Shortened aircraft holding patterns

• US 20040122567A1
• Filed: 12/20/2002
• Published: 06/24/2004
• Est. Priority Date: 12/20/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Gaier, Chad E.
• Granted Patent: US 6,847,866 B2
• Time in Patent Office: Days
• US Class Current: 701/4
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
• CPC Class Codes: G05D 1/0202 specially adapted to aircraft
• CPC Class Codes: G08G 5/0039 Modification of a flight plan
• CPC Class Codes: G08G 5/025 Navigation or guidance aids radar or analogous systems specially adapted for landing purposes G01S13/913

Abstract

Methods, apparatus and program product are provided to obtain a shortened holding pattern exit path for an aircraft from its current position (CP) in or entering a holding pattern to an allowed exit point (EP) of the holding pattern. The flight management system (FMS) determines which segment of the holding pattern the aircraft is currently on, i.e., A, B, or C defined in terms of the holding pattern turn points (TP1, TP2, TP3, TP4) and the waypoint (SP) which is symmetrical to the desired EP. The FMS compares the aircraft CP with EP and SP locations and directs turns at the appropriate waypoints to give the shortest allowed exit pathway. Both Type I and Type II holding pattern entries are accommodated.

Claims

1. A method for providing an allowed shortened holding pattern exit path for an aircraft from its current position (CP) in a holding pattern to an allowed exit point (EP) from the holding pattern wherein the holding pattern comprises inbound and outbound legs, a near turn leading from a first turning point (TP1) at an inward end of the inbound leg to a second turning point (TP2) at an inward end of the outbound leg and a far turn leading from a third turning point (TP3) at an outward end of the outbound leg to a fourth turning point (TP4) at an outward end of the inbound leg and where the (EP) lies on the inbound leg and a symmetrical point (SP) lies opposite and symmetrical to the EP on the outbound leg, the method comprising:

(a) determining the holding pattern segment A, B, or C on which the aircraft is currently located, that is, on segment A between (TP3) and the (EP) or on segment B between the (EP) and the (SP) or on C between the (SP) and (TP3); and

(a.1) if on segment A, directing the aircraft along the holding pattern to reach the (EP);

or

(a.2) if on segment B directing the aircraft along the holding pattern to the (SP) and at the (SP) directing a turn toward the inbound leg to substantially directly reach the (EP);

or

(a.3) if on segment C, determining the shortest distance D along the holding pattern from the (SP) to the (CP), directing a turn to the inbound leg and continuing along the inbound leg for reciprocal distance−

D to reach the (EP); and

(b) at the (EP) directing a turn to the desired departure path.

2. The method of claim 1 further comprising prior to step (a.1), the step of determining whether an “

Exit Hold”

has occurred, and if NO (FALSE), repeating this step until YES (TRUE) occurs, then proceeding.

3. The method of claim 1 wherein D includes a flight control lag distance.

4. The method of claim 1 wherein segment B includes a linear extension of the outbound leg, extending in an inbound direction from (TP2).

5. The method of claim 1 further comprising prior to step (a), the steps of:

(1) determining whether the aircraft is on an entry path into the holding pattern or already in the holding pattern, and;

(2) if on an entry path into the holding pattern, then first executing steps (2.1) -(2.3), otherwise skipping steps (2.1)-(2.3);

(2.1) determining a first tangent point where the path of the entering aircraft tangentially intersects a first circle, the first circle being tangent to the outbound leg at a second tangent point;

(2.2) at the first tangent point, directing a turn onto the first circle toward the outbound leg of the holding pattern;

(2.3) at the second tangent point, directing a roll-out onto the outbound leg of the holding pattern thereby arriving in the holding pattern; and

(2.4) proceeding to step (a).

6. The method of claim 5 further comprising prior to step (2.1), determining whether the entry path is a Type I or a Type II entry path and if a Type I entry path executing steps (2.1)-(2.3) wherein the fist and second tangent points are for the Type I entry and the second tangent point may lie on an extension of the outbound leg, such location being considered within segment B for determining a shortened holding pattern exit path, or if a Type II entry path, executing steps (2.1)-(2.3) wherein the first and second tangent points are for the Type II entry, and the second tangent point is considered as being within segment B for purposes of determining a shortened holding pattern exit path, and then proceeding to step (2.4).

7. An apparatus for directing an aircraft on an allowed shortened holding pattern exit path from its current position (CP) in a holding pattern to an allowed exit point (EP) from the holding pattern wherein the holding pattern comprises inbound and outbound legs, a near turn leading from a first turning point (TP 1) at an inward end of the inbound leg to a second turning point (TP2) at an inward end of the outbound leg and a far turn leading from a third turning point (TP3) at an outward end of the outbound leg to a fourth turning point (TP4) at an outward end of the inbound leg and where the (EP) lies on the inbound leg and a symmetrical point (SP) lies opposite and symmetrical to the (EP) on the outbound leg, comprising:

(1) a processor;

(2) memory coupled to the processor;

(3) a display unit coupled to the process for indicating suggested course changes or an autopilot coupled to the processor for actuating aircraft control surfaces to produce course changes or both;

(4) a program residing in memory and being executed by the processor for directing course changes on the display or to the autopilot or both, the program comprising;

(4.a) determining the holding pattern segment A, B, or C on which the aircraft is currently located, that is, on segment A between (TP3) and the (EP) or on segment B between the (EP) and the (SP) or on C between the (SP) and (TP3); and

(4.a.1) if on segment A, directing the aircraft along the holding pattern to reach the (EP);

or

(4.a.2) if on segment B directing the aircraft along the holding pattern to the (SP) and at the (SP) directing a turn toward the inbound leg to substantially directly reach the (EP);

or

(4.a.3) if on segment C, determining the shortest distance D along the holding pattern from the (SP) to the (CP), directing a turn to the inbound leg and continuing along the inbound leg for reciprocal distance−

D to reach the (EP); and

(4.b) at the (EP) directing a turn to the desired departure path.

8. The apparatus of claim 7 wherein the program residing in memory further comprises prior to step (4.a.1), the step of determining whether an “

Exit Hold”

has occurred, and if NO (FALSE), repeating this step until YES (TRUE) occurs, then proceeding.

9. The apparatus of claim 7 wherein D includes a flight control lag distance determined by the processor using aircraft performance data stored in the memory.

10. The apparatus of claim 7 wherein segment B includes a linear extension of the outbound leg, extending in an inbound direction from (TP2).

11. The apparatus of claim 7 wherein the program residing in memory further comprising prior to step (4.a), the steps of:

(i) determining whether the aircraft is on an entry path into the holding pattern or already in the holding pattern, and;

(ii) if on an entry path into the holding pattern, then first executing steps (ii.1) -(ii.3), otherwise skipping steps (ii.1)-(ii.3);

(ii.1) determining a first tangent point where the path of the entering aircraft tangentially intersects a first circle, the first circle being tangent to the outbound leg at a second tangent point;

(ii.2) at the first tangent point, directing a turn onto the first circle toward the outbound leg of the holding pattern;

(ii.3) at the second tangent point, directing a roll-out onto the outbound leg of the holding pattern thereby arriving in the holding pattern; and

(iii) proceeding to step (4.a).

12. The apparatus of claim 11 wherein the program residing in memory further comprises prior to step (ii.1) determining whether the entry path is a Type I or a Type II entry path and if a Type I entry path executing steps (ii.1)-(ii.3) wherein the fist and second tangent points are for the Type I entry and the second tangent point may lie on an inward extension of the outbound leg, such location being considered within segment B for determining a shortened holding pattern exit path, or if a Type II entry path, executing steps (ii.1)-(ii.3) wherein the first and second tangent points are for the Type II entry, and the second tangent point is considered as being within segment B for purposes of determining a shortened holding pattern exit path, and then proceeding to step (iii).

13. A program product comprising:

(1) a program for providing an allowed shortened holding pattern exit path for an aircraft from its current position (CP) in a holding pattern to an allowed exit point (EP) from the holding pattern wherein the holding pattern comprises inbound and outbound legs, a near turn leading from a first turning point (TP1) at an inward end of the inbound leg to a second turning point (TP2) at an inward end of the outbound leg and a far turn leading from a third turning point (TP3) at an outward end of the outbound leg to a fourth turning point (TP4) at an outward end of the inbound leg and where the (EP) lies on the inbound leg and a symmetrical point (SP) lies opposite and symmetrical to the EP on the outbound leg, the method comprising;

(1.a) determining the holding pattern segment A, B, or C on which the aircraft is currently located, that is, on segment A between (TP3) and the (EP) or on segment B between the (EP) and the (SP) or on C between the (SP) and (TP3); and

(1.a.1) if on segment A, directing the aircraft along the holding pattern to reach the (EP);

or

(1.a.2) if on segment B directing the aircraft along the holding pattern to the (SP) and at the (SP) directing a turn toward the inbound leg to substantially directly reach the (EP);

or

(1.a.3) if on segment C, determining the shortest distance D along the holding pattern from the (SP) to the (CP), directing a turn to the inbound leg and continuing along the inbound leg for reciprocal distance−

D to reach the (EP); and

(1.b) at the (EP) directing a turn to the desired departure path; and

(2) signal bearing media bearing said program.

14. The program product of claim 13 further comprising prior to step (1.a.1), the step of determining whether an “

Exit Hold”

has occurred, and if NO (FALSE), repeating this step until YES (TRUE) occurs, then proceeding.

15. The program product of claim 13 wherein D includes a flight control lag distance.

16. The program product of claim 13 wherein segment B includes a linear extension of the outbound leg, extending in an inbound direction from (TP2).

17. The program product of claim 13 further comprising prior to program step (1.a), the steps of:

(1) determining whether the aircraft is on an entry path into the holding pattern or already in the holding pattern, and;

(2) if on an entry path into the holding pattern, then first executing steps (2.1) -(2.3), otherwise skipping steps (2.1)-(2.3);

(2.1) determining a first tangent point where the path of the entering aircraft tangentially intersects a first circle, the first circle being tangent to the outbound leg at a second tangent point;

(2.2) at the first tangent point, directing a turn onto the first circle toward the outbound leg of the holding pattern;

(2.3) at the second tangent point, directing a roll-out onto the outbound leg of the holding pattern thereby arriving in the holding pattern; and

(2.4) proceeding to step (1.a).

18. The program product of claim 17 wherein the program further comprises prior to step (2.1) determining whether the entry path is a Type I or a Type II entry path and if a Type I entry path executing steps (2.1)-(2.3) wherein the fist and second tangent points are for the Type I entry and the second tangent point may lie on an extension of the outbound leg, such location being considered within segment B for determining a shortened holding pattern exit path, or if a Type II entry path, executing steps (2.1)-(2.3) wherein the first and second tangent points are for the Type II entry, and the second tangent point is considered as being within segment B for purposes of determining a shortened holding pattern exit path, and then proceeding to step (1.a).