Under 14 CFR 91.103, the pilot in command must become familiar with all available information concerning a flight before leaving the ground. The regulation splits that duty into two tiers: a short list that applies to every flight, and a longer list that adds on once the flight goes under instrument flight rules or leaves the vicinity of an airport. Preflight action under 14 CFR 91.103 is the legal floor for what you have to know before you release the brakes, and “I didn’t check” is not a defense once something goes wrong.
The Two Tiers of the Rule
Paragraph (b) applies to any flight, from pattern work at your home field to a cross-country. You must check the runway lengths at each airport you plan to use and review takeoff and landing distance data for your aircraft. If the airplane has an FAA-approved flight manual or pilot’s operating handbook with performance charts, you’re required to use them. For older aircraft without an approved manual, the rule calls for “other reliable information” covering airport elevation, runway slope, gross weight, wind, and temperature.
Paragraph (a) adds four items when you’re flying IFR or leaving the vicinity of an airport: weather reports and forecasts, fuel requirements, alternatives if the planned destination becomes unavailable, and any traffic delays ATC has communicated to you. A quick pattern flight at a local uncontrolled field in clear weather doesn’t legally require a full briefing. Anything beyond that local bubble does.
The phrase “not in the vicinity of an airport” isn’t defined with a mileage number. The FAA expects pilots to use judgment, and that gray area means erring on the side of a full briefing is the safer legal position.
Runway Length and Aircraft Performance
This is the one requirement that applies to every flight, regardless of weather or distance. You must know the runway lengths at each airport you plan to use and confirm your aircraft can safely operate within those distances.
Runway lengths and airport data are published in the FAA’s Chart Supplement (formerly the Airport/Facility Directory), available digitally through the FAA’s aeronautical products page. Relying on memory or outdated data is one of the easiest ways to end up with the pavement running out before the airplane is ready to fly.
The pilot’s operating handbook contains manufacturer charts that account for airport elevation, temperature, aircraft weight, wind, and runway slope. Plug in the actual conditions and you get the expected takeoff roll, the takeoff distance to clear a 50-foot obstacle, and the landing distance. High elevation and hot temperatures are the classic combination that catches pilots off guard, because together they dramatically increase the runway needed to get airborne.
For aircraft without an approved flight manual, the regulation still requires “other reliable information” covering these variables. That might mean type-club performance data, manufacturer’s information sheets, or documented test results. You can’t skip the calculation because your airplane is old enough not to have a formal POH.
Weight, Balance, and Density Altitude
91.103 doesn’t spell out “weight and balance” as a separate checklist item, but the reference to “aircraft gross weight” in paragraph (b)(2) and the broader “all available information” language make it inseparable from performance planning. An airplane loaded beyond its maximum gross weight or outside its center of gravity envelope won’t perform anything like the numbers in the handbook.
The center of gravity shifts during flight as fuel burns off and cargo settles, so the calculation needs to account for both takeoff and landing conditions. The FAA’s Pilot’s Handbook of Aeronautical Knowledge notes that less-dense air reduces engine power, propeller efficiency, and wing lift at the same time. Density altitude captures those effects in a single number that tells you how the airplane feels the air, regardless of what the altimeter reads.
Weather Briefings and Self-Briefing
Calling Flight Service is still the traditional route. The 1-800-WX-BRIEF line reaches a specialist, and the Leidos Flight Service site at 1800wxbrief.com hosts weather products online. Flight Service Stations remain the FAA’s designated primary source for preflight weather briefings.
What’s changed is that the FAA now formally recognizes self-briefing. Advisory Circular 91-92 states that a self-briefing using online automated weather resources can comply with federal aviation regulations, provided the pilot conducts a thorough evaluation of weather and aeronautical information before the flight. The AC identifies the products to review, including METARs, TAFs, SIGMETs, AIRMETs, convective SIGMETs, and center weather advisories.
AC 91-92 also flags a limitation worth remembering: cockpit weather tools like FIS-B don’t carry every product or NOTAM that a full preflight briefing covers, and NEXRAD radar mosaics displayed in the cockpit can be 15 to 20 minutes old by the time they reach the screen. These tools supplement preflight preparation. They don’t replace it.
Fuel Requirements
91.103 says you must review “fuel requirements,” but the actual reserve minimums live in two separate rules depending on how you’re flying.
VFR Reserves
Under 14 CFR 91.151, you cannot begin a VFR flight in an airplane unless you carry enough fuel to reach your first landing point and then continue flying for at least 30 minutes during the day or 45 minutes at night, both calculated at normal cruising speed. These are hard minimums.
IFR Reserves
IFR planning under 14 CFR 91.167 is more demanding. You need enough fuel to fly to your destination, then from your destination to your filed alternate airport, and then fly for an additional 45 minutes at normal cruising speed. The alternate leg can be dropped only when the destination has a published instrument approach and the weather is forecast to be at least a 2,000-foot ceiling and 3 statute miles visibility for one hour before and after your estimated arrival.
Experienced pilots plan well beyond these numbers. The regulation sets the floor. Running the numbers before departure and confirming them against actual conditions is exactly what 91.103 demands.
NOTAMs, TFRs, and Traffic Delays
Notices to Air Missions cover closed runways, inoperative navigation aids, unlit towers, construction cranes, and temporary flight restrictions, and they change constantly. The FAA’s NOTAM Search tool at notams.aim.faa.gov is the primary digital portal, and NOTAMs are included in any Flight Service briefing.
Temporary Flight Restrictions deserve extra attention. TFRs appear around presidential movements, wildfire operations, sporting events, and security-sensitive areas, and flying into an active one can escalate well beyond a paperwork problem.
Traffic delays round out the paragraph (a) requirements. The FAA’s National Airspace System Status page at nasstatus.faa.gov shows real-time ground stops and delay programs at major airports. That matters most for IFR flights into busy terminal areas where a ground stop could leave you holding with fuel burning down, and even VFR pilots benefit from knowing which airports are under flow control before committing to a route.
Using an Electronic Flight Bag to Comply
Most pilots now do their preflight planning on tablets that integrate weather, NOTAMs, performance calculators, and charts on one platform. The FAA addressed this in Advisory Circular 91-78A, which provides guidance for replacing paper charts and documentation with electronic flight bag applications. The AC makes clear that EFBs are an acceptable means of meeting regulatory requirements, but operators who use them must follow the guidance “in all important respects.”
Using an app like ForeFlight or Garmin Pilot satisfies 91.103 as long as you’re actually reviewing the information rather than just having the app installed. The regulation requires you to become familiar with the information, not just have access to it. A tablet in your flight bag with weather data you never looked at doesn’t count.
What Happens If You Skip It
The FAA treats 91.103 violations seriously because they often surface as contributing factors after accidents or incidents. Enforcement actions fall into two categories: certificate actions and civil penalties.
Certificate suspensions run for a fixed number of days to discipline the pilot and deter similar conduct. The FAA doesn’t publish a standard suspension schedule for 91.103 violations because the duration depends on the severity of the lapse and any resulting consequences. More serious cases, or those combined with other violations, can lead to certificate revocation, where the FAA determines the pilot is no longer qualified to hold a certificate at all.
Civil penalties for individuals who are not acting as airmen can reach $17,062 per violation, with a cap of $100,000 per enforcement action. Penalties for certificate holders acting as airmen follow a separate schedule. The FAA’s enforcement process typically begins with an informal conference that gives the pilot an opportunity to present mitigating evidence.
Most enforcement actions don’t start with a random audit. They start after something goes wrong and the investigation reveals that the pilot didn’t check the weather, didn’t run performance numbers, or didn’t review NOTAMs. At that point 91.103 is the regulation that makes the entire chain of errors legally actionable.