Rotorcraft LTE Alerts With Lateral Escape Guidance Display

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current rotorcraft displays do not timely convey information about potential or actual loss of tail rotor effectiveness (LTE) in a simple and intuitive manner, making it difficult for pilots to take corrective actions to avoid LTE conditions, especially during low airspeed operations.

Innovation Solution

A system and method that automatically detects LTE and displays an alert on a horizontal display indicating the LTE area's location relative to the rotorcraft, along with a direction to move to avoid it, optionally generating an exit flight plan to safely navigate away from the LTE zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If current rotorcraft displays present LTE information, then pilots can be aware of LTE conditions, but the information is not conveyed timely or in a simple to understand manner

Engineering Contradiction:
ImproveLTE information conveyanceVSAvoidPilot understanding and response
Core Design Contradiction:
Loss of informationVSEase of operation

Solution Approach 1:

The system uses color-coded symbology on the horizontal display to indicate LTE conditions and recovery actions. Different colors represent different LTE severity levels and guidance types, allowing pilots to quickly comprehend the situation without complex text or numerical data.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The system overlays LTE information on the existing horizontal display format, integrating it into the familiar HSI/PFD interface rather than requiring separate displays or complex instrument panels. This maintains the traditional display layout while adding critical LTE awareness capabilities.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Loss of information

If current rotorcraft displays provide LTE information, then pilots can understand the condition, but the response time is insufficient for safe recovery

Engineering Contradiction:
ImproveLTE warning informationVSAvoidPilot response time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system provides predictive LTE warnings that alert pilots to potential LTE conditions before they fully develop. By detecting early signs of vortex interference with the tail rotor, the system gives pilots advance notice and time to take corrective action before the situation becomes critical.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors flight parameters and provides real-time feedback to the pilot about LTE conditions and the effectiveness of recovery actions. This closed-loop feedback allows pilots to see the direct result of their control inputs and make timely adjustments.

Inventive Principle:
Principle #23Feedback

3Loss of information

If current rotorcraft displays show LTE information, then pilots receive some guidance, but the guidance is not sufficient to move away from LTE zone in sufficient time

Engineering Contradiction:
ImproveLTE location and guidance informationVSAvoidTime to exit LTE zone
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The system acts as an intermediary between the complex aerodynamic LTE phenomenon and the pilot by translating it into simple, intuitive graphical symbology on the horizontal display. The display shows the LTE zone location and provides step-by-step guidance cues that guide the pilot through the recovery process without requiring deep understanding of the underlying aerodynamics.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Loss of information

If the system provides detailed LTE information and guidance, then pilot situational awareness is enhanced, but cognitive workload increases

Engineering Contradiction:
ImproveLTE situational awarenessVSAvoidDisplay information complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The system segments LTE information into distinct, manageable components: LTE detection status, LTE zone location, and recovery guidance. Each component is presented separately on the display using unique symbology, allowing pilots to process information in discrete steps rather than overwhelming them with a single complex data stream.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4653817A1Method and system of automatic warnings and guidance for avoiding loss of tail rotor effectiveness on a rotorcraft
Publication Date: 2025.11.26 HONEYWELL INTERNATIONAL INC
  • EP4653817A1 patent drawingFigure 1
  • EP4653817A1 patent drawingFigure 2
  • EP4653817A1 patent drawingFigure 3

AI summary

A method for responding to loss of tail rotor effectiveness (LTE) on a rotorcraft having a tail rotor includes detecting an actual or predicted LTE, and determining a lateral LTE area relative to a position of the rotorcraft that is associated with the LTE. In response to the determination of the lateral LTE area, the method automatically displays an LTE alert on a horizontal display that indicates a location of the lateral LTE area relative to the position of the rotorcraft, and automatically indicates on the horizontal display a direction from the position of the rotorcraft that the rotorcraft should move to avoid the lateral LTE area.