jc:
good question - youre not from NSW in Oz are you??
In NSW, they though for many years that 10 X 206s were the answer despite the rest of the world operating larger machines, and now they have a completely opposite view - only big machines!
IMHO, the truth is somewhere in between - different machines offer different capabilities. Although 9 AS350s seem like a good idea, they will be unable to put anywhere near the same amount of water on a fire as one AirCrane, nor will they be able to do it for less cents per litre in operating costs. But probably the most important reason is that the larger volume of water when dropped in one hit has a vastly greater effect than the same amount of water dropped in 9 seperate drops. This is entirely due to the turbulance and heat of the fire dissapating smaller drops, and only allowing larger volumes to penetrate into the fire front. In fact in larger fires, an AS350 drop may be entirely useless (apart from the revenue it is earning!
)
BUT - have a minor unserviceability with your one Crane, and you have lost all capability, where as one 350 down means 8 more to deliver water. This is why I said that the truth is "somewhere in between". Having both on hand is the answer.
There are some other aspects of employing a variety of machines that I posted in another thread in response to news that NSW were going to get rid of buckets under smaller machines (unlike the rest of the world - again!). Read this if you are intrested:
Page 2 has the info