Aerial Firefighting

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Contents
Aerial Patrol
Fixed Wing Water Bombing
Helicopter Water Bombing
Aerial Delivery of Firefighters
Other Aerial Firefighting Tasks

Aerial Patrol

A fixed-wing plane was first used for reconnaissance at the Eyrewell Forest fire in 19403. Planes were first routinely used1 for fire patrol duties in the Rotorua district in 1943. Early in 1944, very dry conditions prevailed, and the haze and smoke caused assessment difficulties.  The air force was requested to provide a plane for general patrol duties, and an Oxford, later replaced by a Havard, was assigned for this purpose. It was based at Rotorua Airport, and flew with a Forest Service officer as observer.  At this stage, there was no radio on board that could communicate with Kaiangaroa Forest HQ, and reports were telephoned after landing.

Nevertheless, this trial was promising, and next season (1944/45) the RNZAF made an Oxford available at Rukuhia Aerodrome available for patrols. This was equipped with a SCR274 HF radio, and could talk to Kaingagora. Some 30 hours were flown, and valuable experience was gained. It proved that the Oxford was not ideal, use of RNZAF radio frequencies caused problems, and the plane needed to be based locally for rapid despatch.

For the 1945/46 season2, the RNZAF formed a special flight as part of No. 42 squadron, and assigned two aircraft: a DH Fox Moth and a canopy DH Tiger Moth, both equipped with SCR183 radios.  The Fox Moth was to be the patrol aircraft, with the Tiger Moth as backup. The RNZAF detachment took uo station at Rotorua on 15 October 1945. The personnel lived in single-man huts provided by the Forest Service, and meals were provided by the Geyser hotel at 3 per man per week. Hangarage was a problem,; this was to be provided by the Forest Service, but work on it did not begin until mid November. Space was found in another hanger, helped by the Fox Moth fitting in snugly on account of its folding wings. The Tiger Moth remained in Rongatai, as had been the intention.

In the first 5 weeks, the Fox Moth flew about 25 hours on 32 sorties, and more than 25 fire reports were made. While away on maintenance for a week at the end of November, the Tiger Moth substituted. It was found that the canopy restricted visibility, but it was used extensively until it nosed over with a wind gust after a landing at Taupo on 10 February 1946. 

The devastating Taupo fire started on 9 February 1946. A Havard augmented the Fox Moth, and both pilots were very

Taupo fire,  1946

 busy. Usually, one was stationed on the Kaiangaroa strip and the other at the Taupo airfield. The observers like the Havard; it was 50% faster in speed, had longer flight times and could fly in most wind conditions. On the second day of the fire, Flight Lieutenant Fred Ladd (1908-1989) was flying the Havard with a National Film Unit cameraman (see right) on board. The plane's engine spluttered out 300 m from the flames. Fortunately, it restarted just in time for Ladd to be able to power away from danger, and make his mark as a famous aviator in the Auckland region (the NFU film clip makes no mention of this!).

During the emergency, planes were used almost daily to mount patrols around the whole forest area at 11am, 2pm and 4:30 pm1. It was found that early morning observations could be misleading when assessing the day's potential fire behaviour. The observer would advise ground crews fully informed of progress along the whole of the front, adding to their safety. They were also able to better direct resources to problem areas. In one sector, the Boss requested an additional 50 men, but the observer countermanded this, and was proven correst in his assessment. The planes could also mark the best routes for firebreak creation to the ground crews by flying the optimum lines. At the end of the season, over 200 hours had been flown, and the charge for the service was 250 per month plus 2 per aircraft flying hour. The value of aerial patrols had been proven.

The RNZAF resumed patrols in the 1946/47 using the Fox Moth and two Tiger Moths, with a third Tiger Moth in reserve. The Fox was sold to National Airways Corporation in July 1948 for 1200, went through 10 New Zealand owners, and was exported to the UK. It was still flying in 1993.

Fixed Wing Water Bombing

Following the Second World War, there were plenty of ex-military pilots and planes. Aerial top dressing of fertiliser became established in New Zealand's rural areas. A newspaper article claimed that the first water bombing trials in the South Island were carried out at Lincoln on 31 January 1956. The trials were sponsored by the Soil Conservation and Rivers Control Council with the co-operation of Canterbury Agriculture College. Simulation fires were lit in a fallowed paddock at the college, and two aircraft from Auster Air Services Ltd flew from an adjacent paddock. The fires were in straw and pine branches, laced with diesel, and there was a light wind. One of the planes was a Taylorcraft (360 litres water load), and the other was a Tiger Moth (180 litres). The aerial attacks were not quite as effective as had been hoped. Most of the observers thought that the use of aircraft had possibilities, but there was a lot to learn.

A memorandum to the Minister of Forests from the Director General of the NZ Forest Service AL Poole on 17 April 1970 reviewed water bombing trials over the previous 15 years. The memorandum had probably been prompted by an aerial attack at a Silverstream fire on 6 March that year. Canadians had also been demonstrating a water bomber in Australia early in 1970. The NZ Forest Service had conducted experiments in conjunction with the Soil Conservation and Rivers Control Council between 1956 and 1959. A report by AR Entrican (then DG) and ER Blake in 1960 effectively squashed all local enthusiasts at that time. Due to a shortage of work during the temporary recession in 1968, air companies endeavoured to revive interest, and the Forest Service made further experiments with a DC3 in Palmerston North in 1968, and with Piper aircraft at Golden downs Forest in 1969. Both proved as ineffectual as previous trials.

During the 1969-70 fire season, Ad Astra Aviation Ltd (Tauranga) and Air Contracts Ltd (Pahiatua) had been promoting aerial water bombing to metropolitan, urban and county fire authorities. Forest Service Fire Control Officers had only been able to evaluate the efforts at the Silverstream (Hutt County) fire on 6 March. One officer was working on the fireline directly below the 900 litre drops. He claimed that each drop was like gentle rain over a 10 to 17 second period, and had no effect on the fire whatsoever. This was in contrast to the fulsome publicity given to the bombing. The officer's small crew were the only firefighters anywhere near the fire which was most lazy, and could have been dealt with several men using shovels in an afternoon. The memorandum concluded that extravagant claims were being made of the effectiveness of water bombing.

The promotion of fixed wing water bombing continued. In a telex to Conservancies, dated 17 January 1979, the Chief Fire Control Officer, Bill Girling-Butcher stated that 'we have proved that small loads are ineffectual and large loads wasteful'. He added that in 1976, the Forest Service endeavoured to set up a 7000 litre modular system in which the load is pressurised to prevent slipstream erosion of the drop, but Defence declined the use of a Hercules aircraft. Nevertheless, the air companies persisted, and limited use is made of small agricultural-type planes, such as the Cresco, in parts of the country to drop water and additives. This is in contrast to Canada and Europe where Canadair float planes are a significant firefighting resource, or the US where jet tanker planes as big as DC10's (45,000 litre loads) and Boeing 747's (80,000 litre) are available.

Helicopter Water Bombing

The 1970 Ministerial memorandum stated that Forest Service 'Officers on the Water Bombing Mission to Canada in 1969 were most impressed with the use of fibre glass "Monsoon Buckets" attached to helicopters which far surpassed our tests made earlier that year in Nelson with canvas equipment'. One bucket was imported, cost $670, and 'trials recently completed were faultless'. Drops of up to 540 litres would be possible to provide a sustained penetration dump below a hovering machine. 'Turn-around is much quicker, loading is instantaneous, and costs are similar to those for fixed wing aircraft which are charged out at $100 an hour'. A firm in Taupo was contracted to manufacture a prototype bucket that would be cheaper.

The adoption of helicopters for aerial firefighting fortuitously coincided with their use in the lucrative business of deer recovery. The result was that New Zealand has the highest number per capita of helicopters of any country in the world. The early helicopters used were small with limited load capacity , but sufficient for the 500 litre buckets. Only the Air Force had Iriquois - Hueys of the Vietnam war -  capable of  loads up to 1800 litres, and these were  occasionally used at fires. But the bulk of aerial firefighting was, and is, done on contract by private companies. Environmental logging saw the introduction of heavier machines such as the Bell Iriquois UH1 and Russian Mil Mi-8, but Bell 206 Jetrangers, Eurocopter AS350BA  Squirrels (600 l capacity) and Eurocopter BK-117's (1,000 l) are the common types used for firefighting. The larger machines facilitated a development in buckets with greater capacities. The air-operated fibre glass buckets (BA cylinders had to be carried to drive the solenoid plunger) have given way to electrically-operated collapsible fabric buckets. The use of fabric reflects the original intent of the Forest Service in 1969. These days, buckets are usually either the Dew Drop (maximum capacity 900 litres) developed by the Forest Serice/DOC, Aflex or the  Bambi. A video of the Aflex is available. Modern buckets can be compressed or folded for easy cartage by the responding helicopter, along with onboard Class A foam injection equipment. Buckets and foam equipment are generally owned by the helicopter companies, and sized appropriate to the helicopters supplied. Of course, costs have escalated far beyond the 1970 '$100 an hour'! A 1996  study by fire researchers  of the Forestry Research Institute showed that 'bigger was better' in terms of $cost/litre delivered. The researchers undertook several trial projects throughout 1996/97 to provide guidelines in the use of helicopter water bombing.

Aerial Delivery of Firefighters

Unlike US smokejumpers, the use of parachutes and fixed wing aircraft to deliver firefighters to remote fires was never adopted in New Zealand. There are reports of the use of planes to deliver firefighters and their equipment to remote landing sites in 1945/462. Helicopters are frequently used for transport on firegrounds, and all rural firefighters are required to undergo helicopter safety training. They are generally landed, or dismount with the helicopter in a low hover. Only one rural fire authority, Wellington, has a trained firefighting team to rapell into remote areas ('rapattack' or 'helitack'). While expensive, the action can provide a rapid ground attack. The drawback can be a long walk to road transport to get home! 

Other Aerial Firefighting Tasks

A helipcopter is a versatile tool for firefighting, and is employed for a variety of tasks. Mapping fires and checking for heat spots with infrared cameras at large fires is usual. Small helicopters are often used in the air to co-ordinate the operations of heavier ones when they are attacking with water drops - the american term is 'bird dogging'. Incendiary devices can be underslung to start burnoffs for land clearing, or to burn out from a fire break in advance of a fire front. As Don Geddes pointed out, such actions are not for the faint-hearted as the results of rapidly laying down a line of fire tend to be rather spectacular. These practices have become rare because burning to clear slash from cutover forest, or clearing land for new forest, is seldom used in this country. These skills are being lost. Similarly, few will have witnessed the amazing effectiveness when burning out in front of an impending front. Overseas deployments of firefighters are redressing the loss of these skills.

Supporting ground crews from the air with additional supplies such as hose packs adds to overall effectiveness, and is commonly done. Right from the introduction of helipcopters, attempts were made to use them to quickly lay out hose from packs held in the cockpit. The rotor wash made this difficult, and potentially hazardous to the helicopter. The adjacent photo shows Ian Millman attempting this in the early 1970's; the hose go wrapped around the skid of the chopper. The Forest Service solved this problem by connecting 6 packs of flaked hose in an underslung wooden box ('coffin'). This enabled 540 m of hose line to be quickly laid out, often over inhospitable terrain. Unfortunately, ground crews usually had to recover this!   

 

References
1. FJ Perham, NZ Journal of Forestry. V: 219. 1946.
2. C Jenks, RNZAF Insight and The Rural Firefighter, Feb. 1993.
3. ME Alexander, FRFANZ Conference, 1999.