2.3 General Operating & Flight Rules (14 CFR Part 91)

General Operating & Flight Rules (14 CFR Part 91)

14 CFR Part 91 serves as the operating umbrella for all civil aviation operations within the United States. Ground instructors must possess a rigorous mastery of these rules to train pilots in emergency decision-making, flight planning, airspace speed compliance, equipment airworthiness, and required maintenance inspections.

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Pilot in Command Authority & Preflight Action (14 CFR 91.3 & 91.103)

Pilot in Command Responsibility and Emergency Authority (14 CFR 91.3)

Under 14 CFR 91.3(a), the Pilot in Command (PIC) of an aircraft is directly responsible for, and is the final authority as to, the operation of that aircraft. This fundamental principle underpins all aviation safety.

In an in-flight emergency requiring immediate action, 14 CFR 91.3(b) grants the PIC extraordinary authority: the pilot may deviate from any rule of Part 91 to the extent required to meet that emergency. A pilot who deviates from a regulation during an emergency is not required to submit a written report to the FAA automatically; under 14 CFR 91.3(c), a written report must be submitted only upon the request of the Administrator.

Mandatory Preflight Action: The NWKRAFT Rule (14 CFR 91.103)

Under 14 CFR 91.103, each pilot in command shall, before beginning a flight, become familiar with all available information concerning that flight. The regulation creates a two-tiered mandate:

1. For Any Flight (Including Local Airport Pattern Work):
   • Runway lengths at airports of intended use.
   • Takeoff and landing distance data under expected temperatures, field elevations, aircraft gross weight, and wind conditions.
2. For Flights under IFR or Flights Not in the Vicinity of an Airport:
   • N: NOTAMs (Notices to Air Missions).
   • W: Weather reports and forecasts.
   • K: Known ATC traffic delays.
   • R: Runway lengths at airports of intended use.
   • A: Alternates available if the planned flight cannot be completed.
   • F: Fuel requirements (VFR day/night reserves).
   • T: Takeoff and landing performance data.

The regulation itself lists weather reports and forecasts, fuel requirements, alternatives, and known ATC traffic delays for IFR flights and flights away from the airport vicinity; NOTAMs fall under the general duty to become familiar with all available information.

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Right-of-Way Rules (14 CFR 91.113)

When weather conditions permit, regardless of whether a flight is conducted under IFR or VFR, vigilance shall be maintained by each person operating an aircraft so as to see and avoid other aircraft. When aircraft collide or converge, right-of-way rules dictate priority:

1. In Distress

An aircraft in distress has the right-of-way over all other air traffic.

2. Converging Aircraft

When aircraft of the same category are converging at approximately the same altitude (except head-on), the aircraft to the other's right has the right-of-way.

When aircraft of different categories are converging, the following hierarchy of priority applies:

1. Balloons (highest priority—least maneuverable).
2. Gliders.
3. Airships.
4. Powered Parachutes / Weight-Shift-Control / Airplanes / Rotorcraft.

Special Category Rule: An aircraft towing or refueling another aircraft has right-of-way over all other engine-driven aircraft.

3. Head-On Approach

When aircraft are approaching each other head-on, or nearly so, each pilot shall alter course to the right.

4. Overtaking Aircraft

An aircraft that is being overtaken has the right-of-way. The overtaking aircraft shall alter course to the right to pass well clear.

5. Landing

Aircraft on final approach to land, or while landing, have the right-of-way over other aircraft in flight or on the surface. When two or more aircraft are approaching an airport for the purpose of landing, the aircraft at the lower altitude has the right-of-way, but a pilot shall not take advantage of this rule to cut in front of another aircraft or overtake it.

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Airspeed Limits & Minimum Safe Altitudes (14 CFR 91.117 & 91.119)

Airspeed Limitations (14 CFR 91.117)

Safety Relief: If the minimum safe airspeed for any particular operation (e.g., heavy transport aircraft maneuver margin) is greater than the prescribed maximum speed, the aircraft may be operated at that minimum safe speed.

Minimum Safe Altitudes (14 CFR 91.119)

Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes:

• Anywhere: An altitude allowing, if a power unit fails, an emergency landing without undue hazard to persons or property on the surface.
• Over Congested Areas: Over any congested area of a city, town, or settlement, or over any open-air assembly of persons, an altitude of 1,000 feet above the highest obstacle within a horizontal radius of 2,000 feet of the aircraft.
• Over Other Than Congested Areas: An altitude of 500 feet above the surface, except over open water or sparsely populated areas. In those areas, the aircraft may not be operated closer than 500 feet to any person, vessel, vehicle, or structure.

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VFR Fuel Requirements & Cruising Altitudes

VFR Fuel Reserves (14 CFR 91.151)

No person may begin a flight in an airplane under VFR conditions unless, considering wind and forecast weather conditions, there is enough fuel to fly to the first point of intended landing and, assuming normal cruising fuel consumption:

• Day VFR: Fly for at least 30 minutes beyond destination.
• Night VFR: Fly for at least 45 minutes beyond destination.

VFR Cruising Altitudes (14 CFR 91.159)

When operating VFR in level cruising flight more than 3,000 feet above the surface and below 18,000 feet MSL, aircraft must maintain altitudes based on magnetic course (91.159):

• Magnetic Course 000° through 179° ("East is Odd"): Odd thousands plus 500 feet (e.g., 3,500, 5,500, 7,500 ft MSL).
• Magnetic Course 180° through 359° ("West is Even + 500"): Even thousands plus 500 feet (e.g., 4,500, 6,500, 8,500 ft MSL).

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Required Instruments & Inoperative Equipment (14 CFR 91.205 & 91.213)

Required Equipment for VFR Flight (14 CFR 91.205)

Day VFR (ATOMATOFLAMES):

• A: Airspeed indicator
• T: Tachometer for each engine
• O: Oil pressure gauge for each engine
• M: Manifold pressure gauge for each altitude engine
• A: Altimeter
• T: Temperature gauge for each liquid-cooled engine
• O: Oil temperature gauge for each air-cooled engine
• F: Fuel gauge indicating quantity in each tank
• L: Landing gear position indicator (for retractable gear)
• A: Anti-collision light system (aviation red or white, required for small civil airplanes certificated after March 11, 1996)
• M: Magnetic direction indicator (compass)
• E: Emergency locator transmitter (ELT, under 91.207)
• S: Safety belts, plus shoulder harnesses for front seats of small civil airplanes manufactured after July 18, 1978

For flights for hire over water beyond power-off gliding distance from shore, approved flotation gear and at least one pyrotechnic signaling device are also required.

Night VFR (FLAPS - Added to Day Requirements):

• F: Fuses (spare set, or three spare fuses of each kind required, accessible to pilot)
• L: Landing light (if aircraft is operated for hire)
• A: Anti-collision light system
• P: Position lights (navigation lights: red left, green right, white tail)
• S: Source of electrical energy (alternator/generator)

Inoperative Equipment Process (14 CFR 91.213(d))

If an aircraft lacks an approved Minimum Equipment List (MEL), inoperative equipment may be deferred only if it is not:

1. Part of the VFR-day type certification requirements.
2. Listed as required on the aircraft's Kind of Operations Equipment List (KOEL).
3. Required by 14 CFR 91.205, 91.207, or other Part 91 operational rules.
4. Required to be operative by an Airworthiness Directive (AD).

If the item is not required, it must be deactivated and placarded "Inoperative" (or removed, cockpit control placarded, and weight/balance recalculated) before flight.

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Aircraft Airworthiness Inspections (14 CFR Part 91 Subpart E)

Civil aircraft operating under Part 91 must undergo strict periodic maintenance inspections summarized by the mnemonic AVIATES:

The 100-Hour Overflight Allowance

Under 14 CFR 91.409(b), the 100-hour limitation may be exceeded by not more than 10 hours exclusively while en route to an inspection facility where the 100-hour inspection can be performed. The excess hours flown must be deducted from the next 100-hour inspection interval. For example, if an inspection due at 100 hours is accomplished at 108 hours, the next inspection is due 92 hours later, at 200 hours.