Drones and surveying

The use of drones and related technology is becoming commonplace among the surveying and mapping professions. However, even though the technology is becoming more adaptable and user friendly, the underlying legal framework for operation must still be taken into account if surveyors are to avoid breaking the law.

Surveyors have many potential uses for drones:

  • Surveying large scale agricultural areas, individual properties or hard to locate areas.
  • Reducing health and safety risks.
  • Less disruption since pilots only require a clear line of sight for the drone's destination.
  • Better images and improved environmental friendliness.

Unmanned aircraft (UAVs or drones)

Irrespective of their size, these are still classified as aircraft. The person in charge of operating the controls of an unmanned aircraft is referred to as the pilot. The UK’s Civil Aviation Authority (CAA) will not allow unmanned aircraft to present or create a greater hazard to anyone (or anything) than the equivalent operations of manned aviation. The CAA oversight of unmanned aircraft is based solely on safety considerations. It does not regulate any wider issues, such as privacy or nuisance.

Small unmanned aircraft (SUAs)

Aircraft of 20kg or less are classified as small unmanned aircraft. They do not require any specific CAA airworthiness certification but operators should remember that the pilot is at all times legally responsible for the safe operation of the aircraft. Anyone operating a small unmanned aircraft for commercial operation (i.e. for which he/she is receiving remuneration) requires permission to operate from the CAA.

Flying drones and related technology

Flying outside congested areas

Pilots must maintain direct unaided visual contact with the aircraft at all times; within the UK, such ‘visual line of sight’ operations are normally accepted to a maximum distance of 500m horizontally and 400ft vertically from the pilot. In this context, ‘unaided’ does permit the use of corrective spectacles. Flight beyond these distances can be permitted, but the operator is required to provide explicit proof that this can be conducted safely. Some unmanned aircraft have a facility to provide the user with a video stream of the flight from an attached camera, which gives an impression of the flight from ‘on board’ the aircraft. The video stream can be viewed on a handheld device such as a smartphone or special visors and goggles. It should be pointed out, however, that such ‘first person views’ are not considered suitable for collision avoidance purposes and hence the aircraft must still be visually observed by the pilot during its flight in order to comply with the law.

Flying in congested areas

Operators of small unmanned aircraft being used for surveillance or data acquisition which involves flying close to people or objects require permission from the CAA, whether or not they are undertaking commercial operation. Specifically, this means flight over or within 150 metres of any congested area, over or within 150 metres of an organised open-air assembly of more than 1,000 persons, or flight within 50 metres of any person, vessel, vehicle or structure that is not under the control of the pilot. ‘Congested Area’ means, in relation to a city, town or settlement, any area which is substantially used for residential, commercial, industrial or recreational purposes.

Flying in controlled airspace

If the flight is to be conducted within ‘Controlled’ Airspace, or within the Aerodrome Traffic Zone ATZ of an airfield (the dimensions of an airfield ATZs vary, but encompass the airspace within either a 2nm or a 2.5nm radius of the airfield) permission to fly an aircraft with a mass of more than 7kg must be obtained from the Air Traffic Control (ATC) unit/authority and the flight must be operated in accordance with that permission and any additional restrictions required by ATC. To obtain an operating permission, an operator has to prove a sufficient level of competence and an understanding of the safety implications – the CAA will ask to see an up-to-date operations manual for the requested activities and evidence that the pilot is sufficiently competent. A risk assessment / method statement will be required for the flight concerned. These requirements are aimed at the protection of people and property which are not involved in the activity and are considered proportionate to the scale of activity taking place.

With regard to pilot qualifications, in order to grant a permission, the CAA would need some proof of the pilot’s overall airmanship skills and awareness and his/her ability to operate the aircraft safely. This is not a ‘Civil Pilots Licence’, but it is an independent assessment of an individual’s knowledge and operating capabilities.

CAA permission is not necessarily required for each individual flight, but the details of what is and is not permitted will be listed on each individual operator’s permission.

UAs between 20kg and 150kg

Larger unmanned aircraft are required to comply with the full requirements of the Air Navigation Order under UK regulations in the same way as any other manned aircraft operation. This includes the requirement for a Certificate of Airworthiness, a properly licensed pilot, the ability to comply with the rules of the air etc. However, the CAA may be prepared to exempt an aircraft operation from some of these requirements if a suitable safety case can be offered in respect of the level of airworthiness assurance and the intended flights. The CAA may issue an exemption on the basis of its own investigations or by recommendation from an organisation approved under BCAR A8-22. Currently only one organisation has received such approval.

Larger aircraft

Larger unmanned aircraft which need to be flown at extended ranges from their pilot are currently being tested for military and civilian applications. The airworthiness requirements for these larger unmanned aircraft are equally as stringent as those required for the equivalent manned aircraft. To ensure safety, these tests are flown in ‘segregated’ airspace, which is essentially closed to other aircraft. If large unmanned aircraft are to be allowed to operate in ‘non-segregated’ airspace (in the presence of other aircraft), a ‘detect and avoid’ capability, which replicates a traditional pilot’s ability to look out of the aircraft, will be required. This technology will be necessary for unmanned aircraft to safely integrate in shared airspace with manned aircraft, such as light aircraft and fast military jets. Until unmanned aircraft have the ability to intuitively avoid other airspace users, in the same way as manned aircraft should, then they will not be allowed to operate outside of ‘segregated’ airspace.


The Regulations relating to all flying operations within the UK are contained within CAP393 Air Navigation: The Order and the Regulations (ANO 2016). Additional requirements for UAs are published in CAP722.

Further guidance for keeping your drone flight safe and legal