One of the most fundamental rules governing small unmanned aircraft system (sUAS) operations under 14 CFR Part 107 is the visual line of sight (VLOS) requirement. Simply put, the remote pilot in command (RPIC), the visual observer (VO) if one is used, and the person manipulating the controls must be able to see the drone with their own unaided eyes throughout the entire flight. This single rule shapes almost every other operational decision a Part 107 pilot makes — from how far out the aircraft can fly, to how weather and lighting affect legality, to when a waiver becomes necessary.
Understanding VLOS deeply is not just about passing the FAA Aeronautical Knowledge Test; it is the cornerstone of keeping the National Airspace System (NAS) safe as unmanned aircraft become more common. A pilot who genuinely understands what VLOS demands — and why — will make better decisions in the field every single time.
What VLOS Actually Requires
Under 14 CFR §107.31, the RPIC, any VO, and the person manipulating the flight controls must maintain visual line of sight with the unmanned aircraft. This means being able to see the aircraft at all times, using nothing more than natural vision — with or without corrective lenses (glasses or contact lenses are permitted because they correct to normal vision, not enhance it beyond normal). The rule specifically states that the visual contact must be unaided.
What does that unaided requirement exclude? It excludes binoculars, telescopes, monoculars, or any other magnifying optical device used to extend the range at which a pilot could otherwise see the drone. You may use such devices momentarily to scan for traffic or gather situational awareness, but you cannot rely on them to maintain the primary VLOS requirement. If you can only see your drone because you are looking through binoculars, you are not in compliance with Part 107.
The rule also means that first-person view (FPV) goggles or screens alone do not satisfy VLOS. Looking at a live video feed from a camera mounted on the drone — even a very good one — does not constitute visual contact with the aircraft itself. The pilot's eyes must be on the actual drone in the sky, not on a screen. However, FPV can be used as a supplement provided a VO who is in direct communication with the RPIC is maintaining VLOS of the aircraft.
The Role of the Visual Observer
Part 107 allows, but does not require, the use of a visual observer (VO). Under §107.33, a VO may assist the RPIC in maintaining situational awareness of the drone and the surrounding airspace. Critically, VLOS responsibility can be shared across the team — meaning the VO can be the person maintaining eyes on the aircraft while the RPIC focuses on other tasks like managing the control station — but the team as a whole must always have someone with unaided visual contact of the aircraft.
Communication between the RPIC and any VO must be direct and continuous. They must be close enough to each other that they can speak and be heard without electronic assistance. Passing instructions through a radio relay to a VO who is far away does not meet the standard of the rule. Both the RPIC and VO must also be co-located at the same launch/control point — the regulation does not allow the VO to be stationed at a remote location simply to extend the visual range of the operation.
This is a frequently tested distinction: a VO extends situational awareness, but cannot be used as a workaround to extend the effective range of the operation beyond where VLOS is actually achievable by the team at the control station.
Why VLOS Exists — The Safety Rationale
The VLOS rule is grounded in the same principle that keeps manned aviation safe: a pilot must know where their aircraft is, what attitude it is in, and what is around it. When a remote pilot can see the drone directly, they can immediately detect an unexpected change in orientation, a sudden gust pushing the aircraft toward an obstacle, or the approach of a manned aircraft that the onboard sensors did not detect. This awareness cannot be fully replicated by a video feed, which has a limited field of view, potential latency, and no peripheral awareness.
The FAA designed Part 107 to integrate sUAS into airspace that is also used by manned aircraft — commercial airliners, general aviation planes, and helicopters all share the same sky. A drone pilot who loses visual contact with their aircraft cannot react effectively to avoid a mid-air conflict. The VLOS rule is the primary safety backstop that makes drone operations compatible with existing aviation activity.
Key Numbers, Conditions, and Rules
- Altitude limit: sUAS operations under Part 107 are generally limited to 400 feet above ground level (AGL). At that altitude and beyond typical lateral distances, maintaining genuine unaided VLOS becomes practically difficult, which naturally constrains the operational envelope in a safety-compatible way.
- Daylight and civil twilight: VLOS can only be maintained when there is sufficient light to actually see the aircraft. Part 107 limits operations to daylight hours or civil twilight (30 minutes before official sunrise to 30 minutes after official sunset, local time), and during civil twilight the drone must be equipped with anti-collision lighting visible for at least 3 statute miles.
- No corrective lenses restriction: Glasses and contacts are permitted since they restore normal vision rather than enhance beyond it.
- Binoculars prohibition: Optical aids cannot be used as the primary means of maintaining VLOS.
- FPV alone is insufficient: A live video feed does not substitute for direct visual contact unless a VO is simultaneously maintaining VLOS and communicating directly with the RPIC.
- Weather visibility: Minimum flight visibility for Part 107 operations is 3 statute miles from the control station. Operating in reduced visibility that prevents seeing the aircraft clearly would violate VLOS regardless of whether the 3-mile visibility minimum is technically met.
- Cloud clearance: sUAS must remain at least 500 feet below clouds and 2,000 feet horizontally from clouds — flying into or near clouds would compromise VLOS and violates the regulation.
Beyond Visual Line of Sight (BVLOS)
Operations that extend beyond what can be seen with the unaided eye from the control station are called Beyond Visual Line of Sight (BVLOS) operations. These are not permitted under standard Part 107 rules. To conduct BVLOS operations, a remote pilot or operator must obtain a Part 107 waiver from the FAA under §107.200. The waiver application must demonstrate that the proposed operation can be conducted safely without the VLOS requirement — typically through the use of detect-and-avoid technology, ground-based radar, ground observers along the route, or other equivalent safety mitigations.
BVLOS waivers are not easily granted. The FAA evaluates them carefully, and the burden of proof is on the applicant to show safety equivalence. This is important context for the knowledge test: understanding that BVLOS is a waivable rule — not an absolute prohibition — but that it requires formal FAA approval before any such flight takes place.
Common Test Traps
- FPV goggles satisfy VLOS — FALSE. FPV alone never satisfies VLOS. It requires a VO maintaining direct visual contact and direct communication with the RPIC.
- Binoculars can be used to maintain VLOS — FALSE. Binoculars can be used momentarily to scan, but cannot serve as the primary means of maintaining visual contact with the aircraft.
- A VO can be stationed far away to extend operational range — FALSE. The VO and RPIC must be able to communicate directly (without electronic relay) and are co-located at the control station.
- Civil twilight operations are prohibited without a waiver — FALSE. Civil twilight operations are allowed under standard Part 107, but the drone must display anti-collision lighting visible for at least 3 statute miles.
- BVLOS is absolutely prohibited — FALSE. BVLOS is prohibited under the standard rule but can be authorized through an FAA waiver under §107.200, provided the applicant demonstrates equivalent safety.