Careful dance keeps flames in check
In the smoke-filled skies, helicopters and airplanes are performing a choreographed dance while attacking the Pigeon Valley fire from above.
Aircraft have descended on Nelson from all over the country, fighting the blaze with monsoon buckets since Tuesday afternoon. The pilots remain in constant radio contact with each other, each knowing the next move of every chopper.
‘‘Everybody looks out for everybody,’’ Nelson Marlborough Rescue Helicopter pilot Barry McAuliffe said.
‘‘Most of the guys know each other within the industry. You know who you’re following, and you stay in that sequence the whole time.’’
The helicopters dump more than 500 litres of water from each bucket. Most carry 800 to 1000 litres per sortie.
Watching them release the water over the raging fires, some might wonder how the sprinkle could affect a towering inferno. Aerial firefighting foam is pumped into the buckets, making the water more effective and stopping it evaporating from the heat of the fire.
How the water attack was approached depended on the site, McAuliffe said.
‘‘If it’s an open grassy area, you do a running drop – keeping moving as we release the water to make the drop spread more and disperse it to a finer mist, which is quite effective.’’
Water is taken from forestry or farming dams, with ‘‘the better ones’’ being refilled by ground firefighting crews.
The helicopters are given direction on which areas to target from a smaller machine with a Fire and Emergency New Zealand (FENZ) air attack supervisor observing from above.
The pilots warn each other of wires to look out for, the best water spots, and flying conditions around certain areas.
FENZ incident controller John Sutton said special trucks with deep containers were brought in on Friday for the helicopters to dip their buckets into.
He said there were no concerns about running out of water. ‘‘We’d use salt water if it was close enough.’’
Each helicopter’s fuel lasts about an hour, and the pilots are rostered in and out to manage fatigue.
Unlike the ground crews that work through the night, the pilots have limited visibility at night through the smoke, and most of the choppers aren’t compatible with night-vision goggles.
‘‘We’re all experienced pilots, and we know what our limits are,’’ McAuliffe said.
‘‘There are times where it’s not safe to be in an area, so we shift – (it) could be due to visibility, wind conditions, could be due to any number of hazards, but it’s all just managed.’’