Epsilon Optics Aerospace Ltd

Epsilon Optics Aerospace Ltd is focused on providing bespoke solutions for the long term monitoring of aerospace and other critical defence related structures.

Airbus A320

It is continuing the work originally started by Insensys Ltd. Sensor systems have been provided for both fixed and rotary wing aircraft and for naval applications. These have included monitoring structures such as aircraft wing spars and landing gears for both manned and unmanned fixed wing aircraft. For helicopters work has focused on measuring loads in critical rotor head components and rotor blades. On naval platforms hull structures are being monitored. The data from the systems is being used to support the introduction of “on condition maintenance”. It includes determining actual life usage and the detection of hazardous events such as impacts and, in the case of landing gears, heavy landings.

The system comprises three main elements:

  1. Sensor: These contain the fibre optic strain measuring device including temperature compensation. Each is designed to meet the specific application with the FBG tuned to measure the required range of strains. They may take a number of forms including embedded and surface bonded sensors. For certain applications, particularly complex metallic structures such as landing gears, sensor carriers may be used that are mechanically attached to the structure in such a manner that they sense the loads being applied. Aerospace qualified materials are used wherever possible and a number of sensors have been successfully tested to DO-160E.
  2. Sensor interrogator: The EOAL interrogator uses Time Domain Multiplexing (TDM) to provide a light weight, compact unit that requires low electrical power. Further Information. The rate at which it interrogates the FBG sensors is adjustable up to a maximum speed of 10kHz; it has been successfully used to detect impacts to composite structures. As it is fully solid state it is robust and has undergone a full test programme to demonstrate that it meets the requirements of DO-160E. This robustness was demonstrated during tests where it was mounted on a helicopter rotor head. The data output is digital (currently RS422 but alternative Ethernet outputs are possible) and can be fed directly into the aircraft’s data bus for transmission to the maintenance management system. Alternatively self contained data storage is possible for post flight download. The unit can also be battery powered to provide a completely self contained system.
  3. ConnectorInterconnecting optical fibres and connectors: The interrogator is normally mounted remote from the sensors, either within an avionics bay or other suitable location. The two are linked via a single mode optical fibre. Optical connectors are required to facilitate removal of the component being monitored for maintenance etc or to ease installation for instance where the fibre is routed through a major fuselage break point. EOAL is working closely with a number of specialist optical fibre and connector manufacturers to provide robust solutions to meet these requirements.

EOAL has and is working with a number of major Tier 1 aerospace companies in both Europe and the USA, and is familiar with the requirements of ITAR. Its success is built on a willingness to tailor the solution to meet the customer’s specific requirement.

Published Papers

Royal Aeronautical Society: The Future Rotorcraft: Enabling Capability through the Application of Technology, 15-16 June 2011
Use of Fibre Optic Sensors to Measure In-Service Loads in Critical Rotor Components.
R. Caesley
Epsilon Optics Ltd

American Helicopter Society 66th Annual Forum, May 11-13 2010
Advanced CBM Technologies for Helicopter Rotor Systems – Full Scale Rotor Demonstration and Test Results
J. R. Andrews, M. J. Augustin
Bell Helicopters Textron Inc

Development of Optical Fibre Strain Measurement for Monitoring Composite Structures.
D. Roberts and R. Caesley
Moog Insensys Ltd

Structural loads monitoring of an Unmanned Air Vehicle
M. Frovel, G. Carrion, J.M. Pintado
INTA. Area de Materiales Compuestos, Torrejon de Ardoz, Espana.

The Embedding of Optical Fibre Sensors for SHM
M. Volanthen, L. Rumsey, R. Caesley, A. Ghoshal, G. Welsh and N. Bordick
Insensys Ltd, United Technologies Research Centre and Aviation Applied Technology Directorate, US Army.

Design and implementaion of complete fibre-optic sensing solutions



Fiber-optic sensing for smarter, stronger, safer structures. Call us on +44 (0) 1425 655027