# Flight plan
**A flight plan specifies how a flight is planned to be conducted.** Along with the callsign and aircraft type, it also includes the planned route, altitude, and speed. This ensures that both the pilot and the controller are on the same page with the flight's planning.
Flights under Instrument Flight Rules (IFR) are always required to file a flight plan, whereas flights under Visual Flight Rules (VFR) have the option to do so.
On VATSIM, it is important to note that once a flight plan has been edited by a controller, the pilot can no longer modify it themselves!
### Flight plan format
The format of flight plans is identical worldwide and prescribed by ICAO. It’s possible that a flight plan may not appear in the classic input fields but instead in the following format. This format includes all the key information that air traffic control needs to know from the pilot:
```
(FPL-DLH5YK-IS
-A320/M-SDE3FGHIRWY/LB1
-EDDF1220
-N0444F230 CINDY3S CINDY Z74 HAREM T104 ROKIL ROKIL1B
-EDDM0105 EDDS
-PBN/A1B1C1D1O1S1 DOF/210625 REG/DAIZD RMK/TCAS)
```
However, since this format can be somewhat unclear and prone to errors during manual entry, VATSIM provides both controllers and pilots with various input forms for the flight plan (see below)
## Flight strip
Controllers on Euroscope see the most important information from the flight plan on the flight strip. This can be displayed by pressing the F6 key.
[](https://knowledgebase.vatsim-germany.org/uploads/images/gallery/2022-10/atd-flugstreifen.png)
*Euroscope flight strip for a flight from Frankfurt to Munich.*
## Flight plan fields for controllers
In most cases, the standard Euroscope flight plan window is used to process flight plans. With the **TopSky plugin**, there is also a separate flight plan window for controllers. The content is mostly the same but displayed differently. The following lists mainly refer to the Euroscope flight plan window. It's important to note that these differ from the official ICAO flight plan form!
| [](https://knowledgebase.vatsim-germany.org/uploads/images/gallery/2022-10/atd-es-fpl.png)
| [](https://knowledgebase.vatsim-germany.org/uploads/images/gallery/2022-10/atd-ts-fpl.png)
|
| *Euroscope flight plan*
| *Topsky flight plan* |
| Euroscope | Topsky | Meaning |
| Callsign | Callsign | Callsign |
| IFR/VFR | FRUL | Flight rules |
| AP data | ATYP | Aircraft type / equipment |
| Origin | ADEP | Departure airport |
| Destination | ADES | Destination airport |
| Alternate | ALTN | Alternate airport |
| TAS | TAS | True Air Speed (TAS) |
| Altitude | RFL | Cruising altitude |
| Squawk | ASSR | Transponder code |
| Dep EST | EOBT | Estimated Off-Block Time (EOBT) |
| Actual | -- | Actual time |
| Temp alt | PEL / CFL | Temporary altitude |
| Enroute | EET | Estimated flight time |
| Fuel | -- | Amount of fuel on board |
| RFL | -- | Requested flight level |
| Route | RTE | Planned route |
| Remarks | Other | Remarks |