---
title: "What are the maximum altitude and speed limits for small unmanned aircraft operations under 14 CFR 107.51? Answer in under 100 words."
canonical: https://www.m-i-n-d.ai/minds/drones/maximum-altitude-speed-limits-small-unmanned-aircraft-operations-under-14-cfr
jurisdiction: "US Federal · FAA · 14 CFR Part 107"
last_verified: 2026-08-26
license: CC BY 4.0 — https://creativecommons.org/licenses/by/4.0/
attribution: "Source: MIND (m-i-n-d.ai)"
---

# What are the maximum altitude and speed limits for small unmanned aircraft operations under 14 CFR 107.51? Answer in under 100 words.

Under 14 CFR 107.51, the maximum groundspeed for a small unmanned aircraft is 87 knots (100 miles per hour), and the maximum altitude is 400 feet above ground level. The only stated exception allows flight within a 400-foot radius of a structure, up to but not exceeding 400 feet above the structure's immediate uppermost limit.

## Details / How it works

Section 107.51 imposes operating limitations on both the **remote pilot in command** and the **person manipulating the flight controls** of a small unmanned aircraft system. These limits are mandatory whenever the small unmanned aircraft system is operated.

## Numbers & thresholds

| Limit | Value |
|---|---|
| Maximum groundspeed | 87 knots (100 miles per hour) |
| Maximum altitude | 400 feet above ground level (AGL) |

Minimum flight visibility is also set at 3 statute miles from the control station, with cloud clearances of 500 feet below and 2,000 feet horizontally.

## Exceptions & edge cases

The 400-foot altitude ceiling does not apply when the aircraft:

- Is flown **within a 400-foot radius of a structure**; and
- Does **not fly higher than 400 feet above the structure's immediate uppermost limit**.

No other exceptions to the speed or altitude limits are provided in § 107.51.

## Sources

- [1] U.S. National Archives, Electronic Code of Federal Regulations — 14 CFR 107.51 — Operating limitations for small unmanned aircraft · https://www.ecfr.gov/current/title-14/section-107.51 · as of 2026-08-26