Sub-250g Drone Line of Sight Rules in the UK

What VLOS Means Under CAA Rules

Visual Line of Sight, commonly abbreviated to VLOS, is one of the fundamental requirements for all drone flights in the CAA Open Category. The rule applies equally to sub-250g drones and heavier aircraft. Your drone weight provides no relaxation of this requirement.

The CAA defines VLOS as the remote pilot being able to continuously monitor the unmanned aircraft visually, without the aid of devices other than corrective spectacles or contact lenses. You must be able to determine the drone orientation, direction of flight, speed, and position relative to other aircraft, people, vehicles, and structures.

Critically, this means you cannot rely on:

• The First Person View (FPV) camera feed on your controller or phone screen as your sole means of monitoring the drone.
• Binoculars, telescopes, or any magnification devices to extend your visual range.
• A spotter alone. While a spotter can assist you, the remote pilot (the person holding the controls) must personally maintain VLOS at all times.

Practical VLOS Distance for Sub-250g Drones

The CAA does not specify a fixed maximum distance in metres for VLOS, because the practical range depends on many variables. However, for sub-250g drones, realistic VLOS distances are often shorter than pilots expect.

Factors that affect your VLOS range:

• Drone size: Sub-250g drones are small by definition. A DJI Mini 4 Pro, for example, has a wingspan of approximately 30cm. At 300-400 metres, it becomes extremely difficult to see with the naked eye.
• Weather and light conditions: Overcast skies, haze, rain, and low sun all reduce visibility. A drone that is easy to spot at 200m on a clear day may be invisible at 100m in light fog.
• Background contrast: A light-coloured drone against a bright sky is harder to see than a dark drone against clouds. Consider what your drone looks like from below at distance.
• Time of day: VLOS range drops dramatically in twilight and darkness, even with LED lighting fitted.

As a general guide, many experienced pilots find that sub-250g drones become difficult to track visually beyond 200-300 metres in typical UK weather conditions. In poor visibility, the practical limit may be 100 metres or less.

FPV Flying and VLOS

First Person View (FPV) flying, where the pilot wears goggles showing the drone camera feed, is popular among racing and freestyle pilots. However, flying solely through FPV goggles violates the VLOS requirement.

If you wish to fly FPV with a sub-250g drone in the Open Category, you must have a competent observer who maintains direct visual contact with the drone at all times. The observer must be positioned next to you and be able to communicate with you immediately to provide guidance and warnings.

Important distinctions about FPV operations:

• The observer is not a substitute for the pilot maintaining VLOS. In formal CAA guidance, the remote pilot should still maintain VLOS, with the observer providing additional safety monitoring.
• The observer must have an unobstructed view of the drone and the surrounding airspace.
• Both pilot and observer must agree on a clear communication protocol before flight.

What Happens If You Lose Visual Contact

If you lose sight of your drone during a flight, you should take immediate action:

1. Stop moving the drone: If your last known position was safe, hover in place. This prevents flying into unknown obstacles.
2. Use return-to-home: Most modern drones have an automatic return-to-home function. Activate it to bring the drone back to a known location where you can re-establish visual contact.
3. Do not continue the flight blind: Continuing to fly using only the camera feed while you have lost direct visual contact is not compliant with VLOS rules and is dangerous.
4. Descend if safe: If you are confident the area below is clear, descending slowly may help you locate the drone as it gets closer.

Beyond Visual Line of Sight (BVLOS)

Flying Beyond Visual Line of Sight is not permitted in the Open Category for any drone, regardless of weight. BVLOS operations require an Operational Authorisation from the CAA under the Specific Category, which involves detailed risk assessments, specific operating procedures, and potentially additional equipment such as detect-and-avoid systems.

For recreational and standard commercial sub-250g drone pilots, BVLOS is simply not available. The technology and regulatory framework are evolving, but as of 2026, VLOS remains mandatory for Open Category operations.

Tips for Maintaining VLOS

• Choose a flying position with a clear, unobstructed view of your intended flight area.
• Avoid flying directly above yourself. Craning your neck upward for extended periods causes fatigue and makes it harder to judge position.
• Use orientation lights on your drone (red/green navigation LEDs) to help determine which direction it is facing.
• Plan your flight route before take-off. Knowing where the drone should be at each point makes it easier to track visually.
• If flying near trees or buildings, keep the drone to one side of the obstacles rather than behind them from your perspective.
• Consider wearing a sun visor or polarised sunglasses (which still count as corrective lenses) to reduce glare.