N508JR

N508JR is a Marsh Aviation S-2F/S-2T Turbo Tracker, a twin-engine turboprop operated by GARRISON WILLIAM E JR. SkyMeter has tracked 30 flights totalling 16 hours of airtime via ADS-B. The most frequent segment is 1KS7 to US-2546. Service window in our records spans 232 days. The Marsh Aviation S-2F/S-2T Turbo Tracker has a maximum takeoff weight of 28,500 lb, medium wake category.

About the Marsh Aviation S-2F/S-2T Turbo Tracker

The S-2T Turbo Tracker represents one of aviation's most successful second lives: a Cold War submarine hunter reborn as a frontline firefighting airtanker. Originally designed by Grumman as the carrier-based S-2 Tracker for the U.S. Navy in the 1950s, these twin-engine aircraft patrolled the seas hunting Soviet submarines until retirement in the 1970s. Marsh Aviation of Arizona then pioneered a radical conversion in the 1980s, replacing the original piston engines with Garrett TPE331 turboprops and adding a 1,200-gallon retardant tank where sonobuoys and torpedoes once lived. The transformation created an airtanker purpose-built for the low-altitude, high-heat environment of wildfire suppression.

The S-2T's naval DNA makes it uniquely suited to firefighting. Its rugged airframe was engineered for carrier landings and low-level maritime patrol, giving it exceptional strength and maneuverability at the altitudes where airtankers work. The turboprop engines deliver reliable power in hot, high conditions where piston engines struggle, and the aircraft's relatively compact size allows it to operate from shorter airstrips near remote fire zones. With a cruise speed around 180 knots and the ability to make multiple drops per sortie, the S-2T became a workhorse for state and federal agencies across the American West. California Department of Forestry and Fire Protection (CAL FIRE) operates the largest fleet, with aircraft based at air attack bases throughout the state.

While newer purpose-built airtankers have entered service, the S-2T remains valued for its proven reliability and lower operating costs compared to jets. The type typically operates at weights up to 28,500 pounds, with approach speeds around 95 knots allowing precise drops in confined terrain. Most examples flying today are ex-Navy airframes from the 1950s and 1960s, now logging their sixth or seventh decade of service in a mission their designers never imagined. SkyMeter has tracked flights across airframes and operators, with the largest observed operator.