The role of large airtankers (LATs) in fire suppression in the United States has been the source of debate and discussion in recent years as the U.S. Forest Service has faced decisions to address an aging fleet of aircraft. Associated questions of fleet efficiency are complicated by limited historical data on operational use. A need for improved data collection systems for LATs was a key recommendation from a 2013 Government Accountability Office investigation into fleet modernization actions. Our research also identified deficiencies in data collection regarding LAT use in federal fire suppression.
Using drop location data from 2010-2012 for the conterminous U.S., we linked retardant drops to fire occurrence and resource ordering records to identify whether LATs were used during initial attack, and if so, whether or not the fire was contained at the initial attack phase. Our analysis showed that despite federal guidance stating that the priority use of LATs is for initial attack, 45% of drops occurred during extended attack. Further, containment rates of fires associated with LAT use were low; 75% of all initial attack drops were on fires that escaped initial attack containment efforts.
We also explicitly characterized the conditions of use for all LAT drops in order to qualify where and when drops occurred. Variables of particular interest were terrain, fuels, time of day, weather, and proximity to identified values at risk. Results showed that approximately 35% of drops occurred in late afternoon (1500 – 1800 hours) and nearly 40% of all drops intersected with timber fuel models. We explored possible causes for these results, addressed potential limitations with our methods and data, and offered recommendations for improvements in data collection related to aviation management.