Definitions You Must Know: sUAS, UA, Control Station and More
Every other regulation in Part 107 is built on top of a small set of precisely defined terms in 14 CFR 107.3. Getting these definitions exactly right matters more than it might seem ? test questions frequently hinge on the precise legal meaning of a word like "unmanned aircraft" versus "small unmanned aircraft system," and misreading the distinction is one of the most common sources of missed points on ACS Area I. This lesson works through every core definition in plain English first, then in the regulation's own words.
Unmanned aircraft (UA)
In plain English: an unmanned aircraft is just the airframe itself ? the physical flying object ? with no person on board able to directly control it from inside or on top of it. The regulation defines it precisely as "an aircraft operated without the possibility of direct human intervention from within or on the aircraft." Notice this definition says nothing about size or weight ? it is purely about the absence of an onboard human operator. A small quadcopter and a large military drone are both "unmanned aircraft" under this definition; the size distinction comes in with the next term.
Small unmanned aircraft
This term adds the weight limit that makes Part 107 applicable at all: a small unmanned aircraft is an unmanned aircraft weighing less than 55 pounds on takeoff, including everything on board or attached to it ? the battery, camera, gimbal, and any payload count toward that weight. This is the aircraft category virtually every consumer and commercial drone falls into, and it's the reason Lesson A of Module 1 explained that drones 55 pounds or heavier fall outside the standard Part 107 framework entirely.
Small unmanned aircraft system (small UAS / sUAS)
This is the broadest of the core terms, and the one that gives the whole regulation its name. An sUAS is not just the aircraft ? it is the small unmanned aircraft together with every associated element needed to operate it safely, including the communication link between the aircraft and the person on the ground, and the components that control the aircraft. When people informally say "drone," they usually mean the sUAS as a whole system, not just the airframe.
Control station
The control station is simply the interface the remote pilot uses to control the aircraft's flight path ? most commonly a handheld transmitter/controller, sometimes paired with a tablet or smartphone running a flight-control app. The regulation's definition is deliberately technology-neutral, since control station hardware varies widely across manufacturers and continues to evolve.
Visual observer
A visual observer is a person the remote pilot in command specifically designates to help watch the sky and ground for other aircraft, people, or obstacles ? helping the flight crew "see and avoid" hazards. This role, and the specific duties that come with it, are covered in full in Lesson F of this module; the definition itself simply establishes who counts as a visual observer for regulatory purposes.
Real-world scenario: why the distinctions matter
A film production company owns a 6-pound camera drone. The physical airframe alone is the "unmanned aircraft." Because it weighs under 55 pounds, it also qualifies as a "small unmanned aircraft." Once you add the handheld controller, the video downlink, and the tablet running the flight app, the whole assembly is the "small unmanned aircraft system" that Part 107 actually regulates. During a shoot, the pilot designates a production assistant to watch for approaching helicopters ? that assistant is now, in the regulation's precise terms, a "visual observer," with the specific communication and coordination duties covered in Lesson F.
How 14 CFR 107.3's core terms nest inside one another, from the bare airframe to the full operating system.
View Larger| Term | Plain-English meaning | Key distinguishing feature | Regulation |
|---|---|---|---|
| Unmanned aircraft (UA) | The airframe alone, no onboard pilot | No weight limit in this definition | 14 CFR 107.3 |
| Small unmanned aircraft | An unmanned aircraft under 55 lb at takeoff | Includes everything on board/attached | 14 CFR 107.3 |
| Small UAS (sUAS) | The aircraft plus control link and controlling components | Broadest term ? the whole system | 14 CFR 107.3 |
| Control station | The interface used to control flight path | Technology-neutral definition | 14 CFR 107.3 |
| Visual observer | A person designated to help see and avoid hazards | Must be specifically designated by the remote PIC | 14 CFR 107.3 |
| Mistake | Why it happens | Correct understanding | Regulation / source |
|---|---|---|---|
| "Unmanned aircraft and sUAS mean the same thing." | Both terms are used loosely as synonyms for "drone" in everyday speech | Unmanned aircraft is the airframe alone; sUAS is the aircraft plus the control link and controlling components as a full system. | 14 CFR 107.3 |
| "The 55-pound weight limit applies to the term 'unmanned aircraft.'" | Conflating the general and weight-limited definitions | The 55-pound ceiling is specific to "small unmanned aircraft," not the broader "unmanned aircraft" definition. | 14 CFR 107.3 |
| "Anyone standing nearby watching the drone is automatically a visual observer." | Assuming the role is informal | A visual observer must be specifically designated by the remote pilot in command, with defined duties under 107.33. | 14 CFR 107.3; 107.33 |
Is a smartphone running a flight app considered part of the "control station"?
Yes, if it is part of the interface used to control the aircraft's flight path ? the definition is intentionally technology-neutral and covers whatever hardware/software combination the remote pilot actually uses to fly.
Does the 55-pound weight limit include the battery and camera?
Yes. The "small unmanned aircraft" definition explicitly includes everything on board or attached to the aircraft at takeoff, not just the bare airframe weight.
Can the remote pilot in command also serve as their own visual observer?
The definitions in 107.3 establish the visual observer as a distinct designated role; 107.31 (Lesson E) clarifies that the required "see and avoid" capability can be satisfied either by the remote pilot in command and person manipulating the controls together, or by a visual observer, so the roles work together rather than requiring three separate people on every flight.
Test Your Knowledge
Answer the questions below to check your understanding. Every answer can be found in the lesson above.