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Electrically assisted steering with Electric Ground Taxi System (EGTS)

IP.com Disclosure Number: IPCOM000241556D
Publication Date: 2015-May-11
Document File: 4 page(s) / 135K

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The IP.com Prior Art Database

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Jim Mac Millan Fusaro: INVENTOR

Abstract

With increasing fuel cost, airlines use auxiliary power units on aircrafts to taxi aircrafts without the use of the main aircraft engines. During taxiing, the auxiliary power units are used for driving electric motors connected to the wheels of the main landing gear. The aircraft is steered by the pilot using a tiller which controls the wheels under the nose of the aircraft. The nose wheels are steered first followed by the wheels of the main landing gear. When the ground surface conditions are less than ideal, the nose wheels of the aircraft may have limited traction. This limited traction has an impact on the turning of the aircraft. The aircraft may deviate from the normal course on the taxiway as the limited traction of the nose wheels changes the angle of turn. This paper provides a method for steering the aircraft on ground by correlating the orientation of a tiller controlling the nose gear and the acceleration provided to the wheels of the main landing gear in less than ideal ground conditions.

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Page 01 of 4

Electrically assisted steering with Electric Ground Taxi System (EGTS)

Jim Mac Millan Fusaro

ABSTRACT

With increasing fuel cost, airlines use auxiliary power units on aircrafts to taxi aircrafts without the use of the main aircraft engines. During taxiing, the auxiliary power units are used for driving electric motors connected to the wheels of the main landing gear. The aircraft is steered by the pilot using a tiller which controls the wheels under the nose of the aircraft. The nose wheels are steered first followed by the wheels of the main landing gear. When the ground surface conditions are less than ideal, the nose wheels of the aircraft may have limited traction. This limited traction has an impact on the turning of the aircraft. The aircraft may deviate from the normal course on the taxiway as the limited traction of the nose wheels changes the angle of turn. This paper provides a method for steering the aircraft on ground by correlating the orientation of a tiller controlling the nose gear and the acceleration provided to the wheels of the main landing gear in less than ideal ground conditions


1. INTRODUCTION

The steering system in an aircraft comprises of steering of the main landing gear and steering of the nose gear. On ground, the steering of the aircraft is performed using the nose gear to turn the wheels present under the nose of the aircraft in the required direction. A dedicated tiller used by a pilot, controls the steering of the nose gear. The steering angle of the nose gear is based on the orientation and position of the tiller. The steering of the main landing gear is based on the steering of the nose gear. The wheels of the main landing gear are electrically controlled and the steering of the main landing gear is in proportion to the steering angle of the nose gear.

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Page 02 of 4

The turn of the aircraft is affected by various factors like steering angle of the nose wheel, weight of the airplane, location of the centre of gravity of the aircraft, the pavement surface conditions, the differential braking and the ground speed.

In normal pavement surface conditions, as the pilot steers the tiller to turn the aircraft, the steering angle of the nose gear increases and the nose wheels followed by the wheels of the main landing gear perform the required turn. However, when the ground surface conditions are less than ideal, like an icy taxiway or a wet taxiway, the nose wheels of the airplane may have limited traction. This limited traction has an impact on the turn of the aircraft. Although the pilot may steer the tiller to increase the steering angle of the nose gear, the actual turning angle of the aircraft may decrease due to limited traction of nose wheels on the ground. In extreme cases, the limited traction may lead to skidding of the wheels and the airplane may deviate from the taxiway or come in contact with an obstruction. Hence, there is a need for a steering control system which allows the aircraft to t...