Every time you see an aircraft fly through the sky at night you observe lights of different colors flickering in the sky. It is obvious that those flickering lights are the lights fitted on the exterior of the aircraft that have a significance of its own. These lights are engineered with 3 basic purpose in mind:
- to make the aircraft more visible to other aircraft,
- to improve pilot visibility during critical phases of flight or
- to provide illumination for some other specific purpose
It also happens that a light serves two purposes at a time.
Let us understand the significance of each light in detail:
1.1 Aircraft Visibility
These are the lights to enhance safety of aircraft in terms of visibility when on grond and when in air. They reduce the potential of collision, by making the aircraft more visible to other aircraft and other traffic on ground. They are:
a) Position Lights/ Navigation Lights:
Navigation lights consist of a red light on the left/port wing tip, a green light on the right/starboard wing tip and a white light on the aircraft tail. Dual systems are often installed to provide redundancy in the event of a bulb failure. The purpose of these lights is the help identify position of an aircraft.
All aircraft have red and green lights on the wingtips. Red is always on the way wing, green on the right. White position lights/ navigation lights are mounted on wingtips and/or the tail and face aft.
Position lights are often called “navigation” or “nav” lights, although they have nothing to do with navigation. They help a pilot to understand the direction of maneuver of an aircraft in air.
The spread of the navigation lights is illustrated in the image below:
- red light is projected above and below the horizontal plane through angle of coverage 110°
- green light is projected above and below the horizontal plane through angle of coverage 110°
- white light is projected above and below the horizontal plane rearward through angle of coverage 140°
How to identify:
The image below shows how an aircraft looks when viewed by pilot of an aircraft midair which helps the pilot to effectively identify the position of the aircraft.
b) Anti-Collision Beacon:
The aircraft beacon lights are red in colour and either flash or rotate to provide a pulsating warning light. They are normally installed in pairs with one on the top of the fuselage and the other on the bottom. The beacon is normally turned on prior to engine start and turned off after engines have been shut down. The purpose of this beacon is to alert the ground staff that the aircraft engine is on and safe distance is to be maintained.
c) Strobe Lights:
Strobe lights are usually positioned near the trailing edge of the wing tips and may also be installed on the tail of the aircraft. Strobes are high intensity white lights which flash at a regular interval. They are normally turned on when entering an active runway for takeoff and turned off when leaving the runway after landing.
1.2 Pilot Visibility
Landing on an aerodrome during conditions in which visibility of the pilot is compromised due to various weather conditions is not very uncommon. Thus there are lights fitted on the aircraft to help the flight crew to navigate safely on the aerodrome. They are:
a) Taxi Lights:
These are medium intensity lights usually installed on the nose gear strut and/or on each wing root. These are used the same as the car’s headlights. They light up the taxiway at night.
There may also be two special taxi lights, called runway turnoff lights, that point slightly left and slightly right of the aircraft nose to enhance visibility while making turns and illuminate obstacles on the left or right of the aircraft. They also illuminate high-speed runway exits as the aircraft decelerates during the landing roll out.
b) Landing Lights:
Landing lights are aimed to make the runway visible during takeoff and landing. These lights may be on mounted on the wings, landing gear strut or fuselage. In some installations, they are mounted in the leading edge of the while in others, they are extended and retracted from a cavity in the wing or fuselage. When landing, they start lighting up the ground about 200 feet or so above the runway. Where the AOM (Aircraft Operating Manual) allows, landing lights are normally turned off as the aircraft climbs through 10,000′ and are turned on again as it descends through 10,000′ on approach.
Depending upon the regional norm, landing lights are either switched on when entering the active runway or upon receipt of takeoff clearance. Landing and taxi lights are extremely bright. We have to be careful with them on the ground, especially at night. Turning on the lights when ground personnel are nearby can cause serious retinal damage.
You might have noticed, the landing lights are kept on for several minutes after take-off and before landing. Landing lights are so bright, they also make great anti-collision lights. When climbing or descending near airports, they are turned on so that other pilots can see the aircraft; they can be seen for miles, even in the daytime. When near cruising altitude, they may be shut off.
c) Wing Inspection Lights:
Wing inspection lights are mounted on the side of the aircraft fuselage, just forward of the wing root. They are aimed rearward to illuminate the leading edge and top of the wing. Their primary function is to help the crew and maintenance personnel inspect the wings for ice, snow, or damage. The lights are also effective for collision avoidance.
1.3 Specific Purpose Lights
Other than the above purposes there are lights installed for specific purposes too which are:
a) Logo Lights:
Logo lights are generally mounted on the upper surface of the horizontal stabilizer and are aimed to illuminate the Company markings on the tail of the aircraft. This is also the reason you are able to identify the airline while on ground at night.
2. How are these lights controlled?
The external lighting controls are located on the overhead panel within easy reach of either pilot. The taxi and two runway turnoff lights are on the left. The three big toggle switches on the bottom are the landing lights. The four black push switches control the position, anti-collision and wing illumination lights.
Hope you enjoyed reading the article!
Well as beautiful the aircraft lights are so are lights on ground at an aerodrome. Check them out with the link below: