Why Do Drones Have Red Lights? (Basics Explained)


You may have noticed red lights on some of the outside panels of your drone (or on one out at the park), and wondered what they signify. Drones are complex pieces of equipment, and have a lot of settings and modes that can be used for different uses, so the lights that you can see displayed on the drone hold quite a bit of significant information for users. So, what do the red lights on a drone mean?

Red LED lights on a drone may indicate battery levels, warnings, and errors, or may denote certain flight modes as well. Other colors on the drone, including green, blue, and white, and occasionally orange/yellow and purple can indicate additional information to the user as well.

Although red lights on a drone may indicate a variety of information for users, there are actually far more colors that flash in various ways to indicate different things. Stick around to find out the basics of drone LED lights, as well as what they may mean for drone users. 

What Does a Red Light on a Drone Mean?

Red lights on a drone are used to inform users of various problems or warnings, but the specifics may vary slightly depending on the exact make and model of the drone. In most cases, these color codes and patterns may be explained in the manual, but there are a few things that red lights commonly signify. The flashing pattern of the lights can also convey certain information about warnings or settings.  

Low battery

If the red lights are flashing slowly at a pace of around every 3 seconds, this commonly indicates that the battery is low or has fallen under 10.9V. Users should use this indication as a warning that the drone may run out of power soon, which necessitates that they should be charged. Users may not be able to return home with the battery at such levels. 

Critically low battery

If the red lights are flashing rapidly, this is usually a warning to indicate that the battery is about to run out of charge or has fallen below 10.6V. If your drone is flashing red lights rapidly during flight, and the cause is that the battery is reaching critically low levels, this does pose the risk of the drone dropping to the ground mid-flight. 

If you see this warning light, it’s a good idea to try to land the drone immediately wherever it is to avoid a damaging fall to the ground.

IMU errors

When a drone is flashing red lights periodically, it may also indicate that there is an issue with the IMU, which will need to be addressed in order for the drone to regain proper performance and functionality. 

Critical errors

If a drone simply has a red light that is not flashing but is solid, it may indicate a critical error that needs urgent attention. These errors may range in their specific natures, but a consistent red light is often the most common way to warn users that there is an error that needs to be addressed. 

Return Home Mode

Although there are many indicators of warnings and errors that use a red light, it’s not always an emergency signal. Some drones may also display a solid red light when the Return Home mode is active. 

Agility Mode

Some drone models may display flashing red lights in varying patterns when entering agility mode. In cases with normal operations and GPS locked, the red lights may all be solid. However, if GPS is lost, the red lights may flash rapidly for 2 seconds, after which it would flash once every second. 

Zone or Altitude Warnings

For some drones, a red light may appear in flashing variants to indicate that there may be an issue with the surrounding area. It may communicate various factors to warn pilots of harmful or hazardous zones, or to inform them that they are flying at dangerous altitudes.

What Other Color Lights are on Drones?

Drones utilize alternating colored LED lights to display a variety of information, some of which also alternate with red in various ways. The most common LED colors used in drones other than red are green, blue, and white. Some drones may have additional colors such as orange/yellow and purple for other uses.

Green

Green lights are usually used to indicate the battery level at startup, ranging from full green indicating a full battery to half green half red indicating 50% battery, for example. A solid green light commonly indicates a strong GPS connection on many drones as well. Green is also used when entering Smart Mode with GPS lock which will flash rapidly for 2 seconds after which it would flash every second. 

Blue

Blue lights generally indicate Blind Mode upon startup, or when entering Stability Mode with GPS lock which will flash rapidly for 2 seconds after which it would flash every second.

White 

White lights are used to indicate that the transmitter is off or is not bound to the drone, or to signify that emergency mode is active upon startup. Solid white lights may indicate that the GPS is off in Smart, AP, or Return Home modes. White is used in alternating flashes with other colors when GPS is lost in Stability and Agility modes. 

Anti-collision lights

These may be blinking or solid, and the color can range between green, white, or red, depending on the drone. Some drones even offer the option to change the color of these lights to your preferences, so that they are visible in varying lighting settings and scenarios. These lights are mainly for safety reasons as they make the drone far more visible to you and others in the area, which is why the FAA requires that they be used during twilight and nighttime hours.

Navigation lights

The navigation lights on a drone are solid and consistent, and they do not flash at all. These also range in color between green, white, or red, and this is commonly what is seen on a functional drone while it is in use regardless of the time of day. 

Orange/ Yellow

Orange lights usually indicate that compass calibration is required for the drone, which would flash or display in a solid manner upon startup. Flashing orange or yellow lights may also indicate no GPS connection on some drones. 

Purple

When certain modes such as the Return Home Mode or Follow Me Mode are active successfully, it would display steady lights in other colors. But, if GPS is lost during this mode, the drone may flash purple lights rapidly for 2 seconds after which it would flash every second. Some drones may also display solid purple lights when entering AP Mode, after which it would flash rapidly for 2 seconds after which it would flash every second intermittently. 

Part 107 and Drone Lights

For enthusiasts who are operating drones for commercial use, there are a number of regulations that will need to be adhered to in order to meet the FAA’s requirements, according to the Part 107 Small Unmanned Aircraft Rule. This includes the following:

  • Users must hold a Remote Pilot Certificate issued by the FAA to fly commercially.
  • Users must register their UAV with the FAA on the FAADroneZone website.
  • Users’ UAV weight cannot exceed 55 pounds at takeoff, inclusive of payloads.
  • Users may only fly in Class G airspace.
  • Users must keep their UAV within visual line-of-sight.
  • Users may not fly to heights exceeding 400 feet.
  • Users must use anti-collision lights to fly during twilight or low light hours.
  • Users may not fly at speeds exceeding 100 mph.
  • Users must yield right of way to manned aircraft.
  • Users may not fly from a moving vehicle unless in a sparsely inhabited zone.

While there are many requirements based on these regulations, there are some necessities in relation to the drone light’s functionality and visibility as well. Based on the necessities, all drones have to be equipped with anti-collision lighting if operated in low light hours for various safety reasons, but may still benefit from additional lights such as navigation lights.

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Anti-collision lights need to be high quality in terms of their visibility since they need to be consistently visible within the line of sight. Thus, simply having lights for the sake of ticking the box will not cut it, the LED lights need to be up to standard with regard to their luminosity. 

Thankfully, all of these requirements are reasonably practical to follow, and award users with the peace of mind that accompanies ensuring the safety of themselves and others, as well as the longevity of the drone itself. These requirements and legalities are the responsibility of each pilot, and ensuring the above will enable you to fly safely, skillfully, and legally.  

Drones are equipped with a variety of LED lights to ensure that users are aware of the condition of the components and internal workings at all times, and knowledge of these indicators is absolutely essential for ensuring that no harm comes to your drone or to others. Always make sure you are up to date with the LED communications for your specific drone by referring to the manual or contacting the manufacturer before operating your drone. 

Elizabeth Ciobanu

Editor-in-Chief. Elizabeth is a full-time (homeschooling!) mom of four, and serial entrepreneur in a variety of enterprises, one of which is producing content for Droneblog. If free time existed, she would love to spend more time on hobbies such as flying a drone.

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