Visual line of sight (VLOS) is one of the foundational requirements of Part 107. Under 14 CFR 107.31, a drone must remain within the visual line of sight of the remote pilot in command (RPIC) -- or a visual observer working with the RPIC -- at all times during flight.
What does "visual line of sight" actually mean? And how does it interact with FPV flying, long-range operations, and the growing world of autonomous drones?
What VLOS Requires
The FAA defines visual line of sight as the ability to:
- See the aircraft with unaided vision (corrective lenses are permitted)
- Know its location at all times
- Determine its attitude and flight path well enough to maintain safe flight
- Detect and avoid collisions with other aircraft
This last point is the safety purpose of VLOS. Without unaided sight of your drone, you cannot reliably see and avoid manned aircraft that may enter your flight path. ATC does not track small UAS at low altitude, so the collision avoidance responsibility falls entirely on the PIC.
"Unaided vision" is key. Binoculars, spotting scopes, and FPV goggles do not satisfy VLOS on their own.
FPV Flying and VLOS
Flying with first-person view (FPV) goggles is legal under Part 107 only if a visual observer maintains unaided visual contact with the aircraft at all times while the pilot wears the goggles.
The FPV pilot cannot satisfy their own VLOS requirement through the camera feed. The visual observer must:
- Have continuous unaided visual contact with the drone
- Be in communication with the FPV pilot (typically radio)
- Be able to alert the pilot to traffic, obstacles, and other hazards
A single pilot flying FPV with no visual observer is not compliant with Part 107 -- even if the camera shows the drone clearly.
Recreational flyers under 44809 have slightly different rules: some community organizations (like AMA) have specific FPV provisions. But Part 107 commercial operations require the visual observer arrangement described above.
How Far Is VLOS in Practice?
There is no specific distance limit in the regulations -- VLOS is a functional requirement, not a numerical one. In practice, the limits depend on:
Aircraft size and visibility markings. A small gray drone at 400 feet is nearly invisible to the human eye even in good conditions. High-visibility paint, LED lighting, and contrasting colors extend the effective VLOS range.
Lighting conditions. On a clear, sunny day with good contrast, a mid-size drone at 400 feet AGL may be visible at 1,000-1,500 feet horizontal distance for a pilot with good vision. In haze, overcast conditions, or facing into the sun, that range drops dramatically.
Altitude. At 400 feet AGL, a drone is nearly at the limit of most pilots' reliable unaided visual range. At 200 feet, visibility is much better.
A conservative practical VLOS range for most drones is about 400-500 meters. Some research suggests pilots can track high-visibility aircraft to about 800 meters in good conditions.
The legal test is whether you can actually determine the aircraft's attitude and flight path to maintain safe flight and avoid collisions -- not whether you can technically see a dot.
Visual Observers
A visual observer (VO) can extend your operational footprint. Under Part 107, the VO is:
- Located at a different position than the RPIC
- Maintaining unaided visual contact with the UAS
- Communicating with the RPIC to relay position, attitude, and hazard information
Multiple visual observers can be used to cover a larger area. However, the RPIC must still be able to immediately take control of the aircraft -- the overall operation must remain within the combined VLOS coverage of the RPIC and VO team.
Visual observers do not hold pilot certificates and do not need to be Part 107 certified.
Beyond Visual Line of Sight Operations
BVLOS operations (flying beyond visual line of sight) require a Part 107 waiver from the FAA under 14 CFR 107.200. The FAA approves BVLOS waivers for specific operations where the operator demonstrates an equivalent level of safety through alternative means -- typically involving:
- Detect-and-avoid technology (radar, ADS-B, or camera systems)
- Remote monitoring infrastructure
- Coordination with ATC
- Defined corridors with ground observer networks
BVLOS waivers are routinely granted for pipeline inspection, power line surveying, agricultural operations, and infrastructure monitoring. The application is submitted through DroneZone and requires a detailed safety case specific to the proposed operation.
The FAA also issued a final rule in 2023 creating pathways for BVLOS at low altitudes in controlled conditions (the "BVLOS beyond a network" rulemaking). This is an evolving regulatory area as drone delivery and autonomous operations expand.
Night VLOS
At night, VLOS has additional considerations. You must still be able to see the aircraft clearly enough to determine its attitude and heading. In practice, this usually means the aircraft's navigation lights are your primary reference.
Anti-collision lights visible from 3 statute miles in all directions are required for night operations (14 CFR 107.29). Those lights serve dual purposes: making the aircraft legal and making it trackable at night. If you cannot determine which way the aircraft is pointed from its lights, you have effectively lost VLOS.
Checking Conditions Before Your Flight
VLOS is affected by visibility, ceiling, sun angle, and haze. A preflight check that includes current visibility (from METAR data) helps you assess whether conditions support safe VLOS operations for your planned altitude and distance.
UAS SkyCheck includes current METAR visibility in the preflight result along with a weather-based penalty if visibility drops below FAA minimums. Free, no account required.