IFR route planning[PDF]
- 1 Introduction
- 2 General Concepts
- 3 Specific Regulations
- 4 Route Creation
- 5 Conclusion
- 6 See also
- 7 Reference
- 8 Author
This document will introduce you to IFR route planning methods.
Through the reading of these pages, we are going to learn many things about route planning. We will review a few regulations, including some specific airspaces, before moving onto the heart of the subject with learning how to build a route, using both simple and sophisticated tools to match it with the several restrictions that happen to exist.
Flying an aircraft is often a way to go from an origin A to a destination B. As the earth is a sphere, there are many different ways to fly between these points.
- Loxodromy: A course-constant route between 2 points on earth.
- Orthodromy: A great circle route between 2 points on earth. This one is always the shortest.
Below, you can see the differences for a route between Paris and Mexico City.
The upper line like a circle arc is the orthodromy.
The lower line is course-constant and is the loxodromy.
An airway is a volume in which an airplane is protected in regard to terrain collision and availability of its navigation means. Due to the fact that several airways may intersect, it cannot be protected for collisions. It is still up to both the pilots and the ATCs to monitor the traffic.
The volume dimension of an airway is defined by each national AIP. An airway is often created between two navigation points (VOR, NDB, DME, intersections...) between which traffic flow is substantial.
Each country will then publish a list including all navigation fixes included along each airway.
The minimal en-route altitude, the parity and direction are sometimes mentioned when needed.
There may be various reasons for that but the most common are:
- Airspace does not have any airways
- Weather & Wind
- Too many restrictions/constraints
- Poor airway interconnection
Departures and arrivals: SID/STAR
Some airports do not have these kinds of procedures. Regulation permits aircraft to join their first en-route point directly as omnidirectional departure or to join the Initial Approach Fix (IAF) directly as omnidirectional arrival.
Along with flying a correct route, you must also fly at the correct altitudes.
Some airspaces have dedicated regulations and some will apply specific parity to an airway.
- Follow the Series of FL stated on AIP publications, by charts and ATS Routes information / (recommendation seems a bit light)
- Use the local semi-circular rule (if AIP is not available for public or AIP does not state specific use) / (local semi-circular is a better choice, to prevent cases of where the E/W semi is not used)
Chart links can be consulted on IVAO here.
Practically, regulations require for a twin-engine air transport aircraft to fly not further than 60 minutes to an airport considering the flight time for single engine operations. It is however possible for an operator to obtain an accreditation from its State Authority to operate outside this 60-minute restriction. This accreditation must be obtained for each aircraft.
Flight planning should take into consideration this parameter.
- Shanwick Radio
- Gander Radio
- New York Radio
- Santa Maria Radio
The regulations allow a lateral separation as little as 50.5NM, up to 60NM, for aircraft operating between FL285 and FL420.
It enables also a longitudinal separation of 15 minutes.
Daily publications can be found here.
Free Route Airspaces
For in-transit flights, a direct-to across the airspace is given. For inbound flights within an airport of the airspace, an appropriate direct-to from the entry to the beginning of the IFR procedure (STAR/Approach) or to the airfield for VFR flights will be given.
For outbound flights within an airport of the airspace, an appropriate direct-to from the airfield or from the end of the IFR procedure to the exit waypoint will be given.
SkyVector.com is a website that allows you to display worldwide aeronautical en-route charts. It is particularly useful as it displays both VFR and IFR en-route charts, at both lower and upper levels.
On the top right corner of the map, you can decide which charts you want to use. On the top left corner of the map, you can look for specific navigation waypoints (VOR, NDB, Waypoint...). You can also enter a flight plan and obtain a complete nav log.
The map will let you pick the airways or the flightpath you want to fly along. You can also obtain the bearing and the distance of a waypoint related to another, which can be helpful for VFR navigation.
You must build it manually. It is the best way to learn how to build a route, and understand the restrictions related to its usage.
Route Finder is a website that allows you to create a route from an airport to another between two cruise flight levels you will choose. It gives you all the useful information you need: route, distances, track and times amongst others. It will also try to decide which SID and STAR fit the best for your route and will try to find North Atlantic Tracks if necessary.
To use it, simply fill the form on the top of the page.
The result page will display you the full navigation log.
- High corresponds to the upper airspace (FL>FL200 to FL265 in function of airspace)
- Low corresponds to the lower airspace for low altitude flights (short IFR flights or low performance aircraft)
IVAO Route Database
Simply fill the form to find your route.
If several routes exist, the system will show them all.
Requests can be made on the IVAO Forum to obtain specific routes.
Simply register/log on the website. Then you will be able to search through the numerous amounts of flight plans. Flight plans are sorted by date, the most recent comes first. You will be eligible to file your own request after a 30-day period.
Simply enter your flight number and the airline (Only real flights are accepted). If you want to see a route, you can also enter the departure and the arrival ICAO codes and it will display all the known flights between those two airports.
It is required to create an account in order to access the website.
In the system you must create a fictive aircraft before searching your flight plan.
This tool can also manage a fleet of aircraft in order to make the validation of your routes easier.
Route Validation: Eurocontrol Route Editor
You have two ways to use this tool:
- Free(-text) editor: you should file the flight plan according to the OACI ATFN Standards.
- Structured text editor: the form is representing an actual flight plan and it allows you to fill the fields more easily.
Once you have entered your flight plan, the system will check it and will generate errors regarding:
- Restricted airspaces
- Wrong flight level
- Inadequate airways
Nowadays, we have numerous tools to help us build a route, matching reality, and in accordance with world-wide regulations.
- Fuel Planning
- Weather forecasting
- Aircraft performances
- VID 200696 - Creation
- VID 531824 - Wiki integration
DATE OF SUBMISSION
- 22:43, 1 June 2021
- This documentation is copyrighted as part of the intellectual property of the International Virtual Aviation Organisation.
- The content of this documentation is intended for aviation simulation only and must not be used for real aviation operations.