Definition
The Federal Aviation Regulation (Title 14 of the Code of Federal Regulations, Part 91, Section 103) titled 'Preflight Action,' which requires the pilot in command, before any flight, to become familiar with all available information concerning that flight. For flights not in the vicinity of an airport, and for any IFR flight, this specifically includes weather reports and forecasts, fuel requirements, alternatives available if the planned flight cannot be completed, and any known traffic delays advised by ATC. It also requires knowledge of runway lengths at airports of intended use and the aircraft's takeoff and landing distance data.
Plain English
This is the rule that says before you fly, you must check the weather, plan your fuel, know your alternates, and confirm the runways are long enough for your aircraft. It is the legal basis for preflight planning.
Context Anchor
Seen in preflight planning, weather briefing, flight planning, and FAA discussions of what a pilot must check before departure.
Derivation
The '§' symbol means 'section' and comes from the Latin 'signum sectionis' (sign of section). '91.103' identifies the regulation as Part 91, Section 103 of Title 14 CFR. Knowing the symbol helps pilots read regulatory citations quickly.
Why Pilots Care
Ensures pilots have the information needed to make safe go/no-go decisions and avoid regulatory violations.
Intuition Check
Do not read § 91.103 as a weather rule only. It is the broad preflight action rule: the pilot must be familiar with all available information needed for the flight.
Example Sentence 1
Before the cross-country flight, the pilot reviewed weather, fuel requirements, and runway lengths to satisfy § 91.103.
Example Sentence 2
§ 91.103 requires identifying a suitable alternate airport when the destination forecast shows marginal conditions.