As a controller, it is your responsibility to ensure that the aircraft's flight plan is valid. While this may seem trivial, it can be daunting especially when starting out as an ATCO. Incorrect flight plans may route through restricted airspace, not comply with noise abatement procedures, use outdated and unusable fixes, or even cause conflicts in the air.
It is the controllers responsibility to ensure that the flight plan complies with altitude, airway, SID and STAR restrictions while it remains in the UK. In the real world, all international flight plans would undergo multiple checks to ensure its validity, however on the Network we do not have that luxury. Controllers cannot be expected to learn all of the restrictions of airports and airspace in the world, and as such we limit this to the UK airspace. This also highlights the need for en-route controllers to be able to spot mistakes quickly for aircraft entering UK airspace.
In this section we will delve into what makes a flight plan valid, break it down into multiple parts, make sure you know how to read it, and most importantly how to spot mistakes and/or inaccuracies.