Lighting Systems on an aircraft is essential in this day and age. The loss of human life due to poor visibility would be an awful accident. This report explains the different types of lights fitted on aircrafts and also the different measures to make tall buildings and hard terrain more noticeable.
1. Introduction
Aircrafts are equipped with a range of lights that are used for safety, navigation and also to improve visibility during flight or when on the ground. There are also other factors such as runway lighting and aircraft warning lights on tall buildings that enables an aircraft to fly with an improved vision especially for night time flying.
2. Aircraft Lights and Beacons
There are two categories of external lights for an aircraft. The first category is navigation lights and the second category is takeoff and landing lights.
2.1 Navigation Lights
The navigation lights are at all times illuminated while the aircraft is in operation. Below are examples of such navigation lights.
2.1.1 Position Lights
Every aircraft has a steady light near the leading edge of each wingtip. When facing forward from the point of view of the pilot, the light on the left wingtip is red and that on the right wingtip is green. The difference in colours makes it possible for a pilot of another aircraft to distinguish which direction the aircraft is travelling. These lights are very useful during night time flying as it is harder to determine the direction the plane is going.
In addition to the green and red lights discussed above, a lot of aircrafts are also equipped with other steady white lights in different areas. In particular, big airliners will normally have these lights on the trailing edge of each wingtip. Such lighting is also sometime fitted along the trailing edges of the horizontal tail. The very rear of the fuselage or the top of the vertical tail is also a very popular location. The main function of these steady white lights is to improve the aircraft's visibility from behind.
2.1.2 Anti-Collision Beacon Lights
Two beacons lights are placed near the centre of the fuselage. One of them is located at the top and the other one at the bottom. These beacons are reddish orange in colour and produce a flashing effect by rotating. These lights are switched on just before the engines are started and will remain active until the last engine is turned off. The lights also help as a safety measure to ground employees that the engines are in operation.
2.1.3 Strobe Lights
These high intensity strobe lights flash a white coloured light and they are situated on each wingtip. These lights are very bright and are intended to draw attention during flight. They can also be used on the ground to make the plane more noticeable. The amount of strobes fitted normally depends on the size of the aircraft.
2.1.4 Wing Lights
Most airliners are fitted with lights along the root of the wing's leading edge. These can be used to light up engine pylons and wing during flight. These lights may also be used during landing and takeoff or to inspect the wings for any damage during flight. Pilots can also inspect any ice formation on the wings and slats that might build up with the aid of these lights.
2.1.5 Logo Lights
Most commercial aircrafts are fitted with these lights. They are not required but common and are often situated at the tips of the horizontal stabilizer. The steady white lights are used to light up the company's logo painted on the vertical tail. The main function of these lights is safety as the brightness emitted helps to make the plane more noticeable . It is also useful for advertising.
2.2 Landing and Takeoff Lights
Theses lights are used to improve visibility when the aircraft is on or close to the ground. The following are examples of these lights.
2.2.1 Taxi Lights
A bright white light is situated on the nose landing gear strut of most aircrafts. This lamp is usually turned on whenever the plane is in action on the ground for improved visibility during taxi, takeoff and landing.
2.2.2 Wheel Well Lights
Some aircrafts are fitted with extra lights in the nose and main gear wheel wells. These lights provide primary assistance at night to ground employees in making pre-flight inspections.
2.2.3 Landing Flights
These lights are bright white lights and are normally fitted to most aircrafts for improved visibility during the landing approach. They can also be used to illuminate the runway at poorly lit airports. They are primarily used for night landings but also commonly used during day so as to make the aircraft more visible. The location of these lights can vary from plane to plane and may either be located in the wing root, in the outboard wing or along the front of the fuselage. Some planes are fitted with several sets of landing lights in more than one location.
2.2.4 Runway Turnoff Lights
These bright white lamps are usually situated in the leading edge of the wing root and are provided to give side and forward lighting during taxi and when turning off the runway. These lights are usually unnecessary but are most useful at poorly lit airports. They can sometime be used in flight if greater visibility is needed.
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3. Runway Lighting
Cleveland Hopkins International Airport was the first runway to have lights fitted in 1930. Runway lighting is normally formed by a line of lights which helps to guide aircrafts in taking off or coming in to land.
3.1 Types of Runway Lights
The details of some of the various types of lights used on runways is shown below.
3.1.1 Runway End Identification Lights
These are synchronised flashing lights fitted at the runway threshold. There are one on each side and normally face the approach direction.
3.1.2 Runway End Lights
These are a pair of four lights on each side of the runway and extend along the full width of the runway. They show green when seen by the approaching aircraft and re when viewed from the runway.
3.1.3 Runway Centreline Lighting System
These lights are fixed into the surface of the runway at 50 feet intervals along the centreline. They are white coloured except the last 3,000 feet, alternate white and red for the next 2,000 feet and red for last 1,000 feet.
3.1.4 Taxiway Centreline Lights
These lights are installed into the runway pavement and alternate green and yellow. The lights starts with a green light about the centreline of the runway.
3.2 Control of Runway Lighting System
Normally the lights are controlled by a control tower or a selected authority. Whereas some airfields/airports are equipped with a Pilot Controlled Lighting. This system enables the pilot to temporarily turn on the lights when the relevant authority is unavailable. This avoids the need for staff to turn the lights on at night or in other low visibility conditions.
4. Aircraft Warning Lights
These devices are of high intensity and are fixed to tall structures which are used as anti-collision measures. They make buildings more visible to passing planes and are normally lit at night although they may be used during the day.
4.1 Lamp Types
The types of lamps are classified in two forms. The first one are red lamps which are either illuminated at all times or turn on and off slowly within a cycle. The second type is white xenon flashers. Recently new regulation have been passes and implement the use of red lamps only. Therefore the white xenon flashers are being taken out slowly.
4.2 Positioning
These lights are normally fitted to most tall buildings or structures. they can be in the form of towers, television masts, electricity pylon, cranes and wind turbines. Some shorter structures which are situated near to airports may also require these lights.
The lights are generally arranged in bunches of two or more around the structure at precise heights. Normally a set is fitted at the top and then a few more sets are equally spread further down the building. The tallest structure in the European Union which is TV Tower Vinnytsia has nine sets of red lamps equally spread along the total height of the mast.
5. Regulations
The Federation Aviation Administration (FAA) has passed regulations regarding warning light requirements for night flying. Flying with reduced visibility causes safety hazards because buildings can present optical conflicts when seen from changing altitudes. The different regulations are shown below.
5.1 Position Lights
FAA requires an anti-collision lighting system consisting of flashing lights placed on both of the aircraft's wingtips.
5.2 Anti-collision Lights
The regulation mandate that the lights must meet the correct requirements for colour and intensity. They must be standard red or white .
Two wingtip strobe lights must be fitted that protrude beyond the wing tip and their light converging in front and back of the aircraft within 1200 feet.
A minimum of two strobe lights are necessary on the fuselage to receive the required vertical coverage.
One strobe light must be mounted on the vertical fin and a half red and half white lens is preferred.
5.3 Airport Lights
Most airports must use a flashing beacon light for night identification. Civil airports uses an alternating white and green beacon light. Military airports also have a similar setup but with a distinguishable quick white flash.
6. Conclusion
The lighting systems fitted to modern aircrafts has proved to be a necessity. Aircrafts and pilots would have great difficulty without the aids of the lights and systems embedded. The different measures and equipments provided on the ground is also vital as it greatly helps in poor visibility areas. The loss of human life would not be surprising if such systems and measures were not installed.
