UA.I.B.K10: Visual line of sight (VLOS) aircraft operations.

ACS Area I — Regulations Task B: Operating Rules References: 14 CFRCode of Federal RegulationsCloseThe federal rulebook where Part 107, Part 89, Part 48, and other aviation rules live. parts 47, 48, 89, and 107, subpart B; ACAdvisory CircularCloseFAA guidance that explains acceptable ways to comply with rules or understand FAA procedures. 107-2; FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-H-8083-25; FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-G-8082-22

Key Concepts

Why VLOS Matters: Visual Judgment and Separation

Visual line of sight (VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight.) is the foundation for see-and-avoid decision-making. In visual operations, pilots—not automation—resolve conflicts. Manned-aviation procedures illustrate the standard: controllers provide separation services except when visual separation is being applied by the pilot, and accepting instructions to visually follow another aircraft makes the pilot responsible to maneuver and maintain safe in-trail spacing until flight paths diverge. This underscores the core of VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight.—continuous visual awareness to avoid other aircraft and hazards.^[6] Weather also matters in visual operations: visual approaches require a reported ceiling at or above 1,000 feet and visibility of 3 miles or greater; when vectoring to a visual approach, the ceiling must be at least 500 feet above the minimum vectoring altitude (MVA) with 3 miles visibility. These minima reflect the visibility needed to see, judge closure, and act—exactly the competencies VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. enables.^[6]

Line-of-Sight in Busy Airspace: Traffic, Parallel Runways, and Wake

Near towered airports, multiple aircraft can be on simultaneous visual approaches. Examples include parallel runways separated by less than 2,500 feet (with tighter sequencing and pilot sighting requirements) and operations where controllers use a 30-degree intercept to reduce overshoots; when separation is 4,300 feet or more, simultaneous visual operations may be authorized after advisory. These figures reinforce that many aircraft may be visually maneuvering at once—strong justification for maintaining robust VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. and airspace scanning whenever operating nearby.^[5]

Wake turbulence further highlights why uninterrupted visual observation is critical. Controllers apply specific minimum radar separations behind heavier aircraft because vortices persist and drift: for instance, small/large behind heavy is 5 miles; heavy behind super is 6 miles; small behind super is 8 miles; and small behind a B757 is 4 miles. Visual techniques also emphasize maintaining a sightline above and ahead of a heavier aircraft’s flightpath and landing beyond its touchdown point, with “no less than 1,000 feet from the arrival end” as a reference point. Even if you are not landing on a runway, these practices translate into VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. habits: keep the aircraft and potential hazards in view, maintain vertical and lateral buffers, and avoid flight paths where hazards (including wake) may exist.^[8]

VLOS Around People and Vehicles: Risk Categories and Practical Limits

VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. becomes even more critical when flight paths intersect people or vehicles. Under operations over moving vehicles, if the site is not closed- or restricted-access, only transit is permitted—no sustained flight—over people not directly participating (applies to Category 1–3). Category 4 aircraft may be eligible if not prohibited by FAAFederal Aviation AdministrationCloseThe U.S. aviation regulator responsible for Part 107 rules, airspace, and pilot certification processes.-approved limitations. Within closed/restricted sites, not-directly-participating persons must at least be on notice. Category 1 aircraft weigh 0.55 pounds (250 grams) or less; Category 2 aircraft must meet design requirements, including not exceeding 11 foot-pounds of kinetic energy on impact, having no exposed rotating parts that would lacerate skin, and having no safety defects. Labels and operating instructions are required for Category 2 eligibility. All of these constraints assume you can continuously see your aircraft to avoid sustained exposure over people and to keep clear of moving vehicles—exactly what effective VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. enables in practice.^[3][2]

Preflight discipline supports safe VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. operations. Part 107 requires a preflight inspection and ensuring the aircraft is in a condition for safe operation; for operations over people, the remote PICRemote Pilot in CommandCloseThe certificated remote pilot responsible for the Part 107 operation. should elevate the preflight assessment, considering where people are, weather, and other risk factors. Sound VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight. practice begins with anticipating how visibility, crowds, and environment could degrade your ability to see, orient, and avoid.^[7]

Operating Legally: Registration and Documentation

Before any operation, ensure the aircraft is properly registered. For non-recreational use, a Certificate of Aircraft Registration under § 48.100 constitutes registration for the specific small unmanned aircraft. Registration is effective on the date shown on the certificate and expires 3 years after the date of issue unless renewed. Renewal requires verifying or updating information within the six months preceding the month of expiration. Keeping registration current is part of professional operating discipline that complements VLOSVisual Line of SightCloseThe requirement to see the drone well enough to know its location, attitude, altitude, and direction of flight.-focused risk management.^[1]