This section describes the actions to take if there has been an occurrence involving an unmanned aircraft, and describes how to report it, and to whom.
Latest information
UAS occurrence reporting is evolving and the CAA may make changes to occurrence reporting policy and guidance from time to time.
We will publish any relevant updates to occurrence reporting policy and guidance on our website.
The purpose of occurrence reporting
Occurrence reporting systems are not established to attribute blame or liability. Occurrence reporting systems are established to learn from occurrences, improve aviation safety and prevent recurrence.
The purpose of occurrence reporting is to improve aviation safety by ensuring that relevant safety information is reported, collected, stored, protected, exchanged, disseminated and analysed. Organisations and individuals with a good air safety culture will report effectively and consistently. Every occurrence report is an opportunity to identify root causes and prevent them contributing to accidents where people are harmed.
The safe operation of UAS is as important as that of manned aircraft. Injuries to third parties, or damage to property, can be just as severe. Proper investigation of each accident, serious incident or other occurrence is necessary to identify causal factors and to prevent repetition. Similarly, the sharing of safety related information via good reporting is critical in reducing the number of future occurrences.
Who must occurrences be reported to?
There are two separate reporting requirements, for:
- The Air Accidents Investigation Branch (AAIB); and
- The Civil Aviation Authority (CAA).
It may be necessary to report to one or both. The regulations that describe these requirements are explained, below.
Occurrence reporting regulations
The applicable regulations are:
- UK (EU) Regulation 996/2010 (opens in a new tab) on the investigation and prevention of accidents and incidents in civil aviation
- UK (EU) Regulation 376/2014 (opens in a new tab) on the reporting, analysis and follow-up of occurrences in civil aviation
Note: this regulation was amended by UK (EU) Regulation 2018/1139 on common rules in the field of civil aviation (The Basic Regulation)
- UK (EU) Implementing Regulation 2015/1018 (opens in a new tab) laying down a list of classifying occurrences in civil aviation to be mandatorily reported
Occurrence reporting flowcharts
The flowcharts below explain:
- what occurrences need to be reported
- who to report to
- how to report
There is a flowchart for the open category and another for the specific category. Each flowchart contains links to sections in this guidance containing key definitions and other information to help understand why and how to report to the AAIB and/or the CAA.
Yellow boxes mean mandatory reporting is required and green boxes mean reporting is voluntary. Voluntary reporting is useful to provide opportunity for safety lessons to be learned more widely from an occurrence.
Definitions
The definitions in this section are from UK (EU) Regulation 376/2014 and UK (EU) Regulation 996/2010.
Occurrence
Any safety-related event which endangers or which, if not corrected or addressed, could endanger an aircraft, its occupants or any other person and includes, in particular, an accident or serious incident.
Accidents and serious incidents are classifications of occurrence.
Accident
An occurrence associated with the operation of an aircraft which, in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time it comes to rest at the end of the flight and the primary propulsion system is shut down, in which:
- a person is fatally or seriously injured as a result of:
being in the aircraft; or
direct contact with any part of the aircraft, including parts which have become detached from the aircraft; or direct exposure to jet blast, except when the injuries are from natural causes, self-inflicted or inflicted by other persons, or when the injuries are to stowaways hiding outside the areas normally available to the passengers and crew; or
- the aircraft sustains damage or structural failure which adversely affects the structural strength, performance or flight characteristics of the aircraft, and would normally require major repair or replacement of the affected component, except for engine failure or damage, when the damage is limited to a single engine, (including its cowlings or accessories), to propellers, wing tips, antennas, probes, vanes, tires, brakes, wheels, fairings, panels, landing gear doors, windscreens, the aircraft skin (such as small dents or puncture holes) or minor damages to main rotor blades, tail rotor blades, landing gear, and those resulting from hail or bird strike, (including holes in the radome); or
- the aircraft is missing or is completely inaccessible.
Serious incident
An incident involving circumstances indicating that there was a high probability of an accident and is associated with the operation of an aircraft, which in the case of a manned aircraft, takes place between the time any person boards the aircraft with the intention of flight until such time as all such persons have disembarked, or in the case of an unmanned aircraft, takes place between the time the aircraft is ready to move with the purpose of flight until such time it comes to rest at the end of the flight and the primary propulsion system is shut down.
Fatal injury
An injury which is sustained by a person in an accident, and which results in his or her death within 30 days of the date of the accident.
Serious injury
An injury which is sustained by a person in an accident and which involves one of the following:
- hospitalisation for more than 48 hours, commencing within 7 days from the date the injury was received;
- a fracture of any bone (except simple fractures of fingers, toes, or nose);
- lacerations which cause severe haemorrhage, nerve, muscle or tendon damage;
- injury to any internal organ;
- second- or third-degree burns, or any burns affecting more than 5 % of the body surface;
- verified exposure to infectious substances or harmful radiation.
Additional UAS occurrences that must be reported
In addition to Accidents and Serious Incidents other, more UAS specific occurrences must also be reported should they or a similar occurrence be experienced or observed. These occurrences are listed below but the list is not exhaustive.
When considering whether an occurrence is reportable, you should also take into account other situations where the same thing could have happened. For example, the actual occurrence may have been ‘benign’ as it happened in a remote area. However, if the full scope of how the aircraft could be operated is taken into account, for example over people, could the same occurrence in a different situation result in a more serious outcome?
Operation of the aircraft
- Unintentional loss of control
- Loss of control authority over the aircraft
- Aircraft landed outside the designated area
- Aircraft operated beyond the limitations established in the relevant operating category or operational authorisation
- Aircraft operated without required licencing, registration or operational authorisation
- Aircraft operated in an unairworthy or unflightworthy condition
Technical malfunction/failure of the aircraft or command unit
- Loss of command-and-control link (C2 link)
- Battery failure/malfunction
- Powerplant failure
- Aircraft structural failure (for example, part of the aircraft detaches during operation)
- Errors in the configuration of the command unit
- Display failures
- Flight programming errors
- Navigation failures
Confusion/liaison errors between flight crew members (human factors)
- Inter crew communication
- Briefing
- Competency oversights
Interaction with other airspace users and the public
- Conflict with another aircraft, such that a risk of collision may have existed
- Infringement of airspace restrictions (Including Flight restriction zones (FRZs) around aerodromes and space sites)
- Inadvertent flight within close proximity of uninvolved persons (i.e. within the prescribed separation distances)
Other emergencies
- Any occurrence where the safety of the aircraft, operator, other airspace users or members of the public is compromised or reduced to a level whereby potential for harm or damage is likely to occur (or only prevented through luck).
Reporting a UAS occurrence to the AAIB
The purpose of the AAIB is to improve aviation safety by determining the circumstances and causes of air accidents and serious incidents and promoting action to prevent recurrence.
What UAS occurrences must be reported to the AAIB
All UAS accidents and serious incidents are required to be reported to the AAIB, regardless of weight or whether they are being used for commercial purposes.
Who must report UAS occurrences to the AAIB?
Any person involved who has knowledge of an aircraft accident or serious incident in the UK must report it to the AAIB. ‘Any person’ includes (but it not limited to) the owner, operator, and remote pilot of a UAS. A more detailed list can be found on the AAIB website.
How to report a UAS accident or serious incident to the AAIB
Details of how to report a UAS accident or serious incident can be found on the AAIB website (opens in a new tab).
When making a report, UAS operators should also include their ‘operator ID’ (registration) number, and state whether an operational authorisation is held.
The AAIB UAS investigation policy
The AAIB policy is to investigate accidents and serious incidents to UA where they are:
- operated under a CAA operational authorisation (i.e. in the specific category)
- the UA is certified
- the UA has a take-off weight greater than 20kg; or
- the UA has caused a serious injury or fatality
A non-fatal accident involving an uncertified UA without an operational authorisation may be investigated if there was a risk to life, potential for injury, or there are expected to be lessons to be drawn for the improvement of aviation safety.
Contact the AAIB (opens in a new tab) if you have any questions about their investigation policy.
Preservation of evidence after an incident
The law requires that you preserve evidence following an accident.
Regulation (EU) 996/2010 Article 13 Para 2 says:
‘Pending the arrival of safety investigators, no person shall modify the state of the site of the accident, take any samples therefrom, undertake any movement of or sampling from the aircraft, its contents or its wreckage, move or remove it, except where such action may be required for safety reasons or to bring assistance to injured persons, or under the express permission of the authorities in control of the site and, when possible, in consultation with the safety investigation authority.’
Contact the AAIB if you have any questions about this law.
If you have questions about reporting to the AAIB
Contact the AAIB (opens in a new tab) if you have any questions about reporting occurrences to the AAIB or what to do after an accident.
Reporting UAS occurrences to the CAA
How to report a UAS occurrence to the CAA
Reports are submitted to the CAA using the European Co-ordination Centre for Accident and Incident Reporting Systems (ECCAIRS2) reporting portal.
The reporting portal can be found here. Guidance on how to use the portal can be found in CAP 1496. When making a report, UAS operators should also include their ‘operator ID’ (registration) number, and state whether an operational authorisation is held.
It should be noted that when selecting the UK, within this system, it explains that the user is reporting as an ICAO state, and not under regulation EU 376/2014. This is because the UK has left the EU, and so reports are made under the UK version of that regulation, rather than the EU version.
Specific Category operations
The CAA will expect reporting in accordance with the specific category flowchart when an occurrence takes place at a time when the aircraft or its remote pilot is doing something that does require authorisation.
The CAA will expect reporting in accordance with the open category flowchart when an occurrence takes place at a time when the aircraft or its remote pilot is doing something that does not require authorisation.
Operators and remote pilots carrying out flights in the specific category must be familiar with the guidance of this document and the reporting requirements in their authorisation.
This approach is intended to minimise the mandatory reporting requirement on operators and remote pilots. It will also keep mandatory reporting requirements aligned and proportionate to the safety risk of the operation.
Further information on mandatory and voluntary occurrence reporting
Further information can be found on our website.
Reporting analysis and software solutions for organisations
Further guidance for organisations can be found on our website
Voluntary occurrence reporting: Confidential Human Factors Incident Reporting Programme (CHIRP)
Although the CAA MOR process is the default method of reporting incidents, there are circumstances when a reporter may not wish to report through the normal process for personal reasons (for example if they fear that their identification will result in retribution) or if they have been unable to achieve a resolution through normal channels.
The UK Confidential Human Factors Incident Reporting Programme (CHIRP) compliments the occurrence reporting system detailed in 2.9.10 above and any other formal reporting systems, by providing a means by which individuals are able to raise safety-related issues of concern without being identified to their peer group, management, or the CAA.
CHIRP is a totally independent programme for the collection of confidential safety data, and when appropriate, acting or advising on information gained through confidential reports.
Independent advice is provided on aeromedical and human factors aspects of reports, involving such topics as: errors; fatigue; poor ergonomics; management pressures; deficiencies in communication; or team performance.
Reports may include, but are not confined to, the design and use of aircraft and equipment; rules and procedures; regulations; workplaces; manpower; organisation; management; communication; human skills; and training.
Report an occurrence to CHIRP (opens in a new tab).
There is more information on CHIRP on our website
The fundamental principle underpinning CHIRP is that all reports are treated in absolute confidence in order that reporters’ identities are protected. CHIRP offers a confidential alternative for those who wish their identities to be protected. CHIRP does not accept reports submitted anonymously.