Whether they drive one or not, most people know what the lights on a car are for. But how many times have you been to an airport or looked up at the sky and wondered what purpose some aircraft lights serve? First and foremost, unsprprisingly, aircraft lights are used to improve visibility, since being seen significantly improves the safety of a form of transport that is already the world’s safest, extensively controlled by Spanish, European, and international regulations and regulatory bodies. So here are the main lights on most commercial aircraft:
Main Aircraft Lights
Navigation Lights
Green, red and white in colour and mandatory since 1996, these are always used in flight between sunset and sunrise, at any time of day in poor visibility and whenever the aircraft is on the ground. They are located on the wingtips (at the furthest point possible) and indicate the relative position of the aircraft (i.e., where the plane is in relation to other aircraft). On the ground, this helps to identify where the plane is and in which direction it’s going. On the aircraft seen from behind, there’s a red light on the left wing and a green light on the right wing, each covering an arc of 110º. There is usually also a white tail navigation light, which is located at the far end of the aircraft and covers an angle of 140º. The 220º provided by the wing lights plus the 140º from the tail equals the 360º that makes the aircraft visible from any angle in the horizontal plane. By design, these lights must meet the regulatory requirements of these graduations.
Taxi Lights
White like the tail navigation light, these are usually located on the nose gear. When the aircraft is taxiing on an airport taxiway, they’re switched on to illuminate the taxiway, i.e., while the aircraft is moving on the ground and until it enters the runway. However, they may be kept on once on the runway for visibility reasons. Otherwise they’re switched off when the take-off and landing lights are activated.
Landing Lights
These are also used for takeoff. As mentioned before, they are switched on to illuminate the runway when the aircraft has received permission to take off or land; their white beams extend forward. Their function is to improve the aircraft’s visibility during takeoff and landing. They are also very powerful, at least 600 watts, and can be seen from several kilometres away. They are located either at the lower end of the wings next to the navigation and strobe lights or attached to the fuselage on larger jets. After takeoff, they are not required after reaching an altitude of 10,000 feet.
Anticollision (Beacon) Lights)
As the name suggests, these are lights that are activated to avoid the risk of collision, and are usually located at the top and bottom of the aircraft. Their key features are that they are red, flash intermittently, and are always used, day or night. In addition, beacon lights provide information to ground personnel. If they are on, it means that the engines have started or are about to start. In fact, switching on the beacon lights is part of the protocol or checklist before starting the engines.
Strobe Lights
These are located on the wingtips and on the tail of the aircraft. Their function is the same as the beacon lights. However, they are white and provide better visibility. Like beacon lights, they flash, but at regular intervals (three times per second for the wing and twice per second for the tail).
Other Commonly Used Lights
Widely used, but not mandatory:
Logo Lights
These are used to illuminate the airline’s logo on the fuselage
Runway Turn-off Lights
Supplementing the taxi lights, they’re white, located on the wings, and provide additional illumination during turns on the ground.
Wheel Well Lights (Dome)
These are installed on the landing gear and allow ground personnel to properly inspect the fuselage before each flight.
Wheel/Engine Scan Lights
Their function is like the wheel well lights (checking these two parts of the aircraft) and can also assist in flight by checking for damage.
Wing Lights
Also useful for inspections, and used by pilots to see the ground while passengers are boarding.
Cargo Compartment Floodlights
These are used to illuminate the cargo compartments on the ground during loading and unloading.