Ryan Air Attack Ryan Air Attack is a joint Air Attack / Helitack base operated by the California Department of Forestry and Fire Protection (Riverside Unit). It is one of 19 tanker bases strategically located throughout California. The base provides initial attack aircraft service to over of private, state, and federally owned lands. Up until 1998, Ryan was statistically the busiest air tanker base in the United States, delivering an average of 1.5 million gallons of retardant annually. Currently two S-2 Trackers, an OV-10 and a UH-1H are stationed at the base. The base has served as the primary air attack base for many wildfires, including the Old Fire and Cedar Fire in 2003 and the Esperanza Fire in 2006. History of Ryan Air Attack The United States Forest Service commenced air tanker loading operations in 1957, and in 1959 California Division of Forestry (now Cal Fire) began their operation at Ryan field. Both agencies maintained separate parking, loading and mixing areas but the initial stages of a joint base operation had begun. In 1969, the United States Forest Service (USFS) and the California Division of Forestry (CDF) truly merged into a joint agency air attack base sharing the base operation, responsibilities and facilities. The joint base concept successfully continued operation until 1998 when the USFS moved their air tanker base operations to the larger and recently vacated Norton Air Force Base. From the beginning of Ryan Air Attack Base, Cal Fire and the USFS used privately owned contracted World War II vintage aircraft. The type and sizes of aircraft varied based on vendor, availability of flyable airframes and spare parts. As the years counted off and the flight hours increased these airplanes became static museum displays or were robbed for parts to keep the dwindling fleet flying. Because of the dwindling air tanker fleet, Cal Fire acquired excess U.S. Navy Grumman S-2A submarine hunting aircraft. These planes were converted from military use to firefighting aircraft using a design developed by Hemet Valley Flying Service. The first two aircraft build-ups were completed by Hemet Valley Flying Service and tested at Ryan Air Attack Base. The basic aircraft design has been in continuous state service since 1975. In 1977 Cal Fire began a two-week pilot helitack program using a contracted helicopter. Headed up by Captain Emil Derdowski and two firefighters, the program was eventually extended to a total of four weeks.