In recent years laser pointers have become readily available to the general public. More worryingly, there has also been an increase in the deliberate (and illegitimate) use of laser pointers to illuminate aircraft and air traffic control towers. This (slightly modified) Skybrary article provides information about laser (Light Amplification by Stimulated Emission of Radiation) devices and the potential hazardous effects their use can cause in navigable airspace in particular to pilots during critical stages of flight such as take-off and approach/landing.
The potentially hazardous visual effects of lasers are generally only visible during night time. The lasers produce an intense, coherent directional beam of light with wave lengths covering the visual spectrum of 400-700nm.
The main visual effects are:
Distraction and Startle: This occurs when an unexpected laser (or other bright light) can distract a pilot during a night time take-off or approach/landing.
Glare and Disruption: This occurs as the intensity of the laser light increases such that it starts to interfere with vision; night vision starts to deteriorate.
Temporary Flash blindness: This effect is similar to that experienced when looking at a bright camera flash. There is no injury, but a portion of the visual field is temporarily knocked out. Sometimes there are ‘afterimages’.
Factors Affecting Lasers in Aviation
- Time of day,
- Power of the laser,
- Colour of the laser,
- Distance and relative angle of the laser and aircraft,
- Speed of the aircraft and,
- Exposure time.
- Reducing the Hazard
There are several means employed to try to reduce hazards associated with lasers in navigable airspace:
Laser Light Hazard Reduction - Concentrates on preventing and keeping the laser light from being directed into navigable airspace especially that used by aircraft around airports and on known flight paths. In the US automated detection/avoidance systems are used to terminate or reduce the power of the lasers in certain circumstances; airspace observers or ‘spotters’ are also used to help keep the lasers away from in flight aircraft.
Regulatory Reductions - Include national measures to restrict the sale, carriage and use of lasers as well as amending existing laws and statutes. Educating the public in the safe use of pointers is also important as is providing warning labels on the laser devices (especially those above 5mW) about the dangers of shining lasers at aircraft. Some laser manufacturers are also actively engaged in strengthening the regulatory process in some countries.
Pilot Defences - Consist of pilots being trained in laser illumination recovery techniques (e.g. look away from the beam and do not try to find the source of the laser, engage autopilot, turn up cockpit lighting). Pilots should also check NOTAMs for notified laser activity along their flight plan route. Finally, pilots should report all laser illuminations to air traffic control and complete an Air Safety Report in accordance with company/national policies
Air Traffic Control Defences - Consist of air traffic controllers recognising a laser illumination (of the visual control room facility) and reacting accordingly. They should not try to identify the light source and should inform aircraft under their control about the laser illumination. As with pilots, air traffic controllers should report laser illuminations to their company/CAA in accordance with company and national policies.
Physical Defences - Could include the wearing of laser safety goggles to shield pilots’ eyes although their use is generally considered impracticable in most circumstances. Glare shields may also offer limited protection but again their use and effectiveness is questionable.
Regulations and Control - In the US, the FAA has established airspace zones around airports which limits the power of lasers used inside the zones.
- Laser Free Zones around the immediate environs of the airport;
- Critical Flight Zones covering 10nm around airports (light intensity < 5 microwatts per square centimetre (µW/cm²));
- and Sensitive Flight Zones (optional) where the FAA has specified that light intensity must be less than 100µW/cm².
Self Assessment Tool for Pilots
The CAA has developed a self-assessment tool for pilots that have been involved in a laser attack which can help determine whether they have sustained an eye injury. The Aviation Laser Exposure Self Assessment (ALESA) tool is freely available online as a downloadable file that pilots can print off and use straight away or keep in their flight bags.
The core of the test consists of a 10cm² grid that, when viewed from 30cm away, can be used to detect whether a pilot’s vision has been affected by the laser beam. When printed the grid should measure exactly 10cm x 10cm. The tool also includes guidance on when pilots should seek precautionary help from an eye specialist such as an optometrist or ophthalmologist.
More useful links and information
Below you find a cple of useful sources of information. Some may seem outdated, nevertheless the information they contain is still up-to-date.
- ALPA Laser Conference (2011)
- AeroSafety World (June 2012) - Lightning Strike Data
What does BeCA do?
Apart from providing our members with useful information we recommend our members to report every laser illumination via ATC and Air Safety Report (ASR). Furthermore we urge the BCAA, Department of Justice and the politcal to establish effective deterrents.