Rotorcraft Engine Transition Control for Automated Autorotation

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Solution Overview

Problem

Existing rotorcraft piloting methods during transitional phases, particularly in asymmetric flight conditions with engine failure, impose high workload on pilots, especially in low visibility conditions.

Innovation Solution

An assistance system and method that includes asymmetric regulation of engines, automatic identification of engine failure, and periodic generation of control orders based on multiple state parameters to automatically pilot the rotorcraft during autorotation, allowing the pilot to focus on other tasks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If asymmetric engine operation mode is used to reduce fuel consumption, then fuel efficiency is improved, but pilot workload increases during engine failure transition

Engineering Contradiction:
Improvefuel consumptionVSAvoidpilot workload
Core Design Contradiction:
Loss of energyVSEase of operation

Solution Approach 1:

The system pre-activates the standby engine before failure occurs, so that when engine failure happens, the replacement engine is already running and ready to provide power, eliminating the need for the pilot to manually start the engine during the critical transition phase

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control system automatically manages the engine transition process, detecting engine failure and controlling the standby engine activation and power redistribution without requiring pilot intervention, making the system self-managing during the critical transition

Inventive Principle:
Principle #25Self-service

2Measurement precision

If manual engine monitoring and control is used during transitional phase, then control precision is maintained, but pilot workload and stress increase significantly

Engineering Contradiction:
Improveengine state monitoringVSAvoidpilot workload
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system continuously monitors engine parameters and automatically adjusts control based on real-time feedback from sensors, maintaining precise control of the transition process without requiring the pilot to manually monitor multiple parameters under stress

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control system replaces manual pilot actions with automated electronic control systems that detect engine failure and manage the standby engine activation, substituting human mechanical control with automated sensor-based control

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

3Speed

If standby engine is kept in hot standby mode with all systems activated, then engine response time is improved, but energy consumption increases

Engineering Contradiction:
Improveengine activation speedVSAvoidstandby engine energy consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The standby engine operates in a dynamic intermediate state rather than static hot standby, maintaining rotational speed and essential systems activation levels that allow rapid response while consuming less energy than full hot standby operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the standby engine, controlling its rotational speed and system activation levels to optimize the balance between rapid activation capability and energy consumption during the standby phase

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4495009B1Method for assisting the piloting of a rotorcraft and rotorcraft thus equipped
Publication Date: 2025.08.27 EUROCOPTER FRANCE SA
  • EP4495009B1 patent drawingFigure 1~2

AI summary

The present invention relates to a method for assisting the piloting of a rotorcraft (1) comprising a first engine (2) and a second engine (3), each capable of transmitting, barring failure, engine torque to at least one rotor (4) providing at least one lift for the rotorcraft (1) in the air. The rotorcraft (1) comprises aerodynamic components (6) for piloting the rotorcraft (1). Such an assistance method comprises asymmetrical control of the first engine (2) and said second engine (3), identification of an engine failure of the first engine (2) using a failure monitor (7), and, in the event of an engine failure of the first engine (2), acceleration of the second engine (3) from standby mode to a synchronization mode in which the second engine (3) alone transmits engine power to said at least one rotor (4).