FAR 91.117 — Aircraft Speed Limits
FAR 91.117 sets aircraft speed limits below 10,000 ft MSL, near Class C/D airports, and under Class B airspace. Study guide for pilot students and checkrides.
FAR 91.117 establishes the maximum indicated airspeeds you must observe in different chunks of airspace. Knowing these cold matters because busting a speed limit is an easy way to get a phone number from ATC — and it's a common checkride question.
The limits are:
- Below 10,000 feet MSL: no faster than 250 knots indicated, unless the Administrator authorizes otherwise.
- At or below 2,500 feet AGL within 4 NM of the primary Class C or Class D airport: no faster than 200 knots indicated. This does not apply inside Class B — there you follow the 250-knot rule below 10,000 MSL.
- Underneath a Class B shelf or in a VFR corridor through Class B: no faster than 200 knots indicated.
If the minimum safe airspeed for your operation (think heavy jets, certain configurations) is higher than the limit, you may fly that minimum safe speed instead. This is a safety exception, not a free pass to go fast.
Five FAA-written-style questions. Instant explanations, every answer cites its source — no account needed.
You are flying VFR in Class E airspace at 8,500 feet MSL during the day. What are your minimum visibility and cloud clearance requirements?
Q1What is the maximum indicated airspeed below 10,000 feet MSL?
Q2What speed restriction applies when flying beneath a Class B shelf or through a VFR corridor?
Q3If your aircraft's minimum safe airspeed is higher than the speed limit in the regulation, what are you allowed to do?
Aircraft speed limits by airspace
Below 10,000 feet MSL the maximum indicated airspeed is 250 knots (288 mph) under 14 CFR § 91.117(a); at or below 2,500 feet AGL within 4 nautical miles of a Class C or Class D primary airport, and in the airspace under a Class B shelf or a VFR corridor, the cap drops to 200 knots (230 mph) (verified 2026-07-02). Every limit in this section is an indicated airspeed, so it does not change with altitude even though your true airspeed does.
What 14 CFR § 91.117 actually limits
| Citation | Where it applies | Max indicated airspeed | Key condition |
|---|---|---|---|
| § 91.117(a) | Below 10,000 ft MSL (anywhere) | 250 kt (288 mph) | Unless otherwise authorized by the Administrator. |
| § 91.117(b) | At or below 2,500 ft AGL, within 4 NM of a Class C or Class D primary airport | 200 kt (230 mph) | Unless authorized or required by ATC. Does not apply inside Class B — there, only the § 91.117(a) 250-kt rule applies. |
| § 91.117(c) | Airspace underlying a Class B area, or a VFR corridor through Class B | 200 kt (230 mph) | Applies to everyone — there is no ATC waiver for this cap. |
| § 91.117(d) | Any operation whose minimum safe airspeed is greater than the cap | Minimum safe airspeed | The speed rule yields when a higher speed is required for safe operation. |
| Speed cap | Equivalent (mph) | Ground covered per minute |
|---|---|---|
| 250 kt | 288 mph | 4.2 NM/min |
| 200 kt | 230 mph | 3.3 NM/min |
The 200-knot Class C/D cap in § 91.117(b) applies only at or below 2,500 ft AGL and within 4 NM of the primary airport — and it does not apply inside Class B. Under a Class B shelf, though, § 91.117(c) still caps you at 200 knots with no ATC waiver.
Most training aircraft never reach these caps, so § 91.117 is often a knowledge-test and oral-exam topic rather than a hands-on limit. At 250 knots you close 4.2 NM every minute — the reason the limit tightens to 200 knots in the congested airspace around primary airports.
Aircraft speed limit FAQ
What is the speed limit below 10,000 feet MSL?
Under 14 CFR § 91.117(a), no person may operate an aircraft below 10,000 feet MSL at an indicated airspeed of more than 250 knots (288 mph), unless otherwise authorized by the Administrator.
What is the maximum speed near a Class C or Class D airport?
Section 91.117(b) caps indicated airspeed at 200 knots (230 mph) at or below 2,500 feet above the surface within 4 nautical miles of the primary airport of a Class C or Class D airspace area, unless authorized or required by ATC.
Is there a speed limit under a Class B shelf or in a VFR corridor?
Yes. Section 91.117(c) limits indicated airspeed to 200 knots (230 mph) in the airspace underlying a Class B area and in any VFR corridor designated through Class B. Unlike the § 91.117(b) rule, there is no ATC waiver for this cap.
Is there a 200-knot speed limit inside Class B airspace?
No. Section 91.117(b) explicitly states its 200-knot cap does not apply to operations within a Class B airspace area — inside Class B you comply with § 91.117(a), the 250-knot limit below 10,000 feet MSL. The 200-knot cap applies under Class B, not inside it.
What if my minimum safe airspeed is higher than the § 91.117 limit?
Under 14 CFR § 91.117(d): if the minimum safe airspeed for a particular operation is greater than the maximum speed prescribed in this section, the aircraft may be operated at that minimum safe airspeed.