Why Do Airplanes Have Red And Green Lights? Here's What They're For
If you've ever been hanging out on a tall hill at night, you've probably seen some lights flashing in the dark sky above. No, it's not a mysterious UFO — the kind there are problems studying – spying on you. It's just an airplane flying overhead. And as with any vehicle, airplanes are equipped with a variety of exterior lights.
The most obvious ones are the plane's headlights, used to illuminate runways on red-eye flights. In addition, planes employ several kinds of small, colored lights on their bodies, particularly red and green lights on the tips of the wings. These look neat flying through the night, but they're not just there for aesthetic purposes. Those red and green lights play a vital role in aircraft navigation, ensuring that anyone watching from the ground, or in the sky or a control tower can immediately glean a plane's heading, even if it's pitch-black outside.
The colored lights let you determine a plane's position in the dark
The use of colored lights on an airplane is a holdover from maritime procedures. Large boats employ similarly-colored navigational lights on their sides, which lets other boaters determine where the boat is relative to themselves. That was a small, yet vital technological development for safe exploration and travel. It's the same principle with red and green lights on planes, just from further away.
Most planes have a red light on the left wingtip and a green light on the right one. These lights help both aircraft controllers and other pilots see the planes around them, even at night or in poor weather. The lights need to be different colors because they let an observer immediately determine which side of the plane they're looking at, even if it's too dark to see the rest of the plane.
For example, if you saw the red light on the right and the green light on the left, you'd know the plane is flying directly toward you. Or, if you were only able to see the green light, you'd know you're looking at the plane's right side.If both lights were the same color, you wouldn't be able to tell which side of the plane you're looking at, or if it's flying toward or away from you.