Engine-Out Go-Around Clearance Guidance Below Missed Approach Altitude

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Solution Overview

Problem

Pilots face challenges in executing engine out go-around maneuvers due to potential engine failure during go-around situations, especially when attempting to fly below the published missed approach altitude, which can lead to uncertainty in obstacle clearance and compliance with climb gradient requirements, particularly for older piston engine aircraft.

Innovation Solution

A system onboard an aircraft generates a pseudo engine out go-around procedure (PEOGAP) that maintains a minimum separation from obstacles by providing a minimum climb gradient and obstacle clearance, using a controller to generate a flight path based on aircraft performance and terrain data, displayed to the pilot.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If pilots fly below the published missed approach altitude during go-around, then operational flexibility is improved, but obstacle clearance safety deteriorates

Engineering Contradiction:
Improveoperational flexibilityVSAvoidobstacle clearance safety
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The system pre-calculates and stores engine-out climb performance data and obstacle clearance requirements before flight. During an actual engine-out go-around, the controller automatically retrieves this pre-computed information and generates the appropriate vertical path without requiring real-time pilot calculations, enabling safe operation below published altitude while maintaining obstacle clearance

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The controller acts as an intermediary between the pilot's go-around command and the aircraft's flight path. It automatically computes the optimal vertical trajectory that satisfies both the desired low-altitude operation and the mandatory obstacle clearance requirements, presenting a simplified command to the pilot while handling the complex safety calculations internally

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If older piston engine aircraft operate at maximum certificated weight, then payload capacity is improved, but climb gradient compliance deteriorates

Engineering Contradiction:
Improvepayload capacityVSAvoidclimb gradient compliance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system dynamically adjusts the minimum climb gradient requirement based on actual aircraft weight, temperature, and altitude conditions. Rather than using a fixed conservative gradient, the controller calculates the actual achievable climb performance in real-time and sets appropriate clearance requirements, enabling maximum weight operation while maintaining safety

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the climb gradient parameter from a fixed statutory value to a dynamic value that adapts to actual aircraft performance. The controller continuously monitors weight, temperature, and altitude parameters and adjusts the minimum climb gradient requirement accordingly, allowing older piston aircraft to operate at maximum weight while ensuring obstacle clearance

Inventive Principle:
Principle #35Parameter changes

3Reliability

If engine failure occurs during go-around, then immediate action is required, but pilot task saturation increases

Engineering Contradiction:
Improveimmediate response capabilityVSAvoidpilot task saturation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs self-service by automatically detecting engine failure, retrieving performance data, calculating the optimal vertical path, and presenting guidance to the pilot. This automation handles the complex computational tasks that would otherwise saturate the pilot, allowing the pilot to focus on executing the simplified flight path commands

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual mechanical process of pilot calculation and decision-making with an automated electronic controller. The controller substitutes for the pilot's cognitive processing by automatically computing climb gradients, obstacle clearances, and vertical paths, reducing the mental workload from complex calculations to simple flight path following

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3992947B1Engine out go around vertical clearance system and method
Publication Date: 2025.12.10 ROCKWELL COLLINS INC
  • EP3992947B1 patent drawingFigure 1
  • EP3992947B1 patent drawingFigure 2
  • EP3992947B1 patent drawingFigure 3

AI summary

A system and method onboard an aircraft generates pilot awareness of obstacle clearance during an engine out (EO) go around (GA) situation. The system herein receives inputs from either a pilot selection or aircraft state change indicating a GA below a published missed approach altitude and also receives an input from an engine status monitor indicating an EO situation. As a GA below the published missed approach altitude does not ensure obstacle clearance with an EO, the systems herein generate a pseudo engine out go around procedure (PEOGAP) which calculates a minimum climb gradient maintaining a minimum separation from all obstacles within an area bound by the published missed approach. Once generated, the systems herein display the PEOGAP to the pilot for adequate obstacle separation and pilot awareness.