What are the basic operating limitations under Part 107 for small UAS?

Under 14 CFR Part 107, small unmanned aircraft must be flown at or below 400 feet above ground level in uncontrolled airspace, during daylight or civil twilight (with anti-collision lighting), and within visual line of sight of the remote pilot in command or a visual observer. The aircraft must remain clear of manned aircraft at all times, and operations over moving vehicles or people are generally prohibited without a waiver. These limitations are designed to integrate small UAS safely into the National Airspace System alongside manned aviation.

Who is responsible for the safe operation of a small UAS under Part 107, and what does that responsibility include?

The Remote Pilot in Command (Remote PIC) bears full and final responsibility for the safe operation of the small UAS under 14 CFR Part 107.19, similar to the responsibility a pilot in command holds for a manned aircraft under 14 CFR Part 91. This responsibility includes conducting a preflight assessment of the operating area, ensuring the aircraft is in safe operating condition, and making go/no-go decisions based on weather, airspace, and other risk factors. The Remote PIC must also comply with all applicable regulations and may not delegate this authority to a visual observer or other crew member.

What is the difference between a Part 107 waiver and a Part 107 airspace authorization?

A Part 107 waiver allows a Remote PIC to operate outside one or more of the standard operating limitations—such as flying at night, beyond visual line of sight, or over people—after demonstrating to the FAA that the proposed operation can be conducted safely. An airspace authorization, obtained through the FAA's LAANC system or DroneZone portal, grants permission to fly in controlled airspace (Class B, C, D, or surface Class E) where operations are otherwise prohibited without prior approval under 14 CFR Part 107.41. The two approvals address different regulatory requirements: waivers modify operational rules, while airspace authorizations address where you may fly.

Part 107 Operating Limitations and Responsibility of Remote PIC

When Congress directed the FAA to integrate unmanned aircraft systems (UAS) into the National Airspace System, the agency responded with Title 14 CFR Part 107—the regulatory framework that governs small UAS (sUAS) operations for non-recreational purposes. At the heart of Part 107 is a carefully balanced set of operating limitations designed to keep unmanned aircraft predictable, visible, and safely separated from manned aviation. Equally important is the concept of the Remote Pilot in Command (Remote PIC), who bears the same legal and safety accountability for an sUAS flight that a certificated pilot bears for a manned aircraft. Whether you are studying for the FAA Unmanned Aircraft General knowledge test or getting ready to fly commercially, mastering these limitations and responsibilities is non-negotiable.

This article walks through the specific operating limitations codified in 14 CFR §107.51 and surrounding sections, explains the Remote PIC's authority and duties under §107.19, and highlights the practical, real-world implications of each rule. The FAA's Pilot's Handbook of Aeronautical Knowledge and the dedicated FAA study materials for Part 107 ground every concept discussed here.

Core Operating Limitations Under Part 107

Part 107 establishes a set of default operating limitations. These limitations apply to all standard Part 107 operations unless a waiver has been granted by the FAA under §107.200. Think of them as the baseline envelope within which all legal sUAS commercial or non-recreational flight must occur.

Altitude

A small UAS may not be flown higher than 400 feet above ground level (AGL) under standard rules. This ceiling exists primarily to keep sUAS well below the altitudes routinely used by low-flying manned aircraft such as agricultural planes and helicopters. There is one important exception: when the drone is flown within a 400-foot lateral radius of a structure, it may fly up to 400 feet above the structure's immediate uppermost limit. This means that if you are inspecting a 300-foot communications tower, you could legally ascend to 700 feet AGL in the immediate vicinity of the structure, since the 400-foot bubble extends upward from the top of the tower itself. This is a heavily tested nuance on the FAA knowledge exam.

Airspeed

The maximum groundspeed for a Part 107 sUAS is 100 mph (87 knots). This limit helps ensure that a remote pilot can maintain adequate situational awareness and that the aircraft remains controllable within the see-and-avoid framework.

Daylight and Civil Twilight Operations

Standard Part 107 operations are limited to daylight and civil twilight—defined as the 30 minutes before official sunrise and the 30 minutes after official sunset. During civil twilight operations, the sUAS must be equipped with anti-collision lighting visible for at least 3 statute miles. This lighting requirement exists because ambient light is reduced, and the drone must remain conspicuous to other aircraft and the remote pilot. Operations in full darkness require an FAA waiver.

Visual Line of Sight (VLOS)

The Remote PIC (or a designated visual observer) must maintain visual line of sight with the sUAS at all times. This means unaided vision—or standard eyeglasses or contact lenses—not binoculars, cameras, first-person-view (FPV) goggles alone, or other vision-enhancing devices. The requirement ensures that the remote pilot can immediately assess the aircraft's attitude, altitude, and position relative to terrain, people, and other air traffic. A visual observer (VO) may assist with VLOS, but the Remote PIC retains full responsibility and must be able to take over direct situational awareness at any time.

Airspace

Operations in Class B, C, D airspace, and within the lateral boundaries of a surface area of Class E airspace designated for an airport require prior authorization from the controlling ATC facility. The FAA's Low Altitude Authorization and Notification Capability (LAANC) system allows remote pilots to obtain automated airspace authorization for many locations instantly. Class G airspace (uncontrolled) does not require ATC authorization, though pilots must still comply with all other Part 107 rules. Operating in prohibited or restricted areas requires appropriate authorization from the controlling or using agency, just as with manned aircraft.

People, Moving Vehicles, and Moving Watercraft

A Part 107 sUAS may not be operated over moving vehicles, moving watercraft, or any person not directly involved in the operation unless the operation is conducted over a controlled or restricted-access site and anyone within the area has been informed that an sUAS may fly overhead. This limitation protects uninvolved persons from the risk of a falling drone. A waiver can authorize flight over people if the operator demonstrates adequate safety mitigations.

One Aircraft at a Time

A single Remote PIC may operate only one sUAS at a time. This limitation reflects the cognitive demands of maintaining situational awareness; simultaneously piloting multiple aircraft would fragment attention in ways the FAA considers unsafe without special authorization.

Carriage of Hazardous Materials

Part 107 prohibits the transport of hazardous materials that would pose a risk to the aircraft or people on the ground. The FAA considers cargo risk as part of the broader safety equation for any sUAS flight.

The Remote Pilot in Command: Authority and Responsibility

The Remote PIC is the person who has final authority over and responsibility for the operation of an sUAS. Under 14 CFR §107.19, the Remote PIC:

Is directly responsible for and is the final authority on the operation of the sUAS.
Must ensure the sUAS is in a safe condition to operate before each flight.
Must ensure that the operation poses no undue hazard to people, property, or other aircraft.
Must comply with all applicable Part 107 regulations.

Separately, under 14 CFR §107.37, the small UAS must yield the right-of-way to all other aircraft, manned or unmanned. This right-of-way duty operates as a see-and-avoid rule for the sUAS operation—the remote pilot must give way to manned aircraft rather than expecting the manned aircraft to maneuver around the sUAS.

The Remote PIC must hold a valid Remote Pilot Certificate with an sUAS rating (or be under direct supervision of someone who does during training). The certificate must be made available to the FAA upon request. Recurrent knowledge testing is required every 24 calendar months to maintain currency.

Pre-Flight Responsibilities

Before every flight, the Remote PIC must conduct a thorough pre-flight inspection of the sUAS. This includes inspecting the aircraft, control station, launch and landing areas, and any object that will be attached to or carried by the aircraft. The Remote PIC must also assess the operational environment: weather conditions, airspace classification, potential hazards to people on the ground, and the location of other aircraft. If any condition would render the operation unsafe, the Remote PIC has not only the authority but the obligation to cancel or delay the flight.

The Remote PIC also bears responsibility for ensuring that any visual observer (VO) on the operation understands their duties, maintains communication with the Remote PIC, and is positioned to effectively watch the aircraft. The VO does not need a Remote Pilot Certificate but must be briefed and coordinated by the Remote PIC before flight begins.

Why These Limitations Matter

Each limitation in Part 107 exists because of a real, quantifiable safety concern. The 400-foot AGL ceiling aligns with where manned aircraft commonly transition altitudes near airports and in low-altitude operations. The VLOS requirement ensures the remote pilot can apply a see-and-avoid principle analogous to what manned pilots use under Visual Flight Rules. Restricting operations over uninvolved people limits the consequences of a mechanical failure or pilot error. And placing full responsibility on the Remote PIC creates a clear, legally accountable chain of command—eliminating ambiguity about who is in charge when something goes wrong.

The FAA's foundational safety philosophy is that accountability and authority must be co-located. Because the Remote PIC has the authority to end a flight at any moment, they also bear the full weight of any accident or violation. This mirrors the Pilot in Command (PIC) concept under 14 CFR §91.3 for manned aircraft.

Key Numbers and Rules

400 ft AGL — maximum altitude (or 400 ft above a structure within a 400-ft lateral radius).
100 mph (87 knots) — maximum groundspeed.
Civil twilight — 30 min before sunrise / 30 min after sunset; requires 3-statute-mile visible anti-collision lighting.
1 aircraft at a time — single Remote PIC, single sUAS.
VLOS required — unaided vision; FPV goggles alone do not satisfy VLOS.
24 calendar months — recurrent knowledge test interval for Remote PIC currency.
Right-of-way (§107.37) — sUAS must yield to all other aircraft, manned or unmanned.
ATC authorization required for Class B, C, D, and surface E airspace; LAANC is the primary tool for obtaining it.

Memory Aid

A useful memory device for the core Part 107 limitations is АВА—Altitude, Visibility (VLOS), Airspace. Before every flight, ask yourself: Am I within altitude limits? Can I see my aircraft? Do I have airspace authorization? If all three answers are yes, you have cleared the three most frequently tested and most commonly violated pillars of Part 107 operating limitations. From there, layer in speed, daylight, people, and cargo considerations to complete your pre-flight regulatory review.

Common Test Traps

The structure exception trap: Many students forget that the 400-foot AGL ceiling can extend higher near structures. If the question describes a tall tower, the legal ceiling is 400 feet above the top of the tower, not 400 feet above the ground at its base.
Civil twilight vs. night: The FAA distinguishes civil twilight (waiver-free with proper lighting) from full darkness (requires a waiver). Don't confuse the two, and remember the lighting must be visible for 3 statute miles—not just present on the aircraft.
FPV goggles and VLOS: A question may describe a pilot flying exclusively through FPV goggles without a visual observer. This violates VLOS requirements. A VO must maintain unaided visual contact if the pilot is using goggles.
Who is the Remote PIC: The test may describe a scenario where a certificated remote pilot is supervising a trainee. The certificated pilot remains the Remote PIC and retains full legal responsibility for the operation, even if the trainee is manipulating the controls.
24-calendar-month currency: Students sometimes confuse this with the 24-month recency-of-experience rules for manned aircraft (like passenger-carrying). The Remote PIC's recurrent knowledge test is about certification currency—if the test lapses, the certificate is no longer valid for exercising Remote PIC privileges.