Lesson 4.3 – Flight Rules (Part 91 Highlights)

Part 91 of the Federal Aviation Regulations contains the general operating and flight rules that apply to most general aviation flying. This lesson covers the key rules every Private Pilot must know.

Reference:

14 CFR Part 91 – General Operating and Flight Rules

Pilot in Command Responsibility

91.3 – The pilot in command is directly responsible for, and is the final authority as to, the operation of the aircraft. In an emergency, the PIC may deviate from any rule in Part 91 to the extent necessary to meet that emergency.

Preflight Action

91.103 – Before beginning a flight, the pilot in command must become familiar with all available information concerning that flight. This includes weather, fuel requirements, alternates, runway lengths, and aircraft performance.

Right-of-Way Rules

91.113 – When weather conditions permit, pilots must maintain vigilance to see and avoid other aircraft.

Right-of-way priority (in simplified order):

Aircraft in distress
Balloons
Gliders
Airships
Powered parachutes / weight-shift control
Airplanes and rotorcraft

When two aircraft are approaching head-on, both should alter course to the right.

The aircraft on the right has the right-of-way when converging at approximately the same altitude.

Minimum Safe Altitudes

91.119

Anywhere: An altitude allowing an emergency landing without undue hazard to people or property on the surface.
Over congested areas: 1,000 feet above the highest obstacle within a 2,000-foot horizontal radius.
Over other than congested areas: 500 feet above the surface (except over open water or sparsely populated areas, where you must remain at least 500 feet from any person, vessel, vehicle, or structure).

Speed Limits

91.117

Maximum 250 knots indicated airspeed below 10,000 feet MSL.
Maximum 200 knots indicated airspeed in airspace underlying Class B or in a VFR corridor through Class B.
Maximum 200 knots indicated airspeed at or below 2,500 feet AGL within 4 nautical miles of the primary airport of Class C or Class D airspace (unless otherwise authorized or required).

Fuel Requirements (VFR)

91.151

Day VFR: Enough fuel to fly to the first point of intended landing and then for at least 30 minutes.
Night VFR: Enough fuel to fly to the first point of intended landing and then for at least 45 minutes.

Key Points to Remember

The pilot in command is the final authority and is responsible for the safe operation of the flight.
Preflight action under 91.103 is mandatory.
Know the right-of-way rules and minimum safe altitudes.
Always meet or exceed the VFR fuel requirements.
Speed limits exist below 10,000 feet and near certain controlled airports.

Basic VFR Weather Minimums – 14 CFR 91.155

Class B

• Visibility: 3 statute miles

• Cloud clearance: Clear of clouds

Class C

• Visibility: 3 statute miles

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class D

• Visibility: 3 statute miles

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class E (less than 10,000 ft MSL)

• Visibility: 3 statute miles

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class E (at or above 10,000 ft MSL)

• Visibility: 5 statute miles

• Cloud clearance: 1,000 ft below, 1,000 ft above, 1 statute mile horizontal

Class G (1,200 ft or less above the surface – Day)

• Visibility: 1 statute mile

• Cloud clearance: Clear of clouds

Class G (1,200 ft or less above the surface – Night)

• Visibility: 3 statute miles

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class G (more than 1,200 ft above the surface but less than 10,000 ft MSL – Day)

• Visibility: 1 statute mile

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class G (more than 1,200 ft above the surface but less than 10,000 ft MSL – Night)

• Visibility: 3 statute miles

• Cloud clearance: 500 ft below, 1,000 ft above, 2,000 ft horizontal

Class G (more than 1,200 ft above the surface and at or above 10,000 ft MSL)

• Visibility: 5 statute miles

• Cloud clearance: 1,000 ft below, 1,000 ft above, 1 statute mile horizontal

Main Notes & Exceptions

1. Special VFR (14 CFR 91.157)

This is the biggest exception. With an ATC clearance, you may operate in Class B, C, D, or E surface areas with lower minimums:

1 statute mile flight visibility
Clear of clouds

Night Special VFR requires an instrument rating and an IFR-equipped aircraft. Some busy airports prohibit Special VFR.

2. Ceiling Requirement in Controlled Airspace (91.155(c))

You may not operate under VFR beneath the ceiling within the lateral boundaries of controlled airspace designated to the surface for an airport when the ceiling is less than 1,000 feet (unless you have a Special VFR clearance).

3. Takeoff / Landing / Traffic Pattern Rule (91.155(d))

You may not take off, land, or enter the traffic pattern of an airport under VFR within the surface area of Class B, C, D, or E airspace when the ground visibility is less than 3 statute miles (again, Special VFR is the exception).

4. Helicopters

Helicopters have slightly different (usually lower) minimums in certain Class G airspace, but this is not required knowledge for most Private Pilot airplane students.

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