What Does VLOS Mean in a Drone Context?

What Does VLOS Mean in a Drone Context

Unmanned aerial vehicles, more commonly known as drones, have exploded in popularity in recent years. From hobbyists to professionals, drones are being used for aerial photography, surveying, inspection, and many other applications. However, operating a drone safely and legally requires understanding some key terminology, specifically the concept of VLOS – Visual Line of Sight.

What is VLOS?

VLOS stands for Visual Line of Sight. This refers to the requirement that the remote pilot or observer must be able to see the drone with their own natural vision, without any visual aids such as binoculars or telescopes. In other words, the drone must be close enough that the pilot can continuously see it and monitor its flight path.

This is in contrast to BVLOS, which stands for Beyond Visual Line of Sight. BVLOS operations involve drones being flown farther away, to the point where the pilot can no longer see it. Advanced technological solutions are required for BVLOS, such as an onboard camera that streams video to the pilot or automated flight controls.

Simply put:

  • VLOS: The remote pilot can directly see the drone at all times during flight.
  • BVLOS: The drone is too far away to be seen. Additional technologies are needed to control and monitor the flight.

Why is VLOS Important for Drone Pilots?

Maintaining VLOS during drone operations is critical for several reasons relating to safety and regulations:

Safety Concerns

  • Seeing the drone’s location allows the pilot to steer clear of any potential hazards or collisions. This could include trees, buildings, power lines, aircraft, people, or wildlife.
  • Monitoring the drone visually means the pilot can adjust its path if environmental conditions change, like if high winds arise.
  • Keeping the drone nearby provides the pilot with better ability to take manual control or land immediately if any issues occur.
  • Losing sight of the drone risks losing control and not knowing where it may end up or what damage it could cause.

Legal Requirements

  • In most countries, regulations mandate that hobbyist and commercial drones must be flown within VLOS. There are exceptions for advanced users with proper authorizations.
  • Flying a drone BVLOS without approval is illegal and can result in large fines. Maintaining VLOS keeps a pilot compliant.
  • Insurance policies generally require following VLOS rules. Otherwise, coverage may be denied for accidents and liability.

Limitations on Drone Operations

  • The actual possible distance for VLOS varies based on factors like weather, drone size, and pilot vision. But in general, most drones have a practical VLOS range under 1 mile.
  • Flying BVLOS can enable going much farther but requires advanced equipment, training, licensing, and waivers. Regular hobby drones are limited to staying nearby.
  • Operational restrictions based on VLOS impact what drone pilots are able to do, requiring close proximity to the drone.

How to Maintain VLOS During Drone Operations

Keeping a drone within visual line of sight takes mindfulness and preparation by the remote pilot. Here are some tips to help maintain VLOS:

Choose Open Locations

Pick flying sites with a wide, open surrounding area, avoiding densely populated spaces or heavily forested zones. Open fields, beaches, or deserts are ideal for maximum visibility.

Use Observers

Having a visual observer who assists the pilot can greatly help maintain awareness. The observer should be positioned to have eyes on the drone whenever the pilot cannot. Effective communication between the two is critical.

Orient Your View

Pilots should orient themselves to keep the drone in view as much as possible. This may require physically turning as it moves farther away. The observer can provide directional guidance.

Never Fly Too High

Resist the temptation to fly at maximum altitude, as this shrinks the drone from view. Stay under 400 feet to keep it visible. Lower may be required by regulations.

Stay Stationary

If manually piloting, avoid moving around while also moving the drone itself. Keeping the pilot static makes it easier to retain line of sight.

Use a Landing Zone

Designate a safe, visible landing area to return to each time. Trying to land while moving about risks disorientation and loss of sight.

Monitor Conditions

Adjust the distance and altitude based on conditions like sunlight glare, clouds, rain, smoke, and haze that can obstruct visibility. Stop immediately if sight is compromised.

Use a Spotter

If conditions make VLOS difficult, have a spotter follow the drone via direct sight to ensure its position is known, especially when landing.

Leverage Technology

Various tools can aid VLOS, like bright drone lights, anti-collision strobe lights, GPS trackers, and body-worn cameras streaming first-person video to the pilot. Know the regulations on what technologies can assist before using them.


Maintaining visual line of sight is an essential element of safe and legal recreational and professional drone operations. VLOS allows the remote pilot to visually monitor the aircraft at all times during flight. This minimizes risks and complies with regulations. While advanced users can gain authorizations for expanded BVLOS drone uses, standard hobby and commercial flights must remain close enough to see. Employing strategies like using observers, carefully selecting locations, and leveraging supportive technologies can help drone pilots maintain critical VLOS and safely get the most out of their drones.

Frequently Asked Questions

Q: What does VLOS mean in drone flying?

A: VLOS stands for Visual Line of Sight, which means that the drone must be visible to the pilot at all times during the flight.

Q: What is the maximum distance for VLOS drone operations?

A: There is no specific maximum distance for VLOS drone operations, but the drone must remain within the pilot’s line of sight at all times.

Q: Why is VLOS important for drone pilots?

A: VLOS is important for drone pilots to ensure safety, comply with regulations, and avoid limitations on drone operations.

Q: What are the legal requirements for VLOS drone operations?

A: The FAA requires that drones remain within the pilot’s line of sight during flight, unless the pilot has a waiver for BVLOS operations.

Q: What are the limitations of VLOS drone operations?

A: VLOS drone operations are limited by the pilot’s ability to maintain visual contact with the drone, which can be affected by weather conditions, terrain, and other factors.

Q: How can drone pilots maintain VLOS during flight?

A: Drone pilots can maintain VLOS by keeping the drone within their line of sight, using binoculars or other tools to enhance visibility, and avoiding obstacles that could obstruct their view.

Q: What tools and technologies can assist with VLOS drone operations?

A: Tools and technologies that can assist with VLOS drone operations include GPS, obstacle avoidance sensors, and first-person view (FPV) cameras.

Q: What is the difference between VLOS and BVLOS drone operations?

A: VLOS drone operations require the drone to remain within the pilot’s line of sight, while BVLOS drone operations allow the drone to fly beyond the pilot’s line of sight with the use of technology and special waivers.

Q: What are the safety concerns with VLOS drone operations?

A: Safety concerns with VLOS drone operations include collisions with other aircraft, loss of control due to poor visibility, and crashes caused by pilot error.

Q: How can drone pilots ensure safe VLOS operations?

A: Drone pilots can ensure safe VLOS operations by following FAA regulations, maintaining good visibility, avoiding obstacles, and practicing safe flying techniques.

Was this article helpful?

Similar Posts

Leave a Reply