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Fixed Path Parabolic Spiraling Lateral Leg Transitions to Accommodate Increasing or Decreasing Groundspeed of an Airplane flying a Turn

IP.com Disclosure Number: IPCOM000247627D
Publication Date: 2016-Sep-21
Document File: 6 page(s) / 345K

Publishing Venue

The IP.com Prior Art Database

Related People

Jim Rumbo: AUTHOR [+5]

Abstract

Most commercial aircrafts today rely on Flight Management System (FMS) for lateral and vertical navigation. FMS flight plans for lateral navigation typically consist of straight segments with single or multi-curved transitions. These transitions are not physically flyable by the aircraft in certain flying conditions of acceleration or deceleration. This results in a lateral deviation of the aircraft from the displayed path causing uncertainty to the pilot. The proposed solution provides smooth lateral transitioning of an accelerating or decelerating aircraft from an inbound leg to an outbound leg of with a fixed Non-Standard Parabolic Spiral Lateral Transition path. As the acceleration or deceleration is incorporated into the spiraling path, aircraft will be able to confirm to the designated path with continuous adjustments to the roll angle without any cross track error.

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Fixed Path Parabolic Spiraling Lateral Leg Transitions to Accommodate Increasing or Decreasing Groundspeed of an Airplane flying a Turn

Jim Rumbo, James Haberstock, Mohan Chandrashekarappa, Sridevi Nagaraja, Kiran Venkataramana

ABSTRACT

Most commercial aircrafts today rely on Flight Management System (FMS) for lateral and vertical navigation. FMS flight plans for lateral navigation typically consist of straight segments with single or multi-curved transitions. These transitions are not physically flyable by the aircraft in certain flying conditions of acceleration or deceleration. This results in a lateral deviation of the aircraft from the displayed path causing uncertainty to the pilot. The proposed solution provides smooth lateral transitioning of an accelerating or decelerating aircraft from an inbound leg to an outbound leg of with a fixed Non- Standard Parabolic Spiral Lateral Transition path. As the acceleration or deceleration is incorporated into the spiraling path, aircraft will be able to confirm to the designated path with continuous adjustments to the roll angle without any cross track error.


1. Introduction

Modern commercial aircrafts are equipped with radio navigation systems which include a flight management computer that provides for both vertical and lateral navigation of the aircraft. In the lateral navigation mode, the computer functions to navigate and guide the aircraft along a flight plan made up of a series of waypoints connected by courses defining point to point legs of the flight plan. Flight crew makes flight plan entries and modifications through a Flight Management System (FMS) that builds a flight plan based on the inputs. The flight plan typically includes a plurality of legs that correspond to straight segments to be flown by the aircraft along with single curve or multi-curve

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transitions between the legs. In certain situations, the transition between two or more legs results in the FMS displaying a flight plan that is not physically flyable by the aircraft, particularly at increased speeds. When confronted with these unflyable transitions between legs, the aircraft travels a path that is different from the path displayed by the FMS. The lateral deviation of the aircraft from the underlying lateral path that is displayed is called the cross track error (XTK).

In the event of such a lateral deviation, the aircraft corrects itself by adjusting the roll angle bias and return to the flight plan. However, the amount of lateral deviation and time taken to return back to the lateral path are determined by the aircraft control capabilities. If the aircraft is already banked up to the maximum control roll limit, the XTK error will keep increasing and the airplane will deviate much further from the lateral path (See Figure 1).

Figure 1: Lateral Deviation or Cross Track Error (XTK) on a Curved Path Transition

If the aircraft is accelerating or decelerating over the transition, FMS systems lead...