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Title:
FIRE FIGHTING DEVICE FOR HELICOPTERS
Document Type and Number:
WIPO Patent Application WO/2011/154325
Kind Code:
A1
Abstract:
Fire fighting device (1) designed to be fixed under a helicopter (50), said helicopter having landing gear (51) and an external load hook (58), said fire fighting device comprising a frame (2), a fluid reservoir (4), an adjustable fluid spraying organ (3), housings (5) adapted to receive portions of landing gear, an attachment device (6) adapted to be connected to the external load hook (58) using a traction cable (20) and a hoist (21), such that the fire fighting device (1) can be fixed under the helicopter landing gear, such that said fire fighting device (1) may be rigidly installed under any helicopter without modification to the helicopter.

Inventors:
DE LASSUS REGIS (FR)
DANIELS STEVENS (US)
Application Number:
PCT/EP2011/059228
Publication Date:
December 15, 2011
Filing Date:
June 03, 2011
Export Citation:
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Assignee:
DE LASSUS REGIS (FR)
DANIELS STEVENS (US)
International Classes:
B64D1/16; B64D1/22
Foreign References:
US4589614A1986-05-20
US4993665A1991-02-19
US3714987A1973-02-06
US20060175429A12006-08-10
Attorney, Agent or Firm:
PRIEUR, Patrick et al. (52 rue de la Victoire, Paris Cedex 09, FR)
Download PDF:
Claims:
CLAIMS

1. Fire fighting device (1) designed to be fixed under a helicopter (50), said helicopter having landing gear (51) and an external load hook (58), said fire fighting device being designed to be fixed under said landing gear (51), and comprising:

- a frame ( 2 ) ,

- at least one fluid reservoir (4) fixed to the frame, - a fluid spraying organ (3) fixed to the frame, designed to pro ect /spray the fluid along a spraying direction (P) ,

- at least two housings (5) each adapted to receive at least one landing gear portion,

- an attachment device (6) located approximately above the centre of gravity of the fire fighting device, adapted to be connected to the external load hook (58) using a traction cable (20) and a hoist (21), such that said fire fighting device (1) can be fixed in place under the helicopter landing gear when said landing gear fits into said housings and when the traction cable (20) is tensioned,

in which said housings (5) are dished with the recess facing upwards, said shape being adapted to receive the wheels (56) of the landing gear (51),

whereby said fire fighting device (1) may be secured under a helicopter without any modification to the helicopter, and it can be jettisoned using the external load hook.

2. Fire fighting device (1) according to claim 1, in which said housings (5) also comprise at least one sensor

(71) adapted to detect the presence of a portion of landing gear in the housing.

3. Fire fighting device (1) according to one of the previous claims, in which said housings are provided with rollers (72) or roller bearings to facilitate positioning of said wheels.

4. Fire fighting device (1) according to one of the previous claims, further comprising stands (7), such that said helicopter fitted with the fire fighting device (1) can be landed on the ground on said stands.

5. Fire fighting device (1) according to one of the previous claims, further comprising the hoist (21) and the traction cable (20).

6. Fire fighting device (1) according to one of the previous claims, in which the hoist (21) comprises a force measurement sensor (26), such that the tension cable may be adjusted to firmly secure the device under the helicopter.

7. Fire fighting device (1) according to one of the previous claims, in which the hoist (21) comprises a locking device (25) that can prevent any hoist rotation, a locking sensor adapted to output a signal representative of the locked state of the locking device to light up a hoist locked indicating light (84) .

8. Fire fighting device (1) according to one of the previous claims, further comprising a control unit (60) adapted to control starting and/or stopping fluid spraying, said control unit being adapted so that it can be remotely controlled from the helicopter cockpit.

9. Fire fighting device (1) according to claim 8, further comprising an auxiliary remote control box (61) connected to said control unit so that an individual can remotely operate the fire fighting device (1) from the helicopter cockpit.

10. Fire fighting device (1) according to one of the previous claims, in which said attachment device (6) is located slightly aft from the centre of gravity of the fire fighting device, such that the fire fighting device (1) has a nose-down attitude when it is lifted.

11. Fire fighting device (1) according to one of the previous claims, comprising at least one compressed air foam system (43) adapted to generate a fire fighting fluid essentially based on foam.

12. Fire fighting device (1) according to one of the previous claims in which the frame is perforated, such that the fire fighting device has no lift and almost no impact on the aerodynamic performances of the helicopter.

13. Fire fighting device (1) according to one of the previous claims, in which the helicopter has a main rotor (54) and a longitudinal axis, the spraying organ is installed in a position that projects forwards from the rotor along the longitudinal axis, and in which the spraying organ (3) can be oriented and displaced by an orientation mechanism.

14. Fire fighting device (1) according to one of the previous claims, further comprising at least one electrical battery (8) capable of supplying electrical energy to at least the orientation mechanism and/or the hoist and/or the control unit and/or the sensors and/or the compressed air foam system, such that said fire fighting device (1) can operate autonomously.

15. Fire fighting device (1) according to one of the previous claims, further comprising at least one auxiliary electrical connector so that the fire fighting device (1) can be supplied with electrical energy on the ground from the electrical network.

16. Method to fix a fire fighting device under a helicopter, said helicopter having landing gear and an external load hook,

said fire fighting device comprising:

- a frame ( 2 ) ,

- a fluid spraying organ (3) fixed to the frame,

- at least one pressurised fluid reservoir (4) fixed to the frame,

- at least one housing (5) adapted to receive at least one landing gear portion,

- an attachment device (6) located approximately above the centre of gravity of the spraying device, adapted to be connected to the external load hook using a traction cable (20) and a hoist (21) ,

said method comprising the following steps:

- attach the cable to one of the ends chosen between the external load hook and the attachment device,

- wind the cable on the hoist to lift the fire fighting device, which takes on a nose-down attitude,

- put the aft landing gear portions into position in their aft housing and check the presence of the landing gear portions in the aft housings (5a),

- wind the cable onto the hoist such that the fire fighting device comes into contact with at least one portion of the forward landing gear, and that a portion of the forward landing gear fits into the forward housing (5b) ,

- tension the cable with a force greater than a predetermined threshold.

17. Fire fighting system comprising:

- at least two fire fighting devices (1) according to one of claims 1 to 15,

- a first lorry (101) adapted to transport at least two fire fighting devices (1),

- a second lorry (102) adapted to transport fluid replenishment means.

18. Fire fighting system comprising:

- at least one fire fighting device (1) according to one of claims 1 to 15, further comprising means of connection for connecting a hose,

- a lorry adapted to transport fluid replenishment means and comprising a fire fighting fluid preparation means ,

- a connecting hose comprising two ends, the first end being connected to said fire fighting fluid preparation means (43) the second end being connected to the connection means on the fire fighting device (1) .

Description:
FIRE FIGHTING DEVICE FOR HELICOPTERS

This invention relates to fire fighting devices for helicopters, particularly for fire fighting in a tall building.

More particularly it concerns a fire fighting device designed to be fixed under the landing gear of a helicopter, said helicopter having an external load hook, said fire fighting device comprising:

- a frame,

- at least one fluid reservoir fixed to the frame,

- a fluid spraying organ fixed to the frame, designed to project and spray the fluid along a spraying direction.

This type of fire fighting devices is well known, for example as disclosed in document US2006-0175429 that presents a system comprising a helicopter and a fluid container equipped with a spray gun. However, the teachings in this document state that it is difficult for the helicopter to approach the container so that the locking elements located under the helicopter can be positioned on the container locking hooks so that said container can be locked and secured, because the positioning tolerance of the helicopter relative to the container at the time of the attachment is almost non- existent, and this applies to the three axes (axial, longitudinal, vertical), making the manoeuvre very difficult for a pilot and even especially dangerous particularly in the case of even light air turbulence. Furthermore, the helicopter is obliged to hover a few centimetres above the container on the ground before the attachment manoeuvre can be performed, which is impossible for a pilot and is very dangerous.

Furthermore, the helicopter cannot land with this equipment secured under the cabin without risk of damage.

Modifications to the helicopter also have to be made to install the locking hooks.

Moreover, since in prior art the onboard device is installed between the different parts of the landing gear, the size of the onboard device is limited by the longitudinal and transverse wheel base of the landing gear.

Moreover, in prior art, there is neither a normal jettisoning function nor an emergency jettisoning function of the device.

In particular, this invention is intended to alleviate the disadvantages of prior art.

To achieve this, according to the invention, the fire fighting device comprises:

- at least two housings each adapted to receive at least one landing gear portion,

- an attachment device located approximately above the centre of gravity of the spraying device, adapted to be connected to the external load hook using a traction cable and a hoist, such that said fire fighting device can be fixed in place under the helicopter landing gear when the landing gear fits into said housings and when the traction cable is tensioned, wherein said housings are dished with the recess facing upwards, said shape being adapted to receive the wheels of the landing gear.

Thanks to these arrangements, said fire fighting device may be secured under any helicopter without any modification to the helicopter.

One or more of the following arrangements can be used in the different embodiments of the invention:

- said housings may also comprise at least one sensor adapted to detect the presence of a portion of landing gear in the housing; the helicopter pilot can thus be assured that the safely secured position is adopted;

- said housings may be being provided with rollers or roller bearings to facilitate positioning of said wheels; this facilitates positioning as the device approaches the landing gear; - the device may also comprise stands, such that said helicopter fitted with the fire fighting device can be landed on the ground on said stands;

- the device 1 may also comprise the hoist and the traction cable, which in this case are integrated into the device ;

- the hoist may comprise a force measurement sensor, such that the tension cable may be adjusted to firmly secure the device under the helicopter;

- the hoist may comprise a locking device that can prevent any hoist rotation, a locking sensor adapted to output a signal representative of the locked state of the locking device to light up a hoist locked indicating light; this prevents any inadvertent rotation of the hoist;

- the device may also comprise a control unit arranged to control at least starting and/or stopping fluid spraying, said control unit being adapted so that it can be remote controlled from the helicopter cockpit.

- said device may also comprise an auxiliary remote control box connected to said control unit so that an individual can remote operate the fire fighting device from the helicopter cockpit;

- said attachment device may be located slightly aft from the centre of gravity of the fire fighting device, such that the fire fighting device has a nose-down attitude when it is lifted;

- said device may comprise at least one compressed air foam system adapted to generate a fire fighting fluid essentially based on foam;

- the frame may be perforated, such that the fire fighting device has no lift and almost no impact on the aerodynamic performances of the helicopter;

- since the helicopter has a main rotor and a longitudinal axis, the spraying organ is installed in a position that projects forwards from the rotor along the longitudinal axis, and the spraying organ can be oriented and displaced by an orientation mechanism;

- said device also comprises at least one electrical battery capable of supplying electrical energy to at least the orientation mechanism and/or the hoist and/or the control unit and/or the sensors and/or the compressed air foam system, such that said fire fighting device can operate independently;

- said device also comprises at least one auxiliary electrical connector so that the fire fighting device can be supplied with electrical energy on the ground from the electrical network,

- said device comprises a wind speed and direction sensor close to the spraying organ.

The invention also relates to a method to fix a fire fighting device like that described above,

said method comprising the following steps:

- attach the cable to one of the ends chosen between the external load hook and the attachment device,

- wind the cable on the hoist to lift the fire fighting device, which takes on a nose-down attitude,

- put the aft landing gear portions into position in their aft housing and check the presence of the landing gear portions in the aft housings,

- wind the cable onto the hoist such that the fire fighting device comes into contact with at least one portion of the forward landing gear, and that a portion of the forward landing gear fits into the forward housing,

- tension the cable with a force greater than a predetermined threshold.

The invention also relates to a fire fighting system comprising :

- at least two fire fighting devices like those described above,

- a first lorry adapted to transport at least two fire fighting devices,

- a second lorry adapted to transport fluid replenishment means.

Finally the invention also relates to a fire fighting system comprising:

- at least one fire fighting device like that described above, also comprising means of connection to a connecting hose,

- a lorry adapted to transport fluid replenishment means and comprising a fire fighting fluid preparation means ,

- a connecting hose comprising two ends, the first end being connected to said fire fighting fluid preparation means, the second end being connected to the connection means on the fire fighting device.

Other aspects, purposes and advantages of the invention will become clear after reading the following description of one of its embodiments, given as a non-limitative example. The invention will also be better understood with reference to the appended drawings among which:

- figure 1 is a schematic side view of a helicopter equipped with a fire fighting device according to the invention,

- figure 2 is a front view of the helicopter equipped with the fire fighting device of figure 1,

- figure 3 is a perspective view of the fire fighting device of figure 1,

- figure 4 is a top view of the fire fighting device of figure 1,

- figure 5 is a side view of the fire fighting device of figure 1 with a partial cut out,

- figure 6 is a perspective bottom view of the fire fighting device of figure 1 secured under the helicopter,

- figure 7 is a diagram showing the control unit, the sensors, the actuators and the remote control box of the fire fighting device of figure 1,

- figure 8 is a perspective view of the adjustable spraying organ of the fire fighting device of figure 1,

- figure 9 is a sectional view of a housing of the fire fighting device of figure 1 into which a landing gear with wheels fits,

- figure 10 is a side view similar to figure 1 showing the nose-down attitude,

- figure 11 shows the lorries associated with the fire fighting device of figure 1,

- figure 12 is a side view similar to figure 1, showing a variant of the invention,

- figure 13 is a front view similar to figure 2, showing the variant of the invention of figure 12,

- figure 14 is a detailed view of a housing and a portion of landing gear according to the variant shown in figures 12 and 13.

The same references on the different figures denote identical or similar elements.

Figure 1 shows a schematic side view of a helicopter 50 equipped with a fire fighting device 1 according to the invention. The fire fighting device 1 is shown in solid lines in the secured position under the helicopter in which it is used to fight a fire, while the fire fighting device shown in chained dotted lines remains on the ground in the position prior to its installation under the helicopter and/or after it has been put down by the helicopter.

The helicopter has a longitudinal axis X, a transverse axis Y, the vertical axis Z being perpendicular to the two above-mentioned X and Y axes. As is well known in standard practice, the helicopter comprises at least one main rotor 54 approximately perpendicular to the vertical axis Z, this rotor defining a rotor disk and a rotor flux supporting the helicopter in flight. The helicopter also conventionally comprises landing gear 51 and an external load hook 58 located under the cabin approximately vertically below the centre of thrust as is known in standard practice.

With reference to figures 1 to 6, the fire fighting device 1 comprises a frame 2 that forms the support structure for equipment onboard the fire fighting device 1, this frame comprising a main body 2a extending under the helicopter cabin and a boom 2b extending forwards along the longitudinal axis X, and a forward end 2c of the boom that may project beyond the rotor flux swept by the rotor disk. A fluid spraying organ 3 in the form of a spray nozzle (sometimes also called 'gun') is attached, fixedly or adjustably, near the top of the forward end 2c of the boom 2b, arranged to spray the fluid along a spray direction P, the spray direction possibly being adjustable as will be described in detail later.

Furthermore, the fire fighting device 1 comprises stands 7 fixed under the main body 2a of the frame 2 (there are three of these stands in the example shown, but there are not necessarily three) . When the fire fighting device is on the ground, it is supported on said stands 7. Furthermore, when the fire fighting device is secured under the helicopter, the helicopter can land on the ground with the fire fighting device 1 secured under its landing gear 51, the stands and the frame being sized to be sufficiently robust to resist forces related to the weight of the helicopter.

Furthermore, the fire fighting device 1 comprises at least one fluid reservoir 4 used for fire fighting. In the example shown, the fire fighting device 1 is equipped with four large capacity reservoirs 41, for example 500 litres each, and four smaller reservoirs 42, for example 80 litres each. The reservoirs are preferably pressurised, and their content will be described in detail later. Preparation means 43 for mixing and preparing the fluid to be sprayed starting from the content of the reservoirs are also installed in the fire fighting device 1 and will be described in detail later.

The fire fighting device 1 also comprises at least two housings 5 each implemented to receive at least one landing gear portion 51.

In the example shown, the fire fighting device 1 comprises three housings 5 corresponding to the aft main landing gear 5a and the forward auxiliary landing gear 5d of a wheeled landing gear. Note that the invention is equally applicable to a forward main landing gear, with a tail roller as auxiliary landing gear.

The fire fighting device 1 also comprises at least one attachment device 6 located approximately above the centre of gravity of the fire fighting device 1, the attachment device 6 being arranged to be connected to the external load hook 58 through a connection. A hoisting arrangement is used to extend or shorten said connection. In the example shown in the figures, the hoisting device is onboard the fire fighting device 1 and it comprises a hoist 21 associated with a traction cable 20 forming the attachment device 6.

In one variant not shown, the hoisting arrangement comprises a hoist and an associated cable onboard the helicopter, and in this case the attachment device 6 on the device 1 is very simple and consists of a single hook or cleat perforated with a lifting hole.

Thus, said fire fighting device 1 may be fixed under the landing gear 51 of the helicopter when said landing gear fits into said housings 5 and when the traction cable 20 is tensioned by the hoist 21.

Advantageously, according to the invention, the fire fighting device 1 may be secured under any helicopter without any substantial modification to the helicopter, provided that it is fitted with an external load hook.

The hoist is preferably fitted into a casing 22 that forms part of the main body 2a of the frame.

The hoist 21 may also be equipped with:

- a locking pin 25 that secures the normal position of the hoist, that has to be released to authorise rotation of the hoist drum, a locking sensor 24 providing information that the hoist is properly locked and that all rotation is prevented,

- a force sensor 26 capable of measuring the force applied by the hoist on the cable, and transmitting this information.

The hoist has its own energy source, for example like an electrical battery 8 forming part of the device, this energy source also possibly supplying power to the fire fighting device including its gun and various equipment.

According to one advantageous aspect of the invention, said attachment device 6 is located above but also slightly rearward the centre of gravity of the fire fighting device, such that the fire fighting device 1 has a nose-down attitude when it is lifted, as shown in figure 10.

It is also considered that the external load hook 58 can be released under tension such that the helicopter can jettison the fire fighting device 1 instantaneously in case of emergency.

The frame 2 is preferably perforated so that it has no lift and so that the device can drop vertically in case it is jettisoned, without any pivot or rotation effect at the time of separation from the helicopter. In the example shown, the main body 2a is constructed using a welded light alloy with a horizontal ' T ' shape, with a plurality of openings 2d. The boom 2b has generally a square or triangular section, which reduces towards the distal end 2c to which the spraying organ 3 is fixed.

The frame 2 is preferably a single piece so as to minimise the risk of detachment of a part that might drop or hit the blades of the helicopter.

Furthermore, the fire fighting device 1 may also comprise a control unit 60 designed to start and/or stop fluid spraying, using a solenoid valve 31 located close to the spraying organ or at the exit from the preparation means 43 for the fluid to be sprayed. The control unit 60 may also control orientation of the spraying organ, the hoist control 21 and the different safety controls. More precisely, said control unit 60 comprises an output 31a to energize the solenoid valve 31 starting fluid spraying, outputs 21a, 21b to control the motor 28 of the hoist 21 in the two directions of rotation (cable retraction and extension) and an output 25a to control the locking/unlocking pin 25 of the hoist mentioned above.

The control unit 60 also comprises a positive power supply 8a and a ground connection 8b, and inputs, particularly :

- one or several inputs 71a to acquire signals from the presence sensors 71 sensing the presence of the portions of landing gear,

- an input 24a for the position of the locking pin 25,

- an input 26a to acquire the signal from the force sensor 26 that measures the force applied by the hoist.

Optionally, the control unit 60 may comprise one or several outputs that will cause fast draining of the content of the reservoirs 40, 41 using a drain solenoid valve 90 and an input 91 to acquire the wind speed and direction at the end of the boom.

Said control unit 60 is arranged to be remote controlled from the helicopter cockpit using an auxiliary remote control box 61 that comprises:

- three light indicators 81, 82, 83 reporting the presence of a portion of landing gear in the different housings 5,

- a joystick 85 controlling the mechanism of orientation of the spraying organ 3,

- a fluid spray start trigger 86,

- a fast reservoir draining control button 89,

- various instrumentation such as the level of the fluid reservoirs (94, 95), a wind indicator at the gun 93, a battery charge level indicator (not shown) .

When the hoist 21 is integrated into the device, the box also comprises:

- a hoist retraction (winding in) or extension (winding out) control lever 87, - a hoist unlocking control button 88,

- a hoist locking light indicator 84.

The remote control box 61 is connected to a control unit 60 through a connection 62 that in the example shown is a wireless connection using radio frequency waves. However, a wire connection could also be used.

Figure 8 shows a detailed view of the spraying organ 3 comprising a fluid inlet 36, an internal duct 32 that can be oriented along an azimuth direction (angle a) and an elevation direction (angle β ) , and an outlet 33 aligned on the spray direction P. Advantageously, according to the invention, the elevation angle β is limited by a high stop to a predetermined value max such that it is impossible for the fluid jet to interfere with the blades of the rotor 54. Orientation mechanism, that in the example shown are electric motors 35, 37 enable to displace the outlet to the required azimuth and elevation angles. These motors 35, 37 are controlled from the joystick 85 of the remote control box 61 through the control unit 60 and its outputs 35a, 37a. There is also a wind speed and direction sensor 92 installed at the end of the boom. The fluid spray may be disabled if the headwind is too strong making spraying too dangerous .

Figure 9 shows a detailed view of one of the housings 5 designed to contain a portion of the landing gear 51, in the shown example a wheel 56 or a double wheel. The housing is dished with a recess facing upwards, said housing preferably being provided with rollers 72 or roller bearings that facilitate positioning of said wheels 56 when the fire fighting device 1 is lifted towards the helicopter and the housing comes into contact with the wheels, thus enabling the wheels to fit into the housing with a relative positioning tolerance between the hovering helicopter and the fire fighting device 1. A presence sensor 71, for example installed at the bottom of the wheel reception area, provides information reflecting the presence of the wheel 56 or the double wheel inside the housing 5. The preparation means 43 for the fluid to be sprayed (also called "generator") are installed in the main body 2a of the fire fighting device 1 and are not shown in detail. For example, these means comprise a pump, an emulsifier, a mixing chamber and a regulator as is well known in prior art. Preferably, a water-based solution contained in the large reservoirs 41 is mixed with a compressed gas contained in the small reservoirs 42, for example in the ratio of 1 volume of water for 7 volumes of air, to obtain a light foam mix that is particularly efficient for fire fighting. This mix is called OAFS' (Compressed Air Foam System) in the field. The invention is in no way limited to a particular mix, and any solution similar to CAFS could be envisaged within the framework of this invention.

The invention also relates to a method to fix a fire fighting device 1 under a helicopter when the helicopter is hovering a few metres above the device (which is on ground) . The method comprises the following steps:

- attach the cable 20 to one of the ends chosen between the external load hook 58 and the attachment device 6,

- wind the cable 20 onto the hoist 21 to lift the fire fighting device 1, which moves into a nose-down attitude, the forward end of the boom possibly being held by an operator on the ground to guide the aft part relative to the aft landing gear,

- put the landing gear portions into position in their housing and check the presence of the landing gear portions in the aft housings 5a,

- wind the cable 20 onto the hoist 21 such that the fire fighting device 1 comes into contact with the forward landing gear, and that a portion of the forward landing gear fits into the forward housing 5b,

- tension the cable to a force exceeding a predetermined threshold, the control unit 60 stopping the control of the motor 28 of the hoist as soon as the force measured by the sensor 26 exceeds this predetermined threshold . In this way, the fire fighting device is secured under the helicopter by a robust attachment. Furthermore, the hoist 21 is locked by the locking pin 25 which secures the attachment .

According to one variant of the embodiment described above, the fire fighting device 1 can also be adapted to skis as shown in Figure 12, 13 and 14.

In this variant, the housings 5 are in the form of channel extending along the longitudinal X axis with a V section open upwards as shown in Figure 14, with edges 53 and a bottom 54. The skis 51 forming the landing gear have a tubular section 510 that can fit into the V shape. A flexible material element 52 fixed to the bottom 54 of the housing 5 is inserted between the tubular section 510 and said bottom 54 to prevent relative movement along the longitudinal X axis. The presence sensor 71 similar to that described above is installed at the bottom of the element made of a flexible material 52.

Another aspect of the invention described with reference to figure 11 discloses a fire fighting system comprising :

- at least two fire fighting devices 1 as described above,

- a first lorry 101 adapted to transport at least two fire fighting devices 1,

- a second lorry 102 adapted to transport the fluid supply means .

Advantageously according to the invention, the ease of picking up and putting down the fire fighting device makes continuous intervention by helicopter possible provided that two fire fighting devices are used in rotation. While one helicopter is using a fire fighting device to work on a tall building, the other is on the ground and can be replenished with water and compressed air from the second replenishment lorry 102.

The first lorry 101 can quickly move the two fire fighting devices to a site on which a helicopter can land close to the fire while the helicopter also moves to the site .

According to another variant of the embodiment described above (not shown in the figures), the fire fighting device 1 may comprise means of connection to a connecting hose adapted to connect the fire fighting device 1 to a device on the ground through said connecting hose. Under these conditions, the fire fighting system comprises:

- one or several fire fighting devices 1 as described above,

- a lorry adapted to transport the fluid replenishment means and comprising means of preparing a fire fighting fluid,

- the connecting hose that comprises two ends, the first end being connected to said fire fighting fluid preparation means, the second end being connected to the connection of the fire fighting device 1.

Note that without going outside the framework of the invention, some helicopters may be fitted with an external electrical power outlet, the fire fighting device could be connected to this power outlet so that a choice could be made between a lower capacity onboard battery, or possibly it could be decided not to use a battery at all which has the advantage of reducing the weight of the fire fighting device.

Similarly, some helicopters could be pre-equipped with a compressed air outlet designed for use by some external equipment, and in such a case the fire fighting device could be simplified so that it only carries the liquid, and in this case the fire fighting device uses pressurised air from the helicopter.

Note that a flat strap could be used instead of the cable 20, without going outside the framework of the invention .