Pre-Determined Risk Assessment. A set of circumstances that have been predefined and allow a simple declaration by the pilot in order to fly within.

Pilot in Command.

Permission for Commercial Operations. The CAA granted permissions that allow a pilot to fly their drone commercially.

Operating Safety Case. An additional set of CAA permissions allowing a pilot to operate their aircraft outside of standard permissions, at reduced distances for example.

Operations Manual. A document detailing everything about a pilot's business model and operation that must be up to date and submitted to the CAA on an annual basis to maintain a PfCO

Obstacle Avoidance System. Allowing an aircraft to detect obstacles or hazards and take automatic steps to avoid collision with them.

National Qualified Entry. An organisation given authority by the CAA to train pilots and pass them as qualified as part of the PfCO application process.

Notice to Air Men. A CAA issued time sensitive notice to all pilots to make them aware of unusual conditions or temporary hazards in the airspace.

Nautical Mile. Equivalent to one minute of latitude which is sometimes used as a measure of distance in aviation.

No Fly Zone - an area where flights are restricted or forbidden according to the law.