Commercial aircraft exterior lighting

Commercial aircraft exterior lighting – let there be light

Tim Takeoff
19.10.2020
5 minutes

Even if it sounds totally banal at first, and you can quickly distinguish a satellite, a star or a flashing airplane in the starry sky, the illumination of a commercial airliner is still quite complex.

Flying in the dark may be scary for some, but for pilots it’s no rocket science. A multitude of lighting elements along the aircraft help to achieve this. Each lamp serves a specific purpose and helps all participants in air traffic.

From halogen to LED technology

From a technical point of view, modern airplanes increasingly rely on LED technology. Older models of course still have classic systems, which are gradually disappearing. They are all connected to the on-board power supply of 115V.

Taxi & turnoff lights

If you start at the front part of the aircraft, you will find different lamp systems already on the nose wheel, depending on the type of aircraft. The “taxi light” is located in front of the aircraft. It not only lights the taxiways, but also signals to all other participants that the aircraft on the ground is moving and wants to taxi. In some aircraft types, the light is coupled to the steerable nose wheel so that it swivels along when the aircraft turns into a curve.

If this is not technically feasible, such aircraft have an extension to the taxi-light, the so-called “turnoff lights”. This does not mean that they should always be switched off, but they help the pilot to turn. Depending on the airline the procedures differ. Some only switch these lights on as needed, others leave both taxi and turnoff lights on during the entire taxiing process. If the aircraft stops, it is “good airmanship”, as pilots call it, to switch off the taxi lights. A typical light source has a power output of about 400 watts.

Things get serious: the landing lights

To further assist in improving visibility at night, “takeoff & landing lights” are used near the runway and below 10,000 feet. They are activated by the pilot as soon as take-off clearance is given. A wide beam angle and a higher output of over 600 watts then illuminate the runway during take-off and landing.

Since these lights can quickly dazzle other participants, they are switched off when taxiing or when an oncoming aircraft is on the ground. Similar to the high beam of a car. Some aircraft can even fold the landing lights out and back in again because they are not integrated into the front edge of the wings or landing gear (e.g. Airbus A320).

Commercial aircraft exterior lighting

Lighting for emergencies and control

The white, flat lamps are joined by two further categories:

One can be found in front of the wings. These lamps are usually slightly angled and when activated can cover the area along the leading edge of the wings up to the jet engine. These lamps, called “wing lights”, help to check for suspected damage or ice build-up during flight. In a passenger aircraft, this task can also be delegated to a flight attendant after the pilots have switched on the lights.

Advertising for safety? The “logo light”

The second wing illumination is found on the tail fin, or more precisely integrated in the tailplane of the jet. Even if you think that this is just a clever advertising measure, the tail unit lighting with the “logo light” also fulfils another task. The large area is very well visible at night, because in the dark other airplanes are best recognized from the side.

The “logo light” can be helpful, for example, when an aircraft is waiting at the runway 90 degrees offset at the landing for clearance to roll up. This gives the landing aircraft a good overview of whether its colleagues have understood everything correctly and the jet is not rolling into the runway unintentionally. But let’s not kid ourselves, everyone here does a little advertising!

The beacon

One of the most important lighting elements on the floor is a red flashlight, the “beacon”. As soon as the aircraft is set in motion, whether towed or starting the engines, the beacon is switched on. A red flashlight, both above and below the fuselage, signals to all persons in the vicinity of the aircraft: Attention, something is about to happen! Distance is required.

Navigation lights – important for yourself and others

The small lamps at the wing tips and the outermost tail of the aircraft are particularly relevant to safety in the air. Here one finds different groups of lamps.

The very well-known flashlight, the “strobe light”, is certainly one of the most visible elements. It is first used on an active runway, but then during the entire flight. It is very eye-catching and therefore it works well over long distances. In the air you can recognize foreign airplanes very quickly and effectively.

Towards me, or away from me? – “position lights”

In order to determine not only whether, but also in which direction a foreign aircraft is heading, the navigation lights, “position lights” are integrated in the wingtip and tail. You will find a green light on the right side, a red light on the left side and a white continuous light in the tail. They have a beam angle of 110 degrees to the front and 150 degrees to the rear (white only). With this you can now determine the flight direction of a foreign aircraft very precisely in the air.

For example, if you only see the flashes with an additional white continuous light, the foreign aircraft is flying in the same direction as you are. If it comes towards you, you will see red and green in reversed positions.

System redundancy everywhere

Like everything in aviation, the lighting system includes redundancies. There are several bulbs in each lighting element. If all bulbs of an element should fail, it is even possible that the jet may only be operated during daylight as long as it has not been repaired.

In the following YouTube video you will find some great night shots, which show the individual lighting elements again:

by Tim Takeoff

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