Flight Planning Reference
ICAO flight plan form, equipment codes, NOTAMs, fuel planning, alternates, route formats, pre-flight briefing, and winds aloft.
Last reviewed: March 2026
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ICAO Flight Plan Form
The ICAO flight plan (ICAO Doc 4444) is the internationally standardised format for filing flight plans. Each numbered field (item) contains specific information required by ATC and search and rescue services. The most operationally significant items are listed below.
| Item | Field | Content |
|---|---|---|
| 7 | Aircraft ID | Aircraft registration (e.g., G-ABCD) or callsign. Used by ATC for identification on radar and for search and rescue coordination. |
| 8 | Flight Rules / Type | Flight rules: V (VFR), I (IFR), Y (IFR then VFR), Z (VFR then IFR). Type of flight: G (general aviation), S (scheduled), N (non-scheduled), M (military), X (other). |
| 9 | Aircraft / Wake Turbulence | ICAO aircraft type designator (e.g., C172, B738) followed by wake turbulence category: L (Light, MTOW ≤7,000 kg), M (Medium, 7,000–136,000 kg), H (Heavy, >136,000 kg), J (Super — A380). |
| 10 | Equipment | COM/NAV equipment and surveillance codes. Slash-separated list. See Equipment Codes section. Example: SDE2E3FGHIJ/LB1. |
| 13 | Departure | ICAO 4-letter aerodrome identifier (e.g., EGLL) and EOBT (Estimated Off-Blocks Time) in UTC, format HHMM. |
| 15 | Route | Cruise speed and level, followed by route. Format: N0250F085 HELEN DCT TRENT. Speed in knots (N) or Mach (M); level in Flight Level (F) or altitude (A). |
| 16 | Destination / EET / Alternate | ICAO destination identifier, total estimated elapsed time (HHMM), alternate aerodrome(s). |
| 18 | Other Information | Supplementary information including PBN capabilities, NAV details, departure time if different from field 13, EET for FIR boundaries, RMK (remarks). |
| 19 | Supplementary | Fuel endurance (HHMM), persons on board (TBE or number), emergency equipment (R for radio, S for survival), pilot name and contact for SAR coordination. |
Equipment Codes
Field 10 of the ICAO flight plan contains codes describing the aircraft's communication, navigation, and surveillance equipment. These are critical for ATC to provide appropriate services and for flight plan processing systems.
COM/NAV Equipment Codes
| Code | Equipment |
|---|---|
| S | Standard — VHF RTF, VOR, ILS (the minimum for IFR in most states) |
| H | HF RTF |
| U | UHF RTF |
| V | VHF RTF |
| C | LORAN C |
| D | DME |
| F | ADF |
| G | GNSS (GPS or other GNSS) |
| J | Data link (CPDLC, ADS, ACARS) |
| K | MLS |
| L | ILS |
| M | Omega |
| O | VOR |
| R | PBN approved (must include PBN/ in field 18) |
| T | TACAN |
| W | RVSM approved |
| X | MNPS approved |
| Y | VHF with 8.33 kHz channel spacing capability |
| N | No COM/NAV equipment — or not equipped with any equipment for the route to be flown |
Surveillance Equipment Codes (after the slash /)
| Code | Surveillance Equipment |
|---|---|
| N | No surveillance equipment |
| A | Transponder Mode A (4096 codes) only |
| C | Transponder Mode A and Mode C |
| E | Transponder Mode S, including aircraft ID, pressure altitude and extended squitter (ADS-B) |
| H | Transponder Mode S, aircraft ID and altitude — including enhanced surveillance |
| I | Transponder Mode S, aircraft ID only — no altitude |
| L | Transponder Mode S, aircraft ID, altitude, extended squitter and enhanced surveillance |
| S | Transponder Mode S, aircraft ID and altitude transmission |
| P | Transponder Mode S, pressure altitude, no aircraft ID |
| B1 | ADS-B with dedicated 1090 MHz ADS-B “out” capability |
NOTAM Types
NOTAMs (Notices to Air Missions / Airmen) are official notices containing information essential to flight safety. They are issued in a standardised ICAO format and must be checked as part of every pre-flight briefing.
| Type | Description |
|---|---|
| NOTAM N (New) | A new NOTAM establishing new information. Published on the AIRAC cycle for pre-planned changes, or immediately (trigger NOTAM) for unplanned events. |
| NOTAM R (Replace) | Replaces a previous NOTAM in its entirety. The replaced NOTAM number is cited in the text. |
| NOTAM C (Cancel) | Cancels a specific NOTAM. The cancelled NOTAM number is cited. After a NOTAM C, the original information is no longer in effect. |
NOTAM Format Structure
Each NOTAM follows a standard format with labeled fields:
- Series/Number/Year: e.g., A1234/26 — NOTAM series A, number 1234, year 2026
- Q line: Contains the NOTAM code in 5 parts: FIR/subject/condition/traffic/purpose/scope/lower/upper/coordinates-radius. Used for automated NOTAM selection and NOTAM filtering systems.
- A line: Location — ICAO aerodrome identifier or FIR identifier
- B line: Start of validity — date/time in YYMMDDHHMM UTC format
- C line: End of validity (or PERM for permanent)
- D line: Schedule (if not continuous) — active times within the validity period
- E line: Full text of the NOTAM — the actual operational information
- F/G lines: Lower and upper limits of affected airspace (if applicable)
NOTAM Q-Code Subject Codes (selected)
| Subject Code | Subject Area | Example |
|---|---|---|
| MX | Taxiway(s) | Taxiway closed |
| MR | Runway | Runway surface condition |
| IC | ILS (combined) | ILS unserviceable |
| LV | VOR | VOR unserviceable or reduced power |
| LN | NDB | NDB off-air |
| AT | Aerodrome — Tower ATC | Control tower hours change |
| RA | Airspace — Restricted Area | Temporary restricted area activated |
| WA | Aerodrome warnings | Works in progress, cranes |
| XX | Plain language | Free text for items not covered by standard codes |
Fuel Planning
Fuel planning must account for all contingencies and meet regulatory minimum reserves. The EASA fuel planning hierarchy for VFR flights consists of the following components, calculated in sequence:
| Fuel Component | Description |
|---|---|
| Taxi fuel | Allowance for engine start, warm-up, and taxi to holding point. Typically 10–15 minutes at ground idle power. Check aircraft performance manual for specific values. |
| Trip fuel | Fuel required from take-off to destination — including the climb, cruise, descent, and approach phases. Calculated from performance charts using planned route, altitude, temperature, and wind. |
| Contingency fuel | Minimum 5% of trip fuel under EASA rules. Accounts for unforeseen circumstances: weather deviations, ATC route changes, winds stronger than forecast, slightly degraded performance. |
| Alternate fuel | Fuel to fly from destination to nominated alternate aerodrome (where an alternate is required). Calculated on the same basis as trip fuel for that segment. |
| Final reserve | 30 minutes at normal cruise consumption for VFR day. 45 minutes for VFR night. This reserve must never be used — it is the absolute minimum on landing. If it would be used, declare minimum fuel. |
| Additional fuel | Commander's discretion — any additional margin beyond the above. May be added for remote areas, unreliable weather, destination without alternate, or low confidence in forecast winds. |
EASA / UK CAA minimum fuel reserve: 30 minutes at normal cruise consumption for VFR day. 45 minutes for night VFR. This final reserve must never be planned to be used — it is the absolute minimum on landing. Plan with additional contingency fuel on top of the calculated minimum.
Alternate Aerodrome Selection
An alternate aerodrome must be nominated in the flight plan when destination conditions may be below minima at the estimated time of arrival. Selection criteria vary between VFR and IFR operations.
| Approach Type | Alternate Aerodrome Minima |
|---|---|
| CAT I ILS or better | Ceiling: 200 ft above the ILS decision height. Visibility: 800 m above the ILS RVR minima. (Typically: ceiling 400 ft, visibility 1500 m minimum.) |
| Non-Precision Approach (NPA) | Ceiling: 200 ft above the MDA. Visibility: 1000 m above the approach minima. |
| Circling approach | Ceiling: 200 ft above circling MDA. Visibility: circling visibility minima + 1500 m. |
Note: These are minimum weather requirements for designation as an alternate — the alternate must meet these criteria at the estimated time of arrival. Actual conditions at the alternate must be above the applicable approach minima to permit a landing there.
Route Formats
Field 15 of the ICAO flight plan contains the cruise speed, cruising level, and route. The format is standardised to allow automated processing by ATC systems worldwide.
Pre-Flight Briefing
A thorough pre-flight weather and NOTAM briefing is both a legal requirement and a fundamental safety practice. The following 12-item checklist covers the essential elements of a complete pre-flight briefing for IFR and complex VFR operations:
- Obtain latest METAR for departure, destination, and alternates
- Check TAF for destination — valid to cover ETA ±1 hour
- Review SIGMETs and AIRMETs for the route and altitude band
- Check winds aloft for planned cruise altitude (see Winds Aloft section)
- Review any relevant PIREPs for icing, turbulence, or cloud tops
- Obtain NOTAM briefing for departure, en-route, destination, and alternate aerodromes
- Check TFRs / Temporary Restricted Areas along the route
- Verify navaid serviceability (VOR, ILS, NDB) via D-series NOTAMs
- Calculate fuel: trip fuel + contingency + alternate (if required) + final reserve
- Verify mass and balance — both at departure weight and estimated landing weight
- Check aircraft performance — take-off and landing distances for conditions
- File flight plan (if required) with accurate EOBT and alternate
Regulatory note: Failure to obtain an adequate pre-flight weather briefing is a leading cause of VFR-into-IMC accidents. Do not rely on memory of previous briefings — obtain a fresh briefing within 2–3 hours of departure. For IFR operations, re-brief if departure is delayed by more than 1 hour.
Winds Aloft
Winds aloft forecasts (Forecast Upper Wind, FU, or WINTEM charts) are issued by meteorological authorities at standard altitudes and are essential for accurate fuel planning, flight time estimation, and route selection at cruise altitude. The ICAO format for winds aloft encodes wind direction, speed, and temperature at a given altitude.
| Digits | Meaning | Example |
|---|---|---|
| 1–2 | Wind direction in tens of degrees true (00–36) | 27 = 270°T |
| 3–4 | Wind speed in knots (or km/h if so designated) | 35 = 35 kt |
| 5–6 | Temperature in degrees Celsius (negative preceded by minus sign) | -18 = minus 18°C |