If you wish to contribute or participate in the discussions about articles you are invited to join SKYbrary as a registered user
Laser Interference in Aviation
From SKYbrary Wiki
A seminar on laser interference in aviation will be held at EUROCONTROL Headquarters in Brussels, 10-11 October 2011. The seminar is aimed at bringing together all stakeholder groups with a vested interest in this issue, so that they can consider adopting a collective approach to reducing the growing threat of unauthorised laser interference in aviation.
In recent years there has been a proliferation in the use of lasers outdoors for legitimate purposes such as laser shows and tests. More worryingly, there has also been an increase in the deliberate (and illegitimate) use of laser pointers to illuminate aircraft and sometimes air traffic control facilities.
This 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. 
- The airspace zones consist of:
- Laser Free Zones around the immediate environs of the airport (see figure);
- 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.
- The airspace zones consist of:
- Pilot Incapacitation
- Misuse of Lasers - Illumination of Aircraft and ATC Towers
- Unwanted Laser Illuminations (Hz26)
- ^ Murphy, Patrick (2009). Lasers and Aviation Safety. International Laser Display Association (ILDA)
- ^ EUROCONTROL SRC Doc 7 (February 2001): "Outdoor Laser Operations in Navigable Airspace" - EUROCONTROL.
There is a mass of further information available on the internet about lasers and the potential hazardous effects their use can cause in navigable airspace. The following references were used in the compilation of this article and provide a sound basis for further research into the phenomenon.
- IFALPA Medical Briefing Note 12MEBBL01 (April 2012): "The Effects of Laser Illumination of Aircraft" - International Federation of AirLine Pilots Associations (IFALPA).
- UK CAP 736 (November 2008): "Guide for the Operation of Lasers, Searchlights and Fireworks in United Kingdom Airspace" - UK CAA.
- The International Laser Display Association (ILDA) provides a wealth of information and associated links about lasers and aviation.
- AviAtion LAser exposure seLf-Assessment (ALesA), UK CAA
- Laser Pointers: Their Potential Affects on Vision and Aviation Safety
- Reducing the Threat of Laser Illuminations, an article in the Boeing AERO magazine, Q1 2010 issue
- FAA AC 70-2A 'Reporting of Laser Illumination of Aircraft'
- ICAO Doc 9815 'Manual on Laser Emitters and Flight Safety', First Edition 2003
- GACA AC 77-01 'Laser emissions that may endanger the safety of civil aviation'