Drone speed, altitude, visibility and cloud limits14 CFR 107.51 Operating limitations for small unmanned aircraft
A small unmanned aircraft may not exceed a groundspeed of 87 knots (100 miles per hour) or fly higher than 400 feet above ground level, except near a structure. Flight visibility from the control station must be at least 3 statute miles, and the aircraft must stay at least 500 feet below and 2,000 feet horizontally from clouds.
By the ATIS Alerts team · Updated October 15, 2026 · Regulation text current as of October 14, 2026. A study aid based on the official regulation text, not legal advice or an FAA interpretation.
At a glance
- Groundspeed: no more than 87 knots (100 miles per hour) (a).
- Altitude: no higher than 400 feet above ground level (b).
- Structure exception: within a 400-foot radius of a structure, no higher than 400 feet above the structure's immediate uppermost limit (b)(1) and (b)(2).
- Visibility: at least 3 statute miles flight visibility, as observed from the location of the control station (c).
- Clouds: at least 500 feet below and 2,000 feet horizontally (d).
- Both the remote pilot in command and the person manipulating the flight controls must comply (opening text).
In plain English
Section 107.51 sets the basic operating limits, and both the remote pilot in command and the person manipulating the flight controls must comply with all of them. The speed limit is a groundspeed of 87 knots (100 miles per hour) (a). Because it is groundspeed, a tailwind counts toward it.
The altitude limit is 400 feet above ground level (b), with one exception. A small unmanned aircraft flown within a 400-foot radius of a structure may go higher, as long as it does not fly higher than 400 feet above the structure's immediate uppermost limit. Both conditions, (b)(1) and (b)(2), have to be met.
The weather limits are measured from the control station. Flight visibility, as observed from the location of the control station, must be at least 3 statute miles, and the rule defines flight visibility as the average slant distance from the control station at which prominent unlighted objects may be seen and identified by day and prominent lighted objects by night (c). The aircraft must also stay at least 500 feet below clouds and 2,000 feet horizontally from them (d).
Common mistakes
- Confusing groundspeed with airspeed. The 87-knot (100 miles per hour) limit is groundspeed (a).
- Reading the structure exception as unlimited height near buildings. The aircraft must stay within a 400-foot radius of the structure and no higher than 400 feet above its immediate uppermost limit (b).
- Adding the 1,000-foot above-cloud distance from 91.155. Section 107.51(d) lists 500 feet below and 2,000 feet horizontally.
- Measuring visibility from the aircraft. The 3 statute miles is observed from the location of the control station (c).
The official text
14 CFR 107.51 as published on the eCFR, current as of October 14, 2026.
A remote pilot in command and the person manipulating the flight controls of the small unmanned aircraft system must comply with all of the following operating limitations when operating a small unmanned aircraft system:
(a) The groundspeed of the small unmanned aircraft may not exceed 87 knots (100 miles per hour).
(b) The altitude of the small unmanned aircraft cannot be higher than 400 feet above ground level, unless the small unmanned aircraft:
(1) Is flown within a 400-foot radius of a structure; and
(2) Does not fly higher than 400 feet above the structure's immediate uppermost limit.
(c) The minimum flight visibility, as observed from the location of the control station must be no less than 3 statute miles. For purposes of this section, flight visibility means the average slant distance from the control station at which prominent unlighted objects may be seen and identified by day and prominent lighted objects may be seen and identified by night.
(d) The minimum distance of the small unmanned aircraft from clouds must be no less than:
(1) 500 feet below the cloud; and
(2) 2,000 feet horizontally from the cloud.
Test yourself
Practice questions from our free FAA written test prep that cite 14 CFR 107.51.
Part 107 Drone
What is the maximum allowable groundspeed of a small unmanned aircraft under part 107?
- A. 87 knots (100 mph).
- B. 100 knots.
- C. 45 knots.
- D. 55 knots (63 mph).
Show answer
A. 87 knots (100 mph). 87 knots, which is 100 miles per hour. Note that it is a GROUNDSPEED limit, so a strong tailwind can push a drone past it even when its airspeed is well within limits.
More Part 107 Drone practice →Part 107 Drone
A remote pilot is inspecting a 1,500-foot tower. What is the maximum altitude at which the small unmanned aircraft may operate?
- A. 1,900 feet AGL, because it may fly within 400 feet of the structure.
- B. 400 feet AGL, with no exception for structures.
- C. 1,500 feet AGL, matching the height of the structure.
- D. 500 feet AGL.
Show answer
A. 1,900 feet AGL, because it may fly within 400 feet of the structure. The 400-foot AGL ceiling has one exception: within a 400-foot radius of a structure, the aircraft may fly up to 400 feet ABOVE the structure's uppermost limit. A 1,500-foot tower therefore allows 1,900 feet AGL, but only while staying within 400 feet laterally of it.
More Part 107 Drone practice →Part 107 Drone
What are the minimum flight visibility and cloud clearance requirements for part 107 operations?
- A. 3 statute miles visibility from the control station; 500 feet below and 2,000 feet horizontally from clouds.
- B. 3 statute miles visibility; 500 feet below, 1,000 feet above, 2,000 feet horizontally.
- C. 1 statute mile visibility and clear of clouds.
- D. 5 statute miles visibility; 1,000 feet below and 1 statute mile horizontally.
Show answer
A. 3 statute miles visibility from the control station; 500 feet below and 2,000 feet horizontally from clouds. Three statute miles of flight visibility measured FROM THE CONTROL STATION, and the aircraft must stay 500 feet below and 2,000 feet horizontally from any cloud. There is no "above" figure. A drone is not expected to be above the clouds.
More Part 107 Drone practice →
Questions pilots ask
What is the maximum altitude for a drone under Part 107?
400 feet above ground level (107.51(b)). The exception: within a 400-foot radius of a structure, the aircraft may fly up to 400 feet above the structure's immediate uppermost limit (107.51(b)(1) and (b)(2)).
How fast can a drone fly under Part 107?
The groundspeed may not exceed 87 knots (100 miles per hour) (107.51(a)).
What are the Part 107 visibility and cloud clearance requirements?
At least 3 statute miles flight visibility as observed from the location of the control station (107.51(c)), and at least 500 feet below and 2,000 feet horizontally from clouds (107.51(d)).