THE Victorian Government's multi-million dollar investment in an American firebombing air tanker was put to the test for the first time in Australian conditions near Trentham yesterday.The 45,000-litre capacity aircraft, based at Avalon airport near Geelong for the duration of the fire season, was leased by the Government from the Californian Government to bolster firefighting efforts.Yesterday, the former passenger aircraft released 42,000 litres of fire retardant over a 1.2-km stretch of bushland near Trentham to gauge its effectiveness in fighting blazes in the Australian bush."(It's) about testing how appropriate it is to be used in Australian conditions and how effectively the water released penetrates the tree canopy," Bushfire Cooperative Research Centre chief executive officer Gary Morgan said."It has been used in America for nearly three years but mainly to fight shrub and grass fires."It is important we take time to fully understand its capabilities and its limitations under Australian conditions."Yesterday's exercise was the first of a number planned in different Victorian terrain and conditions, which would determine if the Victorian Government will continue to lease it to aid their firefighting resources in subsequent years.Bushfire CRC researchers moved in to examine the site soon after the 3.15pm drop yesterday, while five other aircraft monitored other aspects, such as the drift of the retardant and and the shape as it dropped.Mr Morgan said it would be a long process to determine its effectiveness."It penetrated the canopy but the question is how well, how far and just how effectively, we certainly need a bit more time to gather that information," he said."It won't be done in isolation it will be a matter of pulling all the data together."A second trial drop is planned in grassland at Avalon today.More than 100 CFA, DSE and Parks Victoria workers were on the ground at the trial site.CFA operations manager Stephen Walls said he was pleased with the smooth operation of the trial, despite the aircraft dropping the retardant more than an hour later than it was scheduled to."There was a delay getting clearance to take off at Avalon airport due to a Jetstar flight, which was a slight issue, but one that would not cause delays during an actual fire," he said."The operation went to plan, the systems worked well, now it's just up to the researchers to see how effective it was."