USDA FOREST SERVICE, CALIFORNIA DEPT OF FORESTRY AND FIRE PROTEC· ICAO24 a559ca· last seen 2d ago

N444DF is a Marsh Aviation S-2T Turbo Tracker, a twin-engine turboprop operated by USDA FOREST SERVICE, CALIFORNIA DEPT OF FORESTRY AND FIRE PROTEC. SkyMeter has tracked 604 flights totalling 484 hours of airtime via ADS-B across 2 callsigns. The most frequent segment is KPRB to KPRB. Service window in our records spans 441 days. Of those flights, 50 (8.3%) 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
604
all time
FLOWN HOURS
484
tracked time
📍
AIRPORTS VISITED
42
unique
📡
CALLSIGNS
2
78 routes
📅
SERVICE PERIOD
5/29/2025 → 8/13/2026
first → last
INCIDENT RATE
8.3%
50 flagged

Top routes

By flight count

10
116
7
5
5
4
4
3

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 N444DF

50
8/13/2026
40m
No alerts
8/12/2026
41m
No alerts
8/12/2026
1h 33m
No alerts
8/12/2026
23m
No alerts
8/11/2026
1h 38m
No alerts
8/11/2026
1h 14m
No alerts
8/11/2026
42m
No alerts
8/11/2026
1h 30m
No alerts
8/11/2026
49m
No alerts
8/11/2026
44m
No alerts
8/11/2026
7m
No alerts
8/10/2026
35m
No alerts
8/10/2026
42m
No alerts
8/10/2026
2h 26m
No alerts
8/9/2026
1h 55m
No alerts
8/9/2026
36m
No alerts
8/9/2026
1h 37m
No alerts
8/9/2026
2h 15m
No alerts
8/9/2026
1h 16m
No alerts
8/8/2026
18m
No alerts
8/8/2026
17m
No alerts
8/8/2026
50m
No alerts
8/8/2026
47m
No alerts
8/7/2026
1h 22m
No alerts
8/6/2026
1h 36m
△ Low approach-stability score
8/6/2026
36m
No alerts
8/6/2026
2h 2m
No alerts
8/5/2026
53m
No alerts
8/5/2026
41m
No alerts
8/5/2026
2h 8m
No alerts
8/4/2026
1h 37m
No alerts
8/3/2026
30m
No alerts
8/3/2026
36m
No alerts
8/2/2026
59m
No alerts
7/31/2026
1h 6m
No alerts
7/29/2026
1h 3m
No alerts
7/29/2026
11m
△ Low approach-stability score
7/29/2026
19m
△ Low approach-stability score
7/29/2026
1h 13m
No alerts
7/24/2026
14m
No alerts
7/23/2026
53m
No alerts
7/23/2026
20m
No alerts
7/22/2026
15m
No alerts
7/22/2026
35m
No alerts
7/21/2026
4h 18m
No alerts
7/21/2026
21m
No alerts
7/21/2026
56m
No alerts
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