the curved path trajectory is a path the aircraft will fly when the aircraft turns at the rate-of-turn and at the airspeed when the aircraft is subjected to the wind speed and the wind direction, and wherein the curved path trajectory comprises an outbound turn portion and an inbound turn portion;
• orient at least part of the outbound turn portion on the holding fix at the holding fix such that the inbound leg course is tangent to the outbound turn portion at the holding fix;
• orient at least part of the inbound turn portion on the inbound leg starting point such that the inbound leg course is tangent to the inbound turn portion at the holding fix;
• and
• determine the outbound leg for the holding pattern, wherein the outbound leg is a line that is tangent to both the outbound turn portion and the inbound turn portion and is not coincident with the inbound leg.

A computer program product comprising computer executable instructions stored on a non-transitory computer readable medium that when executed by a processor causes a flight management system (FMS) to perform the following:

• receive holding instructions for an aircraft, wherein the holding instructions comprise a holding fix, a holding direction, and an inbound leg course;
• obtain an airspeed for the aircraft;
• obtain a wind speed and a wind direction;
• calculate a holding pattern for the aircraft using the holding instructions, the wind speed, the wind direction, an inbound leg duration, and the airspeed;
• obtain protected airspace limits associated with the holding fix;
• determine whether the holding pattern is within the protected airspace limits;
• and
• notify a flight crew member to take corrective action based upon at least part of the holding pattern not being within the protected airspace limits,
• wherein the holding pattern comprises an inbound leg, an outbound turn, an outbound leg, and an inbound turn, and wherein the computer executable instructions, when executed by the processor, further cause the FMS to:
• calculate an inbound leg starting point using the inbound leg course, the inbound leg duration, and the airspeed;
• calculate a curved path trajectory for the aircraft using the airspeed, the wind speed, the wind direction, and a rate-of-turn for the aircraft, wherein the curved path trajectory is a path the aircraft will fly when the aircraft turns at the rate-of-turn and at the airspeed when the aircraft is subjected to the wind speed and the wind direction, and wherein the curved path trajectory comprises an outbound turn portion and an inbound turn portion;
• calculate the outbound turn portion of the curved path trajectory for the aircraft using the airspeed for the aircraft, the wind speed, the wind direction, and the rate-of-turn for the aircraft, wherein the curved path trajectory is the path the aircraft will fly when the aircraft turns at the rate-of-turn and at the airspeed when the aircraft is subjected to the wind speed and the wind direction, and wherein the outbound turn portion intersects the holding fix such that the inbound leg course is tangent to the outbound turn portion at the holding fix;
• calculate the inbound turn portion of the curved path trajectory for the aircraft using the airspeed for the aircraft, the wind speed, the wind direction, and the rate-of-turn for the aircraft, wherein the inbound turn portion does not intersect the outbound turn portion, and wherein the inbound turn portion intersects the inbound leg starting point such that the inbound leg course is tangent to the inbound turn portion at the inbound leg starting point;
• and
• determine the outbound leg for the holding pattern, wherein the outbound leg is a line that is tangent to both the outbound turn portion and the inbound turn portion and is not the same as the inbound leg.

An aircraft, comprising:

• an airframe;
• at least one engine attached to the airframe;
• an avionics system attached to the airframe;
• and
• a flight management system (FMS) attached to the airframe and in communication with the avionics system, wherein the FMS:
• receives holding instructions for the aircraft, wherein the holding instructions comprise a holding fix, a holding direction, and an inbound leg course;
• obtains an airspeed for the aircraft from the avionics system;
• obtains a wind speed and a wind direction affecting the aircraft;
• calculates a holding pattern for the aircraft using the holding instructions, the wind speed, the wind direction, an inbound leg duration, and the airspeed;
• obtains Federal Aviation Administration (FAA) protected airspace lateral limits associated with the holding fix;
• determines that the holding pattern is not within the FAA holding pattern protected airspace template limits;
• calculates a different airspeed for the aircraft that will keep the holding pattern within the FAA holding pattern protected airspace template limits;
• indicates the different airspeed required for the aircraft to remain in the FAA holding pattern protected airspace template limits;
• and
• graphically displays the holding pattern and the FAA protected airspace lateral limits to a flight crew member on the aircraft through either the FMS or the avionics system, wherein the holding pattern legs are not coincident with the FAA protected airspace lateral limits.