Commercial jets are usually de-iced by spraying them with hundreds of litres of glycol before take-off. This process involves large teams of ground staff that inspect the aircraft and take weather conditions into account. However, this approach is clearly not possible once the plane is airborne. Most large aircraft are currently fitted with electromechanical ice sensors that detect ice through its damping effect on the vibration of a wire. However, these sensors are bulky, which makes them impractical for light aircraft because they can severely disrupt the airflow during flight. Furthermore, it is not possible to fit these sensors to the rotating blades of a helicopter.
Now, Martin Lawrence and co-workers at Cambridge Optical Sciences in the UK have developed a fibre-optic device that uses the reflection of light to detect ice. The work is part of an European Union collaboration called ACIDS.
In the September issue of Physics World Matthew Chalmers describes how this ice sensor could be used to improve aircraft safety.