Flight Route Planning Pitfalls: Part 1 – What to Watch For
This business aviation blog post is part of a series on route planning pitfalls for flight planning purposes.
Business aircraft operators experienced in international operations know that routings based solely on great circle route and predicted winds are often not ideal, won’t be approved, or are not even feasible. This is due to a seemingly endless assortment of routing restrictions in place worldwide. Preferred routings – and routings based on specific airway requirements – will dictate your ultimate flight plan routing. Start your planning process as early as possible in order to obtain the best routings (based on approved airways) and required permits, as well as adhere to your own company-specific operating restrictions.
The following are some tips on what to watch for to avoid route planning pitfalls:
1. Random routings are not recommended
All international legs should use built-up routes, as opposed to random routes. There are just too many variables to consider with random routings, especially when many countries have preferred routings. Airway and routing restrictions change frequently worldwide, and many flight planning systems and scheduling software programs have limitations in terms of keeping up with those changes. Ultimately, many international trips require human input when route planning. It’s usually best to start the trip planning process with a random route, based on best winds, and then edit the route as necessary based on preferred airways, minimum en-route altitudes (MEAs), flight levels, and arrival/departure procedures.
2. Avoid the temptation to file a random route
While some operators may prefer filing random routings, there are issues with systems that create just random routes. These routes often do not satisfy the requirements of the particular countries involved. For example, many countries don’t accept off-airway direct route segments, requiring airways to be filed. Thus, certain portions of a random route may not be valid and will result in your flight plan request being rejected. For example Mongolia has preferred routings based on entry/exit fixes, and a random routing based on best winds may not match up with the preferred routing. If you’re transiting Russian, Mongolian, and Chinese airspace and are not using an approved routing, you may be faced with multiple permit revisions and, as a result, substantial operating delays.
3. Be aware of top pitfalls if appropriate route planning is not done
If an invalid route is submitted for approval, you may expect the air traffic control responsible to reject it and possibly revise your routing request. The approved revised route may add substantial distance and time to your estimated time en route and may impact passenger schedules at destination. In fact, depending on the distance involved, you may find you’re not able to make the flight leg direct, resulting in an additional tech stop. This may necessitate a new flight plan, updated ground handling arrangements, new weather and Notice to Airmen (NOTAM) packages, and a revised passenger schedule. If new permits are needed and cannot be secured in time, you may be faced with additional re-routing considerations and delays.
4. Know potential routing pitfalls
Your flight plan may be denied if you have not paid appropriate nav fees. This is a common situation with Venezuela. If nav fees are outstanding, you’ll need to re-route around that county’s airspace. For example Russia has preferred routings in place for several regions, so random routings may not work. Be aware – particularly in high-traffic areas – that preferred routings may change frequently. This is the case in the Sao Paulo area, where arrival and departure routes can change on a regular basis, as published via NOTAM.
While multiple resources are available to provide information on restrictions and preferred routings, not all resources include the same pertinent information. For example in the case of Beijing Capital (ZBAA), the "En Route Directory" sometimes indicates multiple arrival options from a single airway, while the aeronautical information publication gives only one. Additionally, when you submit a route for permit approval, the Civil Aviation Authority of China will often reply with a different, unpublished route.
Another situation, although rare, happens if waypoint lat/long data is inadvertently entered into the computer database incorrectly, resulting in an invalid fix within the flight planning system. While the program may choose the right fix name, the fix it comes up with may be in a different country. This requires human input to correct.
5. Start by looking at the "big picture"
It’s usually best to compute a random route to determine a basic route based on winds, and then plot that route. This allows you to quickly determine countries you’ll be overflying, and avoid "dog legs" and other issues for your route. Then, edit this routing to accommodate such restrictions as preferred departures/arrivals, airways, your particular standard operating procedures or insurance restrictions, etc. Remember that most countries have published routing restrictions to be mindful of, and there may also be un-published restrictions which you may encounter over time. The key is to plan early and allow yourself sufficient time to organize required permits.
A great many operating issues can be avoided by taking the time to review proposed international routings based on preferred airways and assorted permit requirements. Should you flight plan a routing that is not approved or feasible, downside risks include operational delays, additional costs, and potentially frustrated passengers with delayed schedules at destinations.
If you have any questions about this article or if you would like route planning assistance, contact me at firstname.lastname@example.org.
Later, we’ll discuss what to look out for regarding route planning.