夜晚看飛機時，你可能會注意到機翼兩端的紅色與綠色燈光，以及機尾的白色燈光。
這些燈光稱為航行燈（Navigation Lights，也稱 Position Lights），主要用途是幫助飛行員在夜間辨識其他飛機的相對位置與飛行方向。
一般飛機的航行燈有三個主要位置：
- 左側機翼為紅燈 🔴
- 右側機翼為綠燈 🟢
- 飛機機尾為白燈 ⚪
只要記住「左紅、右綠、後白」，就能輕鬆記住它們的位置。這種設計與船舶的航行燈原理類似，都是為了讓其他駕駛者辨識交通工具的方位與動向。
值得一提的是，航行燈是恆亮、不閃爍的；如果你看到的是閃爍的燈光，那是另一套「防撞燈」（機身上下方的紅色閃爍燈，以及機翼與機尾的白色閃爍燈），功能是讓飛機在遠處更容易被看見，並不是用來判斷飛行方向。
我們可以把飛機的航行燈想像成汽車的頭燈與尾燈。夜間開車時，看到白色頭燈，通常代表汽車正朝自己駛來；看到紅色尾燈，則通常代表汽車正遠離自己。飛機的航行燈也有類似的判讀方式，可以幫助飛行員初步判斷其他飛機的相對位置。
例如，我們可以透過航行燈的顏色與組合，來初步判讀其他飛機的相對位置與航向：
- 正面迎來：你會同時看到紅燈在右、綠燈在左，通常表示對方朝你飛來。
- 側向交會：通常只看到單一顏色的燈。看到紅燈，表示對方在你的左方；看到綠燈，表示對方在你的右方。
- 同向遠離：只看到白色尾燈，表示你在對方後方，對方正遠離你
當然，飛行員不會只靠航行燈掌握周遭空域的情況。實際飛行時，還會搭配多種設備與資訊來確保安全。例如：
- 空中交通管制（ATC）：利用雷達或其它監視系統掌握飛機的位置
- GPS 與導航系統：能協助飛機確認自身位置及規劃航線
- 空中防撞系統（TCAS）：則能在符合設備與運作條件時，偵測可能構成碰撞威脅的其他航空器，並提供交通或避撞提示
透過航行燈、目視觀察、航管資訊及機載設備的相互配合，飛行員才能更全面地掌握周遭空域的狀況，讓每一次飛行更加安全。
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The Red and Green Lights on Airplane Wings
When you look up at an airplane at night, you may notice red and green lights at the wingtips and a white light at the tail.
These are called navigation lights (also known as position lights). Their main purpose is to help pilots identify the relative position and direction of other aircraft at night.
Most airplanes have three main navigation lights:
- 🔴 Red light: On the left wingtip
- 🟢 Green light: On the right wingtip
- ⚪ White light: At the rear of the aircraft
This design is similar to the navigation lights used on ships. Both help others identify a vehicle’s position and direction of travel.
One interesting fact is that navigation lights are steady, not flashing. If you see flashing lights, they are part of the aircraft’s anti-collision lighting system. This includes red flashing lights on the top and bottom of the aircraft, as well as white flashing lights on the wingtips or tail, depending on the aircraft design. These lights help make the aircraft more visible from a distance rather than indicate its direction of travel.
You can think of airplane navigation lights as being similar to a car’s headlights and taillights. When driving at night, white headlights usually mean a car is coming toward you, while red taillights usually mean it is moving away. Airplane navigation lights work in a similar way and help pilots make an initial judgment about another aircraft’s relative position.
For example, the colors and combination of navigation lights can provide clues about an aircraft’s position and direction:
Head-on approach: You see both the red and green lights, with red on your right and green on your left. This usually indicates that the other aircraft is approaching you.
Side view: You may see only one colored navigation light. Seeing a red light means you are viewing the aircraft from its left side, while seeing a green light means you are viewing it from its right side.
Viewing from behind: If you see the white tail light, you are generally behind the aircraft, which is likely moving away from you. However, this does not necessarily mean it is flying directly away from you.
Of course, pilots do not rely on navigation lights alone to monitor nearby aircraft. They also use various systems and information sources to maintain flight safety.
Air Traffic Control (ATC): Uses radar and other surveillance systems to monitor aircraft positions and provide traffic instructions.
GPS and navigation systems: Help aircraft determine their own position and follow planned routes. However, GPS alone does not automatically show the positions of all nearby aircraft.
Traffic Collision Avoidance System (TCAS): Under the appropriate equipment and operating conditions, detects other aircraft that may pose a collision threat and provides traffic advisories or collision-avoidance guidance.
By combining navigation lights, visual observation, air traffic control information, and onboard systems, pilots can better understand the surrounding airspace and help make every flight safer.
