What does visual line of sight mean under 14 CFR 107.31, and can a remote pilot use binoculars to maintain it? Answer in under 100 words.

Details / How it works

Section 107.31 mandates that the remote pilot in command, the visual observer (if one is used), and the person manipulating the flight controls be able to see the small unmanned aircraft throughout the entire flight using vision unaided by any device other than corrective lenses. This continuous observation serves four purposes: knowing the aircraft's relative position and bearing, determining its attitude, altitude, and heading, observing the airspace for other air traffic and hazards, and confirming the aircraft does not endanger life or property.

Throughout the flight, this capability must be exercised by either (1) the remote pilot in command together with the person manipulating the flight controls, or (2) a designated visual observer.

Exceptions & edge cases

Permitted aid: Prescription eyeglasses and contact lenses (corrective lenses) are the only visual aids allowed under Part 107.

Prohibited aids: Binoculars, night vision devices, and any other visual enhancement aids are explicitly prohibited for maintaining visual line of sight.

Alternative observer: When a visual observer is used, at least one qualified individual must maintain continuous visual line of sight with the aircraft at all times during operation.