USDA FOREST SERVICE FEPP, CALIFORNIA DEPT OF FORESTRY AND FIRE P· ICAO24 a53d70· last seen 1d ago

N437DF is a Marsh Aviation S-2T Turbo Tracker, a twin-engine turboprop operated by USDA FOREST SERVICE FEPP, CALIFORNIA DEPT OF FORESTRY AND FIRE P. SkyMeter has tracked 516 flights totalling 405 hours of airtime via ADS-B across 2 callsigns. The most frequent segment is KHMT to KHMT. Service window in our records spans 373 days. Of those flights, 16 (3.1%) carry at least one detected incident: a go-around, unstable approach, stall warning, or runway excursion. The Marsh Aviation S-2T Turbo Tracker has a maximum takeoff weight of 28,500 lb, medium wake category.

About the Marsh Aviation S-2T Turbo Tracker

The S-2T Turbo Tracker is a turboprop conversion of the Cold War-era Grumman S-2 Tracker anti-submarine aircraft, transformed into one of the most capable single-engine-out airtankers in the aerial firefighting fleet. Marsh Aviation of Mesa, Arizona developed the conversion in the 1980s, replacing the original piston radials with twin Garrett TPE331-14GR turboprops and adding a 1,200-gallon retardant tank system. The result is an aircraft that combines the rugged carrier-capable airframe of a 1950s naval design with modern turbine reliability and the ability to operate from short, high-altitude airstrips near active wildfires.

The S-2T's low-and-slow delivery profile (it can drop retardant at speeds around 130 knots just above treetop level) makes it particularly effective for initial attack on fast-moving fires in mountainous terrain. Its twin-engine configuration provides crucial safety margins when operating in the hot, high, and heavy conditions typical of Western U.S. fire seasons, and the type's excellent single-engine performance has made it a mainstay of state and federal firefighting agencies.

The California Department of Forestry and Fire Protection operates the largest fleet, with aircraft often seen working the steep canyons of the Sierra Nevada and coastal ranges. SkyMeter has tracked flights across airframes and operators, with the largest observed operator.

FLIGHTS
516
all time
FLOWN HOURS
405
tracked time
📍
AIRPORTS VISITED
48
unique
📡
CALLSIGNS
2
77 routes
📅
SERVICE PERIOD
07/09/2025 → 07/17/2026
first → last
INCIDENT RATE
3.1%
16 flagged

Top routes

By flight count

10
110
7
5
4
4
3
3
3
2
2

Flight numbers

Most-flown by this airframe

2

Aircraft specifications

Marsh Aviation S-2T Turbo Tracker

Engines
Twin Turboprop
Vref (approach)
95 kt
MTOW
28,500 lb
Wake category
M

Recent flights

Newest 50 operations of N437DF

50
07/17/2026
52m
No alerts
07/17/2026
1h 17m
No alerts
07/16/2026
53m
No alerts
07/16/2026
40m
No alerts
07/16/2026
1h 11m
No alerts
07/15/2026
40m
No alerts
07/15/2026
1h 8m
No alerts
07/14/2026
41m
No alerts
07/13/2026
30m
No alerts
07/13/2026
21m
No alerts
07/12/2026
37m
No alerts
07/11/2026
8m
No alerts
07/11/2026
5m
No alerts
07/11/2026
10m
No alerts
07/11/2026
2h 26m
No alerts
07/10/2026
42m
No alerts
07/10/2026
1h 55m
No alerts
07/09/2026
12m
No alerts
07/09/2026
12m
No alerts
07/09/2026
2h 1m
No alerts
07/08/2026
1h 27m
No alerts
07/07/2026
1h 33m
No alerts
07/07/2026
14m
No alerts
07/07/2026
37m
No alerts
07/07/2026
1h 27m
△ Low approach-stability score
07/06/2026
42m
No alerts
07/05/2026
1h 9m
No alerts
07/04/2026
1h 12m
No alerts
07/04/2026
7m
No alerts
07/03/2026
21m
No alerts
07/03/2026
1h 7m
No alerts
07/02/2026
43m
No alerts
07/02/2026
2h 15m
△ Low approach-stability score
07/01/2026
24m
No alerts
07/01/2026
28m
No alerts
06/30/2026
39m
No alerts
06/30/2026
52m
No alerts
06/30/2026
34m
No alerts
06/30/2026
45m
No alerts
06/29/2026
37m
No alerts
06/27/2026
2h 0m
No alerts
06/27/2026
15m
No alerts
06/26/2026
39m
No alerts
06/23/2026
31m
No alerts
06/22/2026
18m
No alerts
06/22/2026
1h 35m
No alerts
06/22/2026
26m
No alerts
06/22/2026
43m
No alerts
06/20/2026
17m
No alerts
06/18/2026
16m
No alerts
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