The LUU-1 flare burns for 30 minutes on the ground providing a colored flame. The LUU-1 flare enhances a pilot's ability to see targets while using Night Vision Goggles. With the introduction of A-10 Warthog Night Vision capability, such flares are not used as frequently as in the past as they provide too much light for the very sensitive goggles.
Flares burn at uneven rates and therefore fluctuate in brightness.