The Fire Vehicles

The Fire Vehicles

Airport fire vehicles are among the most impressive machines you will see at any airport. They look nothing like the red fire engines you see on the streets — they are bigger, faster across rough terrain, and carry vastly more extinguishing agent. This lesson explains what types of vehicles an airport like Prestwick operates and what they carry.

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Why Airport Fire Vehicles Are Different

Ordinary fire engines are designed to drive on roads, connect to street hydrants, and fight structural fires in buildings. Airport fire vehicles face a completely different challenge:

• They may need to reach a crashed aircraft off-paved surfaces — on grass, mud, or rough ground in the runway strip or beyond the airfield boundary
• They must cover the full length of the runway (nearly 3 km at Prestwick) in under three minutes
• They must carry all the water and foam they need — there are no hydrants on a runway
• They must be able to discharge extinguishing agents at enormous flow rates — you cannot slowly spray a 1,000-degree fuel fire; you must knock it down in seconds
• They must protect themselves and their crew in an environment of intense heat and toxic fumes

These requirements produce vehicles that are more like military armoured vehicles than conventional fire engines.

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Types of Airport Fire Vehicle

Major Foam Tenders (MFTs)

These are the big ones — the backbone of any airport fire fleet. A major foam tender is a large, heavy vehicle (often 6x6 or 8x8 all-wheel-drive) that carries:

• Water: Typically 9,000-12,000 litres or more
• Foam concentrate: Hundreds of litres of Aqueous Film-Forming Foam (AFFF) or equivalent
• Dry chemical powder: Typically 250 kg or more of potassium bicarbonate powder for supplementary use

The water and foam are mixed and discharged through:

• A roof-mounted monitor (turret) — a large nozzle on top of the vehicle that can be aimed by the driver from inside the cab while the vehicle is still moving. This allows the crew to begin fire suppression before they even stop the vehicle
• Bumper monitors — forward-facing nozzles for applying agent at ground level, directly under the aircraft
• Hand lines — hoses that crew members can deploy for close-range work

A typical MFT can discharge its entire foam supply in about two to three minutes at maximum flow rate. This sounds fast, but the strategy is to apply a massive initial knock-down to suppress the fire quickly, then switch to more targeted application.

Rapid Intervention Vehicles (RIVs)

RIVs are smaller, faster vehicles designed to arrive first and begin rescue operations immediately. They are typically built on a 4x4 truck chassis and carry:

• A smaller quantity of water and foam (typically 1,500-2,500 litres of water)
• Dry chemical powder
• Rescue equipment: cutting tools, spreading tools (hydraulic rescue equipment, sometimes called "jaws of life"), axes, crowbars, and forcible entry tools
• Breathing apparatus sets
• First aid equipment
• Thermal imaging cameras

The RIV's role is speed — it reaches the scene first, applies an initial agent to create a survivable area, and the crew begin rescue operations while the MFTs are still en route.

Domestic Fire Vehicles

Some airports also maintain a smaller vehicle for responding to fires in airport buildings, hangars, or ground equipment — situations where a massive foam tender would be overkill.

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What They Carry: Extinguishing Agents

Water

Plain water is effective for cooling but not for extinguishing fuel fires on its own. Jet fuel floats on water, so spraying water onto a fuel fire can actually spread it. However, water is the base for foam solution and is used in huge quantities.

AFFF (Aqueous Film-Forming Foam)

AFFF is the primary extinguishing agent for aviation fuel fires. When mixed with water and discharged, it forms a thin aqueous film that spreads across the surface of burning fuel, cutting off the oxygen supply and suppressing the fire. The foam also has a cooling effect and prevents re-ignition.

AFFF has been the industry standard for decades, but it contains PFAS (per- and polyfluoroalkyl substances) — so-called "forever chemicals" that persist in the environment and contaminate groundwater. This is a major issue for airports worldwide, and the industry is actively transitioning to fluorine-free foams (FFF). More on this in a later lesson.

Dry Chemical Powder (DCP)

Potassium bicarbonate or sodium bicarbonate powder is carried as a complementary agent. It is particularly effective at knocking down flames rapidly (faster than foam in some situations) and is used for:

• Three-dimensional fires (fuel flowing or spraying, such as from a ruptured fuel line)
• Engine fires
• Wheel and brake fires
• Small localised fires where foam would be excessive

DCP works by chemically interrupting the combustion reaction. However, it has no cooling effect and does not prevent re-ignition, so it is always backed up by foam.

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Performance Requirements

ICAO and the UK CAA set strict performance requirements for airport fire vehicles:

Response Time

• The first vehicle must reach any point on the operational runway within two minutes of being called
• The remaining vehicles must arrive within three minutes
• This is measured from the time the alarm sounds in the fire station

At Prestwick, the fire station's location on the airfield ensures these response times can be met for both runways.

Discharge Rate

The discharge rate must be sufficient to cover the critical area around the aircraft — the area that must be kept fire-free to allow evacuation. The required rates depend on the airport's RFFS category:

Prestwick's Category A7 requires at least 12,100 litres of water and a combined discharge rate of at least 5,300 litres per minute from all vehicles. When operating at Category 8 or 9 (for larger aircraft), significantly more water and higher discharge rates are needed — this is achieved by deploying additional vehicles.

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Acceleration and Terrain Performance

Airport fire vehicles must be able to reach high speeds quickly on the flat paved surfaces of taxiways, but also maintain performance on the grass, soft ground, or rough terrain surrounding the runway. This is why:

• All-wheel drive is standard (6x6 or 8x8 configurations)
• Vehicles have automatic transmissions optimised for rapid acceleration
• Tyre pressures may be adjustable for different surfaces (a system called CTIS — Central Tyre Inflation System)
• Vehicles are tested to achieve 80 km/h within specific distances on dry pavement

The combination of massive weight (a fully loaded MFT can weigh over 40 tonnes), high speed capability, and off-road performance makes these extraordinary engineering achievements.

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Crew Cab and Survivability

The crew cab of an airport fire vehicle is designed to protect the crew in extreme conditions:

• Heat-resistant construction to protect against radiant heat from a fuel fire
• Air filtration to keep toxic fumes out
• Pressurised cab to prevent smoke ingress
• 360-degree visibility with heated windows to prevent misting
• Intercom systems to allow communication over the noise of the engine and fire
• Roof turret controls inside the cab, allowing the driver or co-driver to aim and discharge foam while still in the vehicle

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Maintenance

Every fire vehicle undergoes rigorous daily checks and regular maintenance:

• Daily: Water and foam levels checked, engine started, lights and sirens tested, pumps cycled, rescue equipment checked
• Weekly/Monthly: Foam concentration tested, hose integrity checked, mechanical components serviced
• Annual: Full inspection and certification

A fire vehicle that is out of service affects the airport's RFFS category. If the airport cannot meet the minimum vehicle requirements for its declared category, the category must be reduced — and if it drops too far, certain aircraft may not be able to operate until the vehicle is returned to service.

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Spotting Fire Vehicles at Prestwick

If you are watching aircraft at Prestwick, you may occasionally see the fire vehicles:

• During training exercises — you might see foam being applied on the training ground
• During a standby — vehicles positioned alongside the runway with flashing lights as an aircraft with a declared emergency approaches
• During routine runway inspections — a fire vehicle sometimes accompanies the airfield inspection run
• During taxiway operations — fire vehicles may escort wide-body cargo aircraft during special operations

They are unmistakable — much larger and more aggressively styled than anything on the public roads, painted in high-visibility colours, and equipped with an array of lights and monitors that make them look like something from a science fiction film.