Drone sightings by commercial aircraft are on the rise, going from zero reports in 2013, steadily rising over the last few years, with 2017 seeing 92 reports in UK airspace. There have been numerous cases of airspace and aerodromes being closed due to reports of drones in the vicinity. The UK and many other countries do not yet have standard procedures to deal with drone sightings near aerodromes or violations of controlled airspace by drones. These guidelines, produced by BALPA and the Guild of Air Traffic Control Officers, are not a one-size-fits-all solution due to the dynamic and unpredictable nature of drone encounters but can be used to support the implementation of standard procedures and help pilots and air traffic controllers handle drone reports as safely as possible.
A drone strike can be much more severe than a bird strike, due to the solidity of its constituent components. Tests have shown that relatively small drones can penetrate aircraft windows and cause significant damage to aircraft structures. It is important therefore to slow down to reduce the kinetic energy of a potential drone impact. Impact energy is proportional to the speed squared, so the safest thing is to slow down.
In particular, it is recommended that when a drone report is received:
- Reduce speed to minimum clean during climb and descent
- Reduce speed to 180kt during approach.
While even small drones have been observed above 10,000 feet, pilots are more likely to encounter a drone at lower levels, during departure and approach phases. In principle, it should not be a problem to request to reduce speed to 180kt when on a STAR, initial or intermediate approach. If the aircraft is already at 180kt or less, continue with assigned speeds.
The speed reduction should be requested first so ATC can assess the traffic situation and accommodate the request safely. Further speed reductions below 180kt can be requested but may not be possible due to final approach separation requirements.
Helicopters are especially vulnerable to the damage that a collision could do. The speeds mentioned in this guidance refer to large aircraft, however, the principle of reducing speed to reduce impact energy still applies. Helicopter pilots should ensure that they use helmet visors if provided.
If a drone is seen, pilots must report the sighting to ATC and provide as much accurate information as possible. It is particularly important to pass sufficient information to ATC to positively identify it as a drone:
- Lateral and vertical separation
- Was it moving or stationary?
- Size, shape and appearance (e.g. quadcopter, camera underneath, colour, lighting etc.)
ATC must in turn inform supervisors, neighbouring sectors and pilots already on and joining the frequency. Supervisors will take appropriate action, liaise with other units and, if deemed necessary inform the authorities and police. Prosecution of unlawful interference with flight operations can only happen if authorities are informed promptly and react quickly. ATC should continue to inform pilots joining the frequency for 30 minutes after the initial drone sighting or any subsequent sighting. Associated contingency procedures are likely to remain active for, at least, 30 minutes or until confirmation is obtained that the situation has been resolved.
Drone sightings can lead to the closure of airspace or aerodromes for a considerable time. Pilots should expect delays and plan for an early adjustment of the flight profile and consider diversion options. Pilots should take into account the lower speeds and the increased track miles due to aircraft ahead flying more slowly and possibly being vectored away from areas of reported drone activity.
A drone sighting and the potential delays and airspace or aerodrome closures can increase radio-telephony usage (e.g. minimum fuel calls and diversion requests). Pilots and controllers should be prepared for possible frequency congestion, use standard phraseology throughout and make efficient use of the frequency.
Due to the nature of drone operations, its exact position can change rapidly, making it difficult to request or provide effective avoidance instructions. In addition, due to the traffic situation, it may not always be possible to vector aircraft away from the area where the drone was originally seen. Pilots may request alternative vectors if deemed necessary. However, in order to maintain safety and a steady flow of air traffic ATC instructions, should whenever able, be followed.
Until appropriate legislation concerning drone visibility is introduced, air traffic controllers have no precise information about the location and direction of travel of the drone, so an attempt to vector aircraft around the affected airspace may be counterproductive. Air traffic controllers are advised to consider the safety of the operation and avoid the area of reported drone activity if deemed necessary.
After the event, pilots and controllers must file the corresponding safety report so the appropriate post-incident analysis or safety investigation can be carried out. Please include as much detail as possible about the drone, the risk to aircraft and the effect on the safety of the operation. Detailed information is particularly important in order to satisfy the criteria national authorities (e.g. UK Airprox Board) use in their assessment of risk.
It is only by enhancing awareness among the general public that society will become more aware of the problems and risks associated with unlawful use of drones.
The Drone Sighting Checklist
Pilots: if a drone has been reported, consider requesting a speed reduction:
» Initially to minimum clean, including during departure
» On STAR, initial or intermediate approach, request a further reduction to 180kt
» On final approach observe ATC speed constraints to maintain separation
ATC: expect pilots to request a speed reduction
Pilots: if a drone is seen, inform ATC immediately and pass as much accurate information as possible about the drone sighting:
» Lateral and vertical separation
» Was it moving or stationary?
» Size, shape and appearance (e.g. quadcopter, camera underneath, colour, etc.)
ATC: inform supervisors, neighbouring sectors and pilots on and joining the frequency
Pilots: plan for possible delays or diversions
ATC: plan for possible delays and/or closure of airspace or aerodrome
Pilots: request alternative routeings or radar vectors if deemed necessary
ATC: consider the safety of the operation and avoid the area if deemed necessary
Pilots: file the appropriate safety report as established by your airline.
ATC: file the appropriate safety report as established by your ANSP.