How to File an IFR Flight Plan
Since 2019 the FAA requires ICAO-format flight plans for all IFR domestic flights in the US. This guide walks through filing via ForeFlight (most common), the field-by-field meaning, and the FAR 91.169 requirements for fuel and alternates.
Prerequisites
- → Instrument-rated pilot
- → Current ICAO equipment / surveillance codes for your aircraft
- → Departure, route, destination, and alternate planned
- → ForeFlight, Garmin Pilot, FltPlan.com, or 1800wxbrief account
Step-by-Step
- 1
Plan the route
Use departure SID, en-route airways or direct, and destination STAR. Save the cleared route from previous flights. ATC may issue 'cleared as filed' if route is sensible.
- 2
Determine fuel requirements (FAR 91.167)
Fuel to destination + fuel to alternate (if required) + 45 minutes reserve at normal cruise. If destination ceiling/vis is forecast 600 ft and 2 SM at ETA +/- 1 hour, no alternate needed (1-2-3 rule).
- 3
Choose alternate airport(s) (when required)
FAR 91.169(c) requires alternate if forecast at destination is below 1,000-2,000 ft / 1-3 SM. Alternate must have suitable approach minimums.
- 4
Open ForeFlight FPL form
Enter origin, destination, alternate, route, ETD.
- 5
Set aircraft equipment / surveillance codes
Item 10a (equipment) and 10b (surveillance). Most modern GA: SDFGY (Standard, DME, GNSS, FMC, Mode S+ADS-B). Verify in your aircraft specs.
- 6
Set TAS and altitude
Item 15. Cruise TAS in knots. Cruise altitude (FL or thousands) appropriate for direction (East = odd, West = even).
- 7
Add remarks
Item 18. PBN/ codes for RNAV capabilities. DOF/ for date. EET/ for special. ALTN/ for alternate field.
- 8
File 30+ minutes before ETD
Click File. Plan auto-routes through Lockheed Martin to FAA NAS. Check filed status before departure.
Common Mistakes
- × Wrong equipment codes — most common cause of flight plan rejection
- × Forgetting alternate when 1-2-3 rule triggers it
- × Filing 5 minutes before departure — not enough time for routing
- × Routing through SUA without checking activation
Pro Tips
- ★ Save common routes as 'favorites' in ForeFlight for one-tap filing
- ★ If you forecast holds, file extra fuel — ATC will reroute happier with a full tank
- ★ Check NOTAMs in the same flow — ForeFlight shows them in flight plan summary
- ★ Brief the SID/STAR before takeoff even if you've flown it before
Conclusion
Modern ForeFlight or Garmin Pilot makes IFR filing nearly one-click for routine flights. The skill that matters is understanding what each ICAO field means so you can troubleshoot rejections from ATC. Master the equipment codes for your aircraft once and filing becomes mechanical.
FAQ
Do I need to file an IFR plan in VFR weather?
If you want IFR services and altitude (Class A, RVSM), yes. Otherwise VFR with flight following is sufficient under FAR 91 in CAVOK.
What is PBN?
Performance-Based Navigation — codes like RNAV1, RNAV5, RNP4 indicating your aircraft's nav specs. Required in Item 18 for all modern IFR.