Guide for Fire hose carrying drones

Fire hose carrying drones represent an emerging category of unmanned firefighting systems designed to move hoses, nozzles or water-delivery equipment into locations that may be difficult, dangerous or slow for firefighters to reach. Rather than carrying a large quantity of water onboard, these drones can remain connected to a ground-based water source through a hose, allowing water or firefighting agent to be supplied continuously while the aircraft positions the nozzle.

This concept is significantly different from conventional firefighting drones that carry small tanks or drop extinguishing material. Water is extremely heavy, with one litre weighing approximately one kilogram, meaning the amount that can realistically be carried by most drones is limited. A hose-connected system can potentially overcome this limitation by keeping the main water supply on the ground while the drone carries only the hose, nozzle and associated equipment.

Potential applications include high-rise building fires, industrial facilities, warehouses, roofs, inaccessible structures, hazardous-material incidents, ports, ships, storage tanks, tunnels, wildland-urban interface fires and locations where approaching the fire directly creates unacceptable risk for personnel.

However, carrying a pressurised fire hose from a drone creates substantial engineering challenges. The aircraft must manage the weight of the hose, water contained inside it, aerodynamic drag, nozzle reaction forces and the changing forces created as the drone moves. A firefighting drone therefore needs to be designed as an integrated system rather than simply attaching a conventional fire hose to a large multirotor.

The strongest concept is generally ground-supplied water + appropriately engineered hose + aerial hose management + stabilised nozzle + thermal and visual sensing + trained firefighter control.

What Is a Fire Hose Carrying Drone?

A fire hose carrying drone is an unmanned aircraft designed to transport or position a firefighting hose or nozzle.

There are several possible configurations. A drone may simply carry a lightweight hose to firefighters or another location. A larger aircraft may lift a dry hose into position before it is pressurised. More specialised systems may remain connected to the hose and actively direct a stream of water or firefighting agent while hovering.

The most technically demanding version is effectively an aerial firefighting nozzle.

Water remains supplied from a pump, fire engine, hydrant or dedicated ground system. The drone provides mobility and positioning.

This arrangement potentially allows firefighters to direct water into locations where deploying an aerial ladder, firefighter or ground monitor would be difficult.

Why Use a Drone Instead of Carrying Water?

Water weight creates a fundamental limitation for airborne firefighting.

Even a heavy-lift drone capable of carrying 50 kg could theoretically carry only around 50 litres of water before accounting for the tank, pump and other equipment.

A substantial firefighting flow could consume that amount extremely quickly.

Increasing aircraft size does not completely solve the problem because carrying hundreds of litres requires very large aircraft.

A ground-fed hose changes the equation.

Instead of lifting the complete water supply, the drone only supports the hose and nozzle assembly while water is continuously pumped from the ground.

This potentially provides far longer operating duration.

The Hose Is Part of the Payload

In a conventional drone, payload weight is relatively constant.

A hose-carrying drone is different.

As the aircraft climbs, it may need to support an increasing length of hose. When water begins flowing, the hose becomes considerably heavier.

The hose also creates aerodynamic drag and can pull the aircraft sideways.

For this reason, the hose cannot be considered separately from the aircraft.

Drone, hose, nozzle, pump, water pressure, control system and flight software should be engineered as one system.

Hose Weight

The total suspended weight includes the hose itself plus the water contained inside it.

A larger hose can carry substantially more water but also becomes considerably heavier.

For aerial systems, hose diameter therefore becomes an important design compromise.

A smaller lightweight hose reduces the load on the drone but restricts achievable water flow and increases pressure losses.

A larger hose supports greater flow but requires a significantly larger aircraft.

The optimum design depends on whether the drone is intended for cooling, targeted suppression, structural firefighting or another specialised role.

Hose Drag

Weight is only one part of the problem.

A long suspended hose acts like an aerodynamic object.

Wind can push the hose sideways and create forces on the aircraft.

These forces can change along the entire hose length.

The drone’s flight controller therefore needs sufficient control authority to maintain position while the hose moves.

Wind conditions acceptable for an ordinary inspection drone may be unsuitable for a hose-carrying aircraft.

Water Pressure

Water needs sufficient pressure to travel from the ground to the drone and produce an effective stream.

As elevation increases, pressure losses become increasingly important.

Additional pressure is also lost through hose friction, fittings and nozzle restrictions.

The ground pumping system therefore needs to be matched specifically to the aerial system.

Simply connecting the drone to an ordinary pump without considering elevation and flow requirements may produce inadequate nozzle performance or excessive hose forces.

Nozzle Reaction Force

When water leaves a nozzle, an opposing force acts on the nozzle assembly.

Firefighters experience this as nozzle reaction.

A drone experiences the same physical effect.

If the nozzle is attached directly to the aircraft, this reaction can disturb its position and attitude.

The higher the water flow and exit velocity, the greater the engineering challenge.

The aircraft therefore needs sufficient thrust and an appropriately designed nozzle arrangement.

Flight-control software may also compensate for predictable forces while water is flowing.

Stabilised Nozzle Systems

Rather than rigidly fixing the nozzle in one direction, an aerial firefighting drone may use a controllable nozzle mount.

The drone maintains its overall position while the nozzle is aimed independently.

This reduces the need to rotate or tilt the entire aircraft every time firefighters want to redirect the stream.

A stabilised nozzle can also allow an operator to make smaller targeting adjustments.

The design needs to account for water reaction forces and should remain within the aircraft’s safe operating envelope.

Hose Management

Hose management may ultimately be one of the most important elements of a successful firefighting drone.

Allowing a long hose to hang freely creates risks of swinging, snagging and excessive load.

A ground-based reel can release hose as the drone climbs.

Active reel systems could potentially control tension so that excessive slack does not develop.

Sensors could monitor hose tension continuously.

If loads exceed predefined safety limits, the system could warn the operator or prevent additional movement.

Ground-Based Hose Reel

Keeping the majority of the hose on a controlled ground reel can simplify deployment.

As the drone climbs, the reel releases only the required length.

This can reduce tangling.

A motorised reel could maintain controlled tension.

However, it must not pull strongly against the aircraft.

The drone and reel control systems therefore need to work together.

The reel should also allow emergency recovery if the aircraft needs to return quickly.

Intermediate Hose Support

For greater operating heights, using one aircraft to support the entire hose may become inefficient.

Intermediate support could potentially distribute the load.

This might involve specialised support points or additional aerial systems, although such concepts add significant operational complexity.

Another possibility is routing the hose against a building or through an engineered support system rather than suspending its entire weight vertically.

The objective is to reduce the amount of load transferred directly to the firefighting drone.

High-Rise Firefighting

High-rise buildings are one of the most frequently discussed applications.

A drone could potentially position a firefighting stream near windows, façades, balconies or roof areas that are difficult to reach from ground equipment.

Thermal imaging could help identify areas of elevated surface temperature.

However, high-rise fires create extremely difficult flight conditions.

Heat, smoke, turbulent air, falling debris and strong winds around buildings can all affect the aircraft.

The drone should therefore complement established firefighting systems rather than being treated as a replacement for sprinklers, standpipes, aerial appliances or internal firefighting teams.

Roof Fires

Roof areas can sometimes be difficult to access safely.

A hose-carrying drone could potentially position water onto selected external roof areas while personnel remain farther away.

Thermal imaging may help identify surface temperature differences and monitor cooling.

However, thermal imagery cannot reliably reveal every concealed fire inside a roof assembly.

Professional firefighters must continue to assess fire behaviour and structural risk.

The drone provides an additional delivery and observation tool.

Warehouse Fires

Large warehouses can create challenging firefighting conditions because of their scale and roof height.

Aerial hose drones could potentially direct water toward selected exterior or accessible areas.

Thermal cameras can provide additional information about heat distribution.

However, smoke and roof structures can limit visibility.

A drone should not enter a structure simply because it is unmanned.

Collapse, heat and obstacles can destroy the aircraft and potentially create additional hazards.

Industrial Fires

Industrial sites can contain tanks, machinery, pipes and hazardous substances.

Keeping personnel farther from the immediate hazard may be valuable.

A hose drone could potentially support external cooling or targeted water application from a controlled stand-off position.

However, the correct extinguishing agent depends on the material involved.

Water is not appropriate for every industrial fire.

The incident commander and qualified firefighting personnel must determine the appropriate suppression method.

Storage Tank Fires

Large storage tanks can require substantial cooling and suppression resources.

A drone may potentially position a nozzle around difficult-to-reach exterior sections.

However, the heat, plume and potential hazardous atmosphere make these environments extremely demanding.

Conventional fixed monitors and specialised firefighting systems remain essential.

The drone’s role would most realistically be supplementary, particularly for observation and limited targeted application.

Chemical and Hazardous-Material Incidents

One advantage of unmanned firefighting is reducing personnel exposure.

A drone may be able to approach an area where toxic smoke or chemical hazards make human access undesirable.

Thermal, RGB and appropriate gas sensors can provide situational information while the hose system supports cooling or another authorised response.

However, the drone itself may become contaminated.

Decontamination and equipment disposal procedures should therefore be considered before deployment.

Battery Fires

Battery energy-storage systems and electric-vehicle fires present specialised firefighting challenges.

A drone could potentially provide remote cooling or support monitoring in selected external scenarios.

Thermal imaging can help identify areas of elevated surface temperature and monitor changes.

However, battery fires require specialist procedures, and thermal-camera readings alone cannot determine the complete internal condition of a battery pack.

The drone should operate under established firefighting protocols.

Ship and Maritime Fires

Ships contain high structures, confined areas and locations that may be difficult to reach from the quay.

A hose-carrying drone could potentially support external firefighting around decks or superstructures.

Ports might also use drones to provide rapid observation before specialist firefighting resources arrive.

However, maritime environments add wind, saltwater exposure and moving-platform considerations.

The aircraft must be designed appropriately for these conditions.

Wildland-Urban Interface Fires

In areas where vegetation fires threaten buildings, drones may support targeted cooling around structures or difficult terrain.

However, a hose significantly limits the operating radius compared with free-flying wildfire drones.

The concept is therefore more suited to relatively localised operations around buildings, infrastructure or fixed water sources than broad wildfire suppression.

Crewed firefighting aircraft always require operational priority.

Tunnels

Road and rail tunnels can present difficult access conditions.

A specialised ground-fed firefighting drone could potentially move a hose or nozzle farther into a tunnel while personnel remain at greater stand-off.

However, tunnels create strong airflow, smoke, communications and navigation challenges.

GNSS will normally be unavailable.

A tunnel firefighting drone may therefore require LiDAR-based localisation, robust communications and autonomous stability systems.

Confined Industrial Spaces

Large industrial halls, hangars and similar structures may provide potential applications.

The drone could position water above machinery or inaccessible platforms.

However, operating a large multirotor indoors creates significant downwash and collision hazards.

LiDAR or other obstacle-detection technologies become particularly important.

The aircraft should also have defined behaviour if communications are lost.

Thermal Imaging

A radiometric thermal camera is one of the most valuable companion payloads for a firefighting drone.

It can show surface temperature patterns that may not be visible through ordinary cameras.

The operator can use thermal information to identify candidate areas requiring attention and monitor how temperatures change during firefighting.

However, a thermal hotspot does not automatically reveal the precise location or nature of a fire.

Smoke, materials, reflections and viewing geometry can influence thermal measurements.

Firefighters should interpret the imagery alongside other incident information.

RGB Cameras

A visible-light camera provides essential situational awareness.

It allows operators to see windows, roofs, structural obstacles and the direction of the water stream.

Zoom capability can help assess distant areas.

Combining RGB and thermal imagery gives firefighters two complementary views.

However, heavy smoke can significantly reduce visible-camera effectiveness.

LiDAR and Obstacle Detection

LiDAR can help measure the surrounding environment and identify obstacles.

This may be particularly useful around buildings, industrial facilities and tunnels.

The system could help maintain safe stand-off from walls while the nozzle is positioned.

However, firefighting environments are dynamic.

Falling debris, smoke, water spray and structural movement may create rapidly changing conditions.

Obstacle avoidance should therefore supplement rather than replace human operational supervision.

Water Spray and Sensors

The drone’s own water stream can interfere with sensors.

Spray may reach cameras or LiDAR windows.

Water droplets can generate unwanted LiDAR returns and obscure imagery.

Sensor placement therefore needs to account for the nozzle and expected airflow.

Protective windows may require hydrophobic coatings or cleaning systems.

The aircraft itself should also have appropriate water resistance.

Heat Protection

A firefighting drone may operate near significantly higher temperatures than ordinary commercial aircraft.

Motors, batteries, cameras, electronics and composite materials all have thermal operating limits.

Heat shielding may be required around vulnerable components.

However, shielding adds weight.

Temperature sensors can monitor the aircraft itself and warn the operator when safe limits are being approached.

A drone should not continue advancing simply because it can still fly.

Electronics Protection

Water and firefighting foam can damage electronics.

Connectors, motors and control systems therefore need appropriate environmental protection.

The aircraft may also encounter conductive contamination or corrosive substances.

Ingress protection becomes more important than in ordinary inspection drones.

However, an IP rating does not mean a drone is safe in every firefighting environment.

Temperature, chemicals and impact risks must also be considered.

Propeller Protection

Large firefighting drones may operate near structures, hoses and debris.

Contact between a propeller and the hose could be catastrophic.

The hose route therefore needs to remain well clear of the propulsion system.

Protective structures may reduce some risks but also add weight and affect airflow.

The complete aircraft and hose geometry should be considered during design.

Centre of Gravity

The hose connection point can affect aircraft stability.

If the hose pulls from a point far from the drone’s centre of gravity, it can create a rotational force.

An attachment close to the appropriate load path can reduce this effect.

The nozzle arrangement also affects balance.

The design should therefore consider both static payload weight and dynamic forces created during operation.

Tension Monitoring

Load cells could measure tension in the hose.

This would allow the flight-control system and operator to understand how much force is being applied to the aircraft.

Unexpected increases could indicate that the hose has snagged.

Automatic safety thresholds could prevent the drone from continuing to climb or move.

This type of sensing may become an important feature of future aerial hose systems.

Emergency Hose Release

A drone carrying a hose may require an emergency release system.

If the hose becomes trapped or creates an uncontrollable load, releasing it could potentially allow the aircraft to recover.

However, releasing a pressurised hose introduces its own hazards.

Any such mechanism therefore needs to be engineered as part of the complete firefighting system with appropriate pressure-control and ground procedures.

It should not be improvised operationally.

Communications

Reliable command and control is essential.

Buildings and industrial structures can block radio signals.

Smoke itself may not necessarily block radio communications, but the surrounding structure can.

Mesh networks, repeaters or dedicated communication infrastructure may improve coverage.

The drone should also have defined failsafe behaviour.

A conventional GPS return-to-home command may be inappropriate if the aircraft is connected to a hose.

GNSS-Denied Operations

Indoor, tunnel and partially enclosed operations may not have reliable GNSS.

The drone may therefore require visual-inertial navigation, LiDAR SLAM or another local positioning method.

This can allow it to maintain position relative to the structure.

However, GNSS-independent navigation should be validated carefully.

Smoke, water spray and changing environments can reduce the performance of optical or LiDAR-based systems.

Multiple navigation sensors may provide greater resilience.

Ground Control Station

The operator needs more information than would normally be required for an inspection drone.

The interface could display aircraft position, battery condition, hose tension, water pressure, water flow, nozzle direction, thermal imagery and environmental warnings.

Firefighters should not need to interpret several disconnected systems during an emergency.

Integrating the information into a clear operational interface can significantly improve usability.

Firefighter Control of the Nozzle

One possible operational model separates aviation control from firefighting control.

A trained drone operator manages aircraft positioning.

A firefighter controls the nozzle and water application.

This allows each person to concentrate on their area of expertise.

The incident commander retains overall control of the firefighting operation.

As systems become more autonomous, the aircraft may maintain position automatically while the firefighter concentrates on directing the stream.

Autonomous Position Holding

Once positioned, the drone may use GNSS, LiDAR, visual navigation or sensor fusion to hold a stable location.

The flight controller can compensate for wind and hose forces.

This reduces operator workload.

However, autonomous position holding should continuously assess localisation confidence.

If the navigation system becomes unreliable, the operator needs immediate warning.

Automation should support rather than conceal uncertainty.

AI-Assisted Thermal Analysis

AI may help analyse thermal imagery and identify candidate hotspots.

Software could highlight areas where temperature is increasing or where previous cooling has been ineffective.

This may help firefighters manage large structures.

However, AI cannot independently determine fire behaviour or structural safety.

Its output should be treated as additional information for trained personnel.

AI-Assisted Nozzle Positioning

Future systems may use computer vision and thermal imagery to assist nozzle alignment.

The firefighter could select an area on the screen and the gimbal could maintain the nozzle direction as the drone moves.

This may reduce workload.

However, automatic targeting of a water stream should remain subject to firefighter control.

People, electrical infrastructure and hazardous materials may be present.

Human operational judgement remains essential.

Multiple Firefighting Drones

Large incidents could eventually use several hose or monitoring drones.

One aircraft might provide thermal observation while another positions water.

Additional drones could provide communications or mapping.

However, multiple aircraft increase airspace-management complexity.

Fire services would need clear procedures to avoid collisions and ensure drones do not interfere with ladders, cranes, helicopters or other emergency assets.

Integration with Fire Engines

The most practical water source for many systems may be a fire appliance or dedicated pump.

The fire engine provides water pressure while the drone positions the delivery system.

Pump controls could communicate with the drone system.

For example, water flow could remain low during positioning and increase only once the aircraft reaches a stable location.

Integrated control could reduce sudden nozzle forces.

Hydrant Connection

A drone system could potentially operate from a hydrant through an appropriate pumping and hose-management unit.

However, available pressure varies.

The system should not assume that hydrant pressure alone is sufficient for the required elevation and flow.

A controlled pump may still be necessary.

Water-supply planning remains a normal firefighting responsibility.

Firefighting Foam

Some incidents require foam rather than water.

A hose-carrying drone could theoretically deliver suitable firefighting agents from a ground system.

However, foam characteristics and application methods differ from ordinary water streams.

Compatibility with pumps, hose and nozzle systems needs to be engineered.

Environmental restrictions may also apply to some firefighting agents.

The correct extinguishing medium remains a professional firefighting decision.

Water Mist

Water-mist systems use smaller droplets and may require less water than conventional streams for some applications.

This could be interesting for aerial firefighting because lower flow may reduce hose weight and reaction forces.

However, water mist is not suitable for every fire scenario.

Droplet size, pressure and application geometry strongly influence performance.

Any aerial water-mist concept should therefore be designed and validated as a complete firefighting system.

Hose Delivery Drones

Not every fire hose drone needs to remain airborne while water is flowing.

A simpler and potentially valuable application is hose deployment.

The drone could carry a lightweight line across difficult terrain, up a structure or to an inaccessible location.

This line could then help position a larger hose or other equipment.

Such applications may require considerably less aircraft power than sustained aerial water delivery.

They could therefore become practical sooner.

High-Rise Hose Deployment

A drone might potentially transport a dry hose or guide line to an elevated location before the line is charged.

This avoids lifting the full water-filled hose during initial positioning.

Once secured appropriately, water could be supplied through the system.

However, structural anchoring and hose forces need professional engineering.

The drone should not be assumed to support the entire operational load after deployment unless specifically designed to do so.

Search and Rescue Integration

The same firefighting drone platform could carry thermal and visual sensors to assist situational awareness.

Before water application begins, the drone may survey accessible exterior areas.

Candidate human heat signatures can be communicated to rescue teams.

However, a thermal signature does not confirm identity or medical condition, and non-detection does not confirm that an area is clear.

Search and rescue decisions remain with emergency personnel.

Structural Collapse Risk

One of the strongest reasons for using drones is keeping firefighters farther from potentially unstable structures.

The drone can approach areas that would create unacceptable personnel exposure.

However, structural collapse can also destroy the aircraft and hose system.

Falling debris may pull the hose or create hazards on the ground.

The operating area should therefore account for both aircraft and structural failure.

Interaction with Crewed Aviation

Major fires may involve helicopters or other crewed aircraft.

Crewed aviation must receive priority.

Drone operations should be coordinated through the incident command structure.

An uncoordinated drone can create serious risks to firefighting aircraft.

Hose-connected drones may operate close to a structure, but their presence still needs to be known to aviation teams.

Operational Training

Firefighters need specific training before using aerial hose systems.

Flying the drone is only one element.

Teams need to understand hose forces, pump operation, emergency release, thermal imagery, communications and airspace coordination.

Training should include simulated failures.

The objective is for the system to become another familiar firefighting tool rather than an experimental aircraft introduced during an emergency.

Maintenance

A firefighting drone will operate in harsh environments.

Water, smoke, heat, ash and chemicals can contaminate components.

Post-mission inspection should therefore be more extensive than for an ordinary drone.

Hoses, couplings and nozzles also require inspection.

Thermal cameras and LiDAR windows may need cleaning.

Aircraft exposed to hazardous materials may require specialist decontamination.

Regulations

A large hose-carrying drone may fall into a significantly more demanding regulatory category than a small inspection aircraft.

Aircraft mass, operations near people, BVLOS flight and emergency-service use may all affect requirements.

Local aviation regulations must therefore be considered during system development.

Emergency-service status does not automatically remove aviation safety obligations.

Regulatory planning should form part of the project from the beginning.

Selecting a Fire Hose Drone

The correct system should be selected according to the intended firefighting role rather than maximum payload alone.

Important factors include aircraft lift capacity, thrust reserve, hose diameter, supported hose length, water flow, operating height, nozzle reaction, wind tolerance, hose-management system, thermal camera, obstacle sensing, communications, navigation resilience, environmental protection and emergency procedures.

Maximum payload specifications should be treated cautiously.

A drone capable of lifting a static 50 kg payload does not necessarily have the control authority to safely manage a 50 kg dynamic hose load in wind while water is flowing.

Realistic testing should reproduce the actual hose, pump, pressure, elevation and environmental conditions.

Benefits of Fire Hose Carrying Drones

The principal advantage is reducing human exposure.

A drone can potentially move closer to heat, smoke, unstable structures or hazardous materials while firefighters remain at a safer stand-off.

A ground-fed water system can also provide much greater operating duration than carrying water onboard.

Thermal and visual sensors give firefighters immediate situational awareness from the same platform.

The aircraft can potentially reposition the water stream more quickly than installing temporary elevated equipment in some scenarios.

The concept may be especially valuable where conventional access is difficult but a relatively localised firefighting stream could provide meaningful support.

Limitations

Fire hose drones face substantial physical constraints.

The hose becomes heavier as elevation increases. Water adds weight. Wind creates drag. The nozzle produces reaction forces. Buildings generate turbulent airflow. Heat affects batteries and electronics.

The drone’s operational radius is also limited by the hose.

It cannot move freely in the same way as an ordinary aircraft.

Water may not be the appropriate extinguishing agent for every incident.

The aircraft may also become another hazard if it fails above firefighters or members of the public.

For these reasons, fire hose drones should be viewed as specialised firefighting tools rather than replacements for conventional fire engines, aerial ladders, fixed monitors, sprinklers, firefighting aircraft or trained personnel.

The Future of Fire Hose Carrying Drones

Future firefighting drones are likely to become increasingly integrated systems rather than conventional heavy-lift drones carrying adapted firefighting equipment.

Purpose-built aircraft could incorporate hose load paths directly into the frame.

Load cells could continuously monitor hose tension.

Ground reels could communicate with the aircraft and automatically release or recover hose.

Pump pressure could adjust according to altitude and nozzle demand.

Thermal cameras could automatically monitor areas being cooled.

LiDAR could maintain distance from structures.

AI could highlight changing thermal conditions while firefighters remain responsible for operational decisions.

Hybrid power systems or ground-supplied electrical power could potentially extend endurance further.

For some applications, the hose or tether might eventually carry both water and electrical power, reducing dependence on onboard batteries, although such systems would require careful engineering and safety validation.

The most interesting development may ultimately be a complete aerial firefighting system consisting of a drone, intelligent hose reel, pump, thermal camera, controllable nozzle and integrated firefighter interface.

A future operational workflow could operate as:

incident command identifies an inaccessible external firefighting requirement → thermal/RGB reconnaissance establishes candidate operating area → ground pump and hose-management system deployed → drone lifts dry or controlled hose → aircraft establishes safe stand-off → hose tension and aircraft stability confirmed → controlled water flow begins → stabilised nozzle directed by firefighter → thermal camera monitors surface temperature changes → aircraft and hose loads continuously monitored → water application adjusted by incident command → drone withdraws → thermal reassessment → conventional firefighting and engineering assessment continue.

Conclusion

Fire hose carrying drones have the potential to create a new form of remotely positioned firefighting equipment, allowing water or other suitable firefighting agents to be delivered to areas that are difficult or dangerous for personnel to approach.

Their most important advantage is that they do not necessarily need to carry the firefighting water onboard. By remaining connected to a ground-based supply, the drone can potentially deliver water for much longer periods than a conventional payload-carrying aircraft.

Applications could include high-rise buildings, roofs, industrial facilities, warehouses, ports, tunnels, hazardous-material incidents and other inaccessible structures.

However, the concept creates major engineering challenges. Hose weight, water weight, pressure loss, nozzle reaction, wind drag, hose tension, aircraft stability, heat and communications all need to be considered together.

The most successful systems are therefore unlikely to be ordinary drones with fire hoses attached to them. They will be purpose-designed platforms where the aircraft, hose, reel, pump, nozzle, thermal camera, navigation system and firefighter controls operate as one integrated firefighting system.

Used appropriately, fire hose carrying drones could become a valuable addition to modern fire and rescue operations—particularly where their greatest benefit is not replacing firefighters, but allowing firefighters to apply water and gather information while remaining farther away from the most dangerous part of an incident.