Holding Pattern Entry Trajectory for Limited Airspace
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Solution Overview
Problem
Existing aircraft Flight Management Systems (FMS) often generate discontinuous and unflyable entry trajectory profiles for joining holding patterns due to limited airspace, leading to increased flight crew workload and confusion, especially in dense traffic or near terrain.
Innovation Solution
A method to build a modified entry trajectory profile by dividing airspace into sectors using an entry waypoint as a reference, determining a sector for approach, and generating a continuous and flyable trajectory profile based on the sector, allowing the aircraft to safely enter the holding pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the FMS builds an entry trajectory profile using conventional methods, then the trajectory can be generated quickly, but the trajectory becomes discontinuous and unflyable when airspace is limited
Solution Approach 1:
The airspace around the holding pattern is divided into multiple sectors using the entry waypoint as a reference point. The system determines which sector the aircraft is in and applies sector-specific trajectory building rules, allowing continuous trajectory generation even in limited airspace by adapting the entry method based on spatial segmentation.
Solution Approach 2:
The system dynamically adjusts the entry trajectory profile based on the determined sector and aircraft position. By making the trajectory building process adaptive to spatial conditions rather than using a fixed conventional method, the system ensures continuous and flyable trajectories are generated regardless of airspace limitations.
2Reliability
If the flight crew intervenes to modify the flight plan when trajectory discontinuity occurs, then the trajectory flyability can be improved, but the flight crew workload and confusion increase
Solution Approach 1:
The FMS automatically determines the aircraft's sector based on current position and trajectory, then autonomously builds the appropriate continuous entry trajectory profile without requiring flight crew intervention. This self-service capability eliminates the need for crew to manually modify flight plans, reducing workload and confusion while ensuring trajectory flyability.
3Reliability
If the FMS builds a continuous entry trajectory profile, then the trajectory becomes flyable, but the complexity of the trajectory building process increases
Solution Approach 1:
By dividing the airspace into sectors and determining which sector the aircraft is in, the system applies specific trajectory building rules for each sector. This segmentation approach manages complexity by breaking down the overall trajectory building process into manageable sector-specific segments rather than attempting to handle all cases with a single complex algorithm.
Solution Approach 2:
The system changes the trajectory building parameters based on the determined sector. By adjusting parameters such as entry angle, intercept point, and trajectory shape according to the sector classification, the system achieves continuous flyable trajectories while managing complexity through parameter adaptation rather than structural complexity.
Data Source
AI summary
A technique for building a modified entry trajectory profile for an aircraft to join a holding pattern at an entry waypoint despite the airspace available to build the entry trajectory being limited. In one aspect, instructions are received for an aircraft to join a holding pattern at an entry waypoint according to an entry trajectory profile. An airspace around the holding pattern is divided into sectors using the entry waypoint as a reference point. A discontinuity in the entry trajectory profile can be identified. In response to identifying the discontinuity in the entry trajectory profile, a modified entry trajectory profile can be built by i) determining the sector from which the aircraft would approach the entry waypoint with a current track angle of the aircraft moved to intersect the entry waypoint and with the aircraft pointing at the entry waypoint; and ii) generating the modified entry trajectory profile.