Part 91 Series — Right-of-Way, Speed Limits & Minimum Altitudes: The “Rules of the Road” in the Sky
Driving has traffic laws.
Boating has navigation rules.
And aviation?
Aviation has Part 91.
Once you’re airborne in a small aircraft — whether it’s a Cessna practicing touch-and-goes or a Piper cruising cross-country — you’re sharing the sky with other airplanes, helicopters, gliders, balloons, and sometimes even parachutists.
That’s why Part 91 includes very specific “rules of the road” that govern:
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Who has the right-of-way
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How fast you’re allowed to fly
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How low you’re allowed to descend
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When you must comply with ATC instructions
These aren’t just checkride talking points. They’re practical, real-world regulations that apply on every flight.
In this fifth installment of our 8-part Part 91 series, we’ll break down the operational rules that keep traffic flowing safely in the National Airspace System — especially for small-aircraft pilots.
Let’s look outside and see who yields.
The Core “Rules of the Road” Regulations
In this article, we’re covering:
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§91.111 — Operating near other aircraft
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§91.113 — Right-of-way rules
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§91.117 — Aircraft speed
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§91.119 — Minimum safe altitudes
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§91.123 — Compliance with ATC clearances and instructions
Together, these regulations define how pilots must operate around others and within the system.
§91.111 — Operating Near Other Aircraft
No person may operate an aircraft so close to another aircraft as to create a collision hazard.
Formation flight is allowed — but only by prior arrangement with the pilots involved.
For typical small-aircraft operations, this simply reinforces a key principle:
See and avoid.
Even in controlled airspace, collision avoidance remains the pilot’s responsibility.
§91.113 — Right-of-Way Rules
This is the heart of in-flight traffic priority.
Some key highlights:
Aircraft in Distress
An aircraft in distress has right-of-way over all other air traffic.
Converging Aircraft (Same Category)
When two aircraft of the same category converge at approximately the same altitude (except head-on), the aircraft to the right has the right-of-way.
If you see another airplane approaching from your right — you yield.
Head-On Approaches
Both aircraft alter course to the right.
Overtaking
The aircraft being overtaken has the right-of-way.
The overtaking aircraft must alter course to the right.
Different Categories
Priority generally goes in this order:
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Balloons
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Gliders
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Airships
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Powered aircraft
A powered airplane must yield to a glider.
Landing Aircraft
Aircraft on final approach or landing have right-of-way over aircraft in flight or operating on the surface.
However, you cannot cut in front of someone already established on final.
These rules are especially important at non-towered airports.
§91.117 — Speed Limits
Part 91 establishes maximum speed limits in certain areas.
Below 10,000 feet MSL:
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250 knots indicated airspeed (KIAS) maximum.
Within 4 nautical miles of Class C or D primary airports:
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200 KIAS maximum at or below 2,500 feet AGL.
For most small piston aircraft, these limits are well above normal cruise speeds — but they still matter, especially for high-performance aircraft.
ATC may authorize higher speeds in certain cases.
§91.119 — Minimum Safe Altitudes
This regulation protects people and property on the ground.
Except for takeoff and landing:
Over Congested Areas:
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At least 1,000 feet above the highest obstacle within a 2,000-foot horizontal radius.
Over Other Than Congested Areas:
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At least 500 feet above the surface.
Over Open Water or Sparsely Populated Areas:
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At least 500 feet from any person, vessel, vehicle, or structure.
The rule ensures safety margins for engine failures and reduces risk to people below.
§91.123 — Compliance with ATC Clearances
When operating under an ATC clearance, you must comply with that clearance unless:
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You obtain an amended clearance,
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An emergency exists, or
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The clearance would result in a collision hazard.
If you deviate due to an emergency, ATC may request a written report.
Even VFR pilots in controlled airspace must follow ATC instructions once communication is established.
At this level, you understand the baseline operational rules.
But practical application often raises deeper questions.
