Dropping fire suppressant and retardant from aircraft provides great support to firefighters on the ground at bushfires—during daylight. So why isn’t standard practice to continue firebombing operations into the night?
Fighting bushfires at night takes advantage of cooler conditions, higher humidity and more moderate fire behaviour. Importantly, controlling a fire overnight may be critical in preventing a major flare-up the following day. So why not?
The good news is …. it does currently happen in some parts of the world and Australian agencies are currently working hard to test and introduce a limited night firebombing capability. The main issue is that firebombing is an inherently visual operation. Pilots need to clearly see and avoid terrain, obstructions, smoke and cloud and they need to eyeball their targets. For some decades, helicopters and fixed-wing aircraft have routinely operated using Night Vision Imaging Systems (NVIS) such as Night Vision Goggles (NVG) to intensify available light at night time to allow safe visual flight. NVIS have their limitations, such as lack of depth perception and a narrow field of view, however, the technology has improved steadily and it is now viable to undertake night firebombing in Australia, at least under some conditions. NVIS are already widely used in Australia in police and air ambulance work, and increasingly in bushfire support for activities that occur at greater heights aboveground than firebombing, such as gathering intelligence and dropping incendiaries. The National Aerial Firefighting Centre has a number of NVIS-equipped helicopters and fire agencies across the country are routinely using NVIS helicopters for bushfire support. A small number of fire and rescue agencies in north America have had NVIS firebombing programs for some time. Overall, this body of experience provides valuable insight for developing a safe and effective night firebombing capability in Australia
There are risks. Firebombing is conducted close to the ground. At night, the chances of flying into low visibility and colliding with obstructions like power lines and trees are increased. Hovering a helicopter (to land or to hover- fill) requires clear visual references that may be obscured more easily at night. Options to deal with aircraft emergencies become more limited. The NVIS systems may be affected by excess light generated by the fire. These risks need to be carefully managed and controlled. There are also significant regulatory considerations. Australian civil aviation legislation is quite progressive  in allowing civilian NVIS operations with helicopters but, understandably, high standards are required and there are plenty of hoops to jump through.