FAR 91.169 sets the IFR flight plan requirements in two parts: the plan must contain the standard information listed in 14 CFR 91.153(a), and it must name an alternate airport unless your destination has a published instrument approach and the forecast weather from one hour before to one hour after your ETA shows at least a 2,000-foot ceiling and 3 statute miles visibility.1eCFR. 14 CFR 91.169 – IFR Flight Plan: Information Required Everything else in the regulation is detail on those two points.
Information the Plan Must Contain
91.169(a) pulls in the baseline items from 91.153(a). Those are your aircraft identification, aircraft type, the pilot-in-command’s name and address, departure point and time, proposed route and cruising altitude, destination, fuel on board expressed in hours, and the number of persons on board.2eCFR. 14 CFR 91.153 – VFR Flight Plan: Information Required You also include radio frequencies and any other information ATC considers necessary. On top of the 91.153 list, 91.169 adds the alternate airport when one is required.
Fuel endurance and persons on board are the two numbers worth double-checking. Search-and-rescue coordinators rely on them directly. A fuel figure that is off by an hour points a search into the wrong area; a wrong headcount changes the urgency of the response.
ICAO Format and Equipment Codes
The FAA requires the ICAO flight plan format for nearly all flights in the National Airspace System, with limited exceptions for Department of Defense plans and civilian stereo route plans. The ICAO format is also required for any flight departing U.S. domestic airspace and any flight requesting performance-based navigation routing.3Federal Aviation Administration. FAA Flight Planning Information
The change from the old domestic form lives mostly in Item 10, where you list navigation and surveillance equipment by letter code. “S” covers the standard set of VOR, VHF, and ILS. “G” indicates GNSS. Transponder and ADS-B equipment goes in Item 10b using codes such as “B1” for 1090 MHz ADS-B out or “U1” for UAT out. Most electronic filing apps populate these codes from your aircraft profile, but the codes still need to match your installed and operational equipment.
When an Alternate Airport Is Required
Pilots call this the 1-2-3 rule. You do not need to list an alternate only when both of the following are true: your destination has a published instrument approach procedure, and the forecast shows a ceiling of at least 2,000 feet above the airport elevation and visibility of at least 3 statute miles for the full period from one hour before to one hour after your estimated arrival.1eCFR. 14 CFR 91.169 – IFR Flight Plan: Information Required If either condition fails, you file an alternate.
Two situations trip pilots up. First, if your destination has no published instrument approach at all, you always need an alternate no matter what the weather is doing. Second, the forecast must cover the entire arrival window. If the TAF only covers part of the hour-before-to-hour-after span, the gap counts against you and an alternate is required.
Weather Minimums the Alternate Must Meet
Once an alternate is required, the airport you pick has to meet its own weather test at your estimated time of arrival there:1eCFR. 14 CFR 91.169 – IFR Flight Plan: Information Required
- Precision approach available (ILS or comparable): ceiling at least 600 feet, visibility at least 2 statute miles.
- Non-precision approach available (VOR, NDB, LNAV, or similar): ceiling at least 800 feet, visibility at least 2 statute miles.
- No instrument approach at all: weather must allow descent from the minimum IFR altitude to a landing under basic VFR conditions.
Those are standard alternate minimums. Many airports carry non-standard minimums, marked on the approach chart by the letter “A” inside a dark inverted triangle. When you see that symbol, look up the specific values in the Terminal Procedures Publication before filing. “A NA” beside the triangle means the airport cannot be used as an alternate at all, typically because it lacks a monitored weather observation or has unmonitored navigation facilities.4Federal Aviation Administration. IFR Alternate Minimums
GPS and WAAS Limits on Picking an Alternate
Modern avionics create a planning trap here. When you file, your alternate must have an available instrument approach that does not rely on GPS, unless your aircraft is equipped with WAAS (TSO-C145 or TSO-C146).5Aeronautical Information Manual. Area Navigation (RNAV) and Required Navigation Performance (RNP) The restriction also reaches flights planning to use GPS as a substitute for an out-of-service VOR that underlies an approach at the alternate.
WAAS aircraft are exempt because WAAS carries its own integrity monitoring. With a basic non-WAAS GPS (TSO-C129 or TSO-C196), you can plan a GPS-based approach at your destination or at your alternate, but not both. If the destination approach you are counting on is GPS, the alternate needs a conventional approach you are equipped to fly. WAAS-equipped pilots can file GPS approaches at both airports.
Fuel Reserves Tied to the Alternate
Fuel planning under 14 CFR 91.167 tracks the alternate decision directly. You must carry enough fuel to fly to the destination, then from the destination to the alternate, then 45 additional minutes at normal cruise. Helicopters get a 30-minute reserve instead of 45.6eCFR. 14 CFR 91.167 – Fuel Requirements for Flight in IFR Conditions
When no alternate is required under the 1-2-3 rule, the fuel requirement drops to destination plus 45 minutes. Note the linkage: the exception that lets you skip the alternate is the same exception that lets you plan less fuel. If the forecast sits close to 2,000 and 3, carrying fuel for an alternate anyway is the safer call.
Closing the Plan After Landing
At a towered airport, ATC closes your IFR flight plan automatically on landing.7Federal Aviation Administration. Aeronautical Information Publication – Flight Planning At a non-towered airport, you close the plan yourself, either by radio before losing ATC contact or by phone after landing. If a plan sits open for 30 minutes past your ETA, Flight Service starts an information check that can escalate to a full search-and-rescue response.8Federal Aviation Administration. Search and Rescue Build the closing call into a post-landing checklist if you regularly fly into non-towered fields.
Penalties
Filing an inaccurate IFR flight plan, operating without a required alternate, or missing the fuel reserve can all draw FAA enforcement. Under 49 U.S.C. 46301, the statutory maximum civil penalty for an individual pilot is $1,100 per violation before inflation adjustments.9Office of the Law Revision Counsel. 49 USC 46301 – Civil Penalties The FAA also uses certificate action, including suspension or revocation, which for most pilots outweighs the money.