Part 107 visual line of sight requirements: VLOS rules and visual observers

The FAA Part 107 visual line of sight requirements are the backbone of nearly every legal drone flight, and they are more demanding than "keep the drone in sight" suggests. The rule requires that the people responsible for the flight can see the aircraft well enough to know where it is, which way it is pointed, and whether it is about to become a hazard, using their own eyes. It is the mechanism by which a remote pilot detects other traffic and stays clear of it, and it is the reason so much of Part 107 works without additional equipment or approvals. Understanding exactly what the rule asks, and what a visual observer can and cannot do within it, keeps a program on the right side of the line.

This article covers what the visual-line-of-sight rule requires, why it exists, how visual observers fit into it, and how a program keeps crew roles straight so the flight was flown and watched by the right people. The rule is short, but the obligations packed into it are specific, and treating it as a loose guideline is how operators drift into a violation.

What the visual line of sight rule requires

Under 14 CFR 107.31, the remote pilot in command, the person manipulating the flight controls, and any visual observer must be able to see the unmanned aircraft throughout the entire flight. Seeing it is defined by purpose: they must be able to determine the aircraft's location, altitude, attitude, and direction of flight; observe the airspace for other traffic and hazards; and determine that the aircraft does not endanger anyone's life or property. That vision must be unaided, except for corrective lenses. Binoculars, a telescope, or a first-person-view headset cannot substitute for the required line of sight.

The detail that catches people is the "throughout the entire flight" part. The rule does not allow the aircraft to slip behind a building, over a treeline, or into a distance where the required determinations can no longer be made, even briefly, on the theory that it will come back into view. A pilot who cannot see the aircraft well enough to make those judgments at any moment falls out of compliance at that moment, which is why range, obstructions, and lighting all factor into planning a legal flight, and why the rule shapes how a mission is laid out on the ground.

Why the rule exists

The visual-line-of-sight requirement is the see-and-avoid mechanism for small drones. A small unmanned aircraft must yield the right of way to all other aircraft and may not operate so close to another aircraft as to create a collision hazard, and the way a remote pilot meets that duty is by watching the aircraft and the airspace around it. Without a certified detect-and-avoid system on board, the pilot's eyes are the sensor.

That single requirement carries a surprising amount of weight across Part 107. It is part of why night operations were allowed under standard conditions without a separate mitigation, because the FAA concluded that visual line of sight combined with anti-collision lighting and the other rules sufficiently addresses the risk. It is also the rule that beyond-visual-line-of-sight operations must overcome, which is why flying past the point of unaided sight requires a waiver built on an alternative means of detecting and avoiding traffic.

How visual observers fit in

A visual observer is a way to satisfy the rule with a second set of eyes, not a way around it. Under 14 CFR 107.33, a visual observer may be used, and when one is, the remote pilot in command must ensure the observer is able to see the aircraft in the manner the visual-line-of-sight rule specifies. The remote pilot, the person manipulating the controls, and the visual observer must coordinate to scan the airspace for collision hazards and maintain awareness of the aircraft's position through direct visual observation. Effective communication among them is essential, because an observer who cannot promptly relay what they see is not extending the pilot's awareness at all.

A visual observer widens where a crew can position itself and can keep eyes on the aircraft while the pilot attends to the controls, but it does not remove the requirement that someone maintains the required line of sight. This is also what makes first-person-view flight workable under Part 107: a pilot flying through a headset can do so as long as a visual observer maintains visual line of sight of the aircraft and can communicate with the pilot. The observer is filling the see-and-avoid role the headset cannot, and the operation stays legal only as long as that observer is doing the job.

Scoping VLOS across a crew and a program

Once an operation involves more than one person, the roles the rule names become real assignments. Someone is the remote pilot in command, someone may be manipulating the controls, and someone may be the visual observer, and each carries specific duties. A program running multiple crews needs to know who filled which role on which job, both to run the operation correctly and to answer for it afterward. When roles are assigned loosely, it is easy to end up with a flight where no one clearly held the visual-observer duty, the exact gap the rule is meant to close.

Access supports getting this right. When a program's platform is set up to give each crew member only the jobs they are assigned, the crew for a job, and the role each person holds, is defined before the flight rather than sorted out at the site. A record of who was the remote pilot in command and who kept eyes on the aircraft turns the roles the rule requires into a documented fact, which is far easier to stand behind than a memory of who was doing what when a question comes up.

Common mistakes in Part 107 visual line of sight

Letting the aircraft leave sight and expecting it to return. The rule requires the ability to see the aircraft throughout the entire flight. Allowing it to slip behind an obstruction or into a distance where the required determinations cannot be made is a violation the whole time it is out of view.

Using binoculars or a headset to satisfy the rule. Vision must be unaided except for corrective lenses. A telescope, binoculars, or a first-person-view headset cannot serve as the required line of sight, and relying on one leaves the operation out of compliance.

Treating a visual observer as a way around the rule. A visual observer helps satisfy the rule, not bypass it. The observer must be able to see the aircraft as the rule specifies and must communicate effectively, or the see-and-avoid duty is not being met.

Flying first-person view without a maintained line of sight. A pilot flying through a headset needs a visual observer who maintains visual line of sight of the aircraft and can communicate with them. Without that observer actively doing the job, the flight is not legal.

Leaving crew roles undefined. The rule assigns specific duties to the remote pilot in command, the control manipulator, and the visual observer. When roles are not clearly assigned, a flight can end up with no one holding the visual-observer duty, which is the exact gap the rule is meant to close.

FAQ

What do the Part 107 visual line of sight requirements require?

That the remote pilot, the person flying the aircraft, and any visual observer can see the aircraft throughout the flight well enough to know its location, altitude, and direction, observe the airspace for hazards, and determine it does not endanger anyone. Vision must be unaided except for corrective lenses.

Can I use binoculars or FPV goggles to maintain visual line of sight?

No. The required vision must be unaided except for corrective lenses. Binoculars, telescopes, and first-person-view headsets do not satisfy the rule. First-person-view flight is legal only when a visual observer maintains the aircraft's visual line of sight and communicates with the pilot.

Is a visual observer required under Part 107?

Not generally. A visual observer is optional for most operations, but when used, the observer must be able to see the aircraft as the rule specifies and coordinate with the pilot. A visual observer is required in practice to fly first-person view while keeping the operation legal.

How does visual line of sight relate to beyond-line-of-sight flying?

Beyond visual line of sight means operating past the point where unaided sight can meet the rule, which requires a waiver of the visual-line-of-sight requirement. That waiver rests on an alternative way of detecting and avoiding other aircraft, since the pilot's eyes can no longer serve that function.

Closing thought

The Part 107 visual line of sight requirements ask for more than a glance at the sky. They require that the people responsible for a flight can see the aircraft well enough to judge its position and keep it clear of others, with their own eyes, for the whole flight, and a visual observer extends that capability without removing it. Because so much of Part 107 rests on this rule, a program that assigns crew roles deliberately and records who held them keeps the see-and-avoid duty a documented fact rather than an assumption.

If you are running crewed drone operations where roles matter, FlybyOps was built for the operational record problem at the center of regulated drone work. Role-based access control, a project and job hierarchy with map-based scoping, a pilot registry with certification and currency tracking, and an append-only audit log are all part of how the platform keeps a record of who flew and who kept eyes on the aircraft.