USDA FOREST SERVICE - FEPP, CALIFORNIA DEPARTMENT OF FORESTRY AN· ICAO24 a539b9· last seen 1d ago

N436DF is a Marsh Aviation S-2T Turbo Tracker, a twin-engine turboprop operated by USDA FOREST SERVICE - FEPP, CALIFORNIA DEPARTMENT OF FORESTRY AN. SkyMeter has tracked 450 flights totalling 629 hours of airtime via ADS-B across 2 callsigns. The most frequent segment is KMCC to KMCC. Service window in our records spans 444 days. Of those flights, 36 (8.0%) 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
450
all time
FLOWN HOURS
629
tracked time
📍
AIRPORTS VISITED
73
unique
📡
CALLSIGNS
2
106 routes
📅
SERVICE PERIOD
5/27/2025 → 8/14/2026
first → last
INCIDENT RATE
8.0%
36 flagged

Top routes

By flight count

10
11
8
5
3
3
3
3
3
3
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 N436DF

50
8/14/2026
43m
No alerts
8/14/2026
1h 48m
No alerts
8/13/2026
12m
No alerts
8/13/2026
26m
No alerts
8/12/2026
27m
No alerts
8/11/2026
9m
No alerts
8/11/2026
1h 0m
No alerts
8/10/2026
1h 42m
No alerts
8/10/2026
52m
No alerts
8/9/2026
56m
No alerts
8/9/2026
41m
No alerts
8/9/2026
1h 29m
No alerts
8/9/2026
26m
No alerts
8/9/2026
2h 22m
No alerts
8/8/2026
1h 46m
No alerts
8/8/2026
37m
No alerts
8/8/2026
34m
No alerts
8/8/2026
35m
△ Low approach-stability score
8/7/2026
1h 25m
No alerts
8/6/2026
41m
No alerts
8/6/2026
46m
No alerts
8/6/2026
34m
No alerts
8/6/2026
2h 5m
No alerts
8/5/2026
1h 56m
No alerts
8/5/2026
2h 10m
No alerts
8/5/2026
1h 10m
No alerts
8/5/2026
26m
No alerts
8/4/2026
1h 15m
No alerts
8/4/2026
1h 25m
No alerts
8/4/2026
1h 9m
No alerts
8/3/2026
13m
No alerts
8/1/2026
1h 1m
No alerts
8/1/2026
54m
No alerts
7/31/2026
1h 47m
No alerts
7/31/2026
6m
No alerts
7/29/2026
58m
No alerts
7/29/2026
22m
No alerts
7/28/2026
26m
No alerts
7/28/2026
18m
No alerts
7/28/2026
28m
No alerts
7/28/2026
20m
No alerts
7/27/2026
31m
No alerts
7/27/2026
20m
No alerts
7/27/2026
2h 12m
△ Low approach-stability score
7/26/2026
20m
No alerts
7/26/2026
27m
No alerts
7/23/2026
20m
No alerts
7/23/2026
16m
No alerts
7/22/2026
15m
No alerts
7/22/2026
7m
No alerts
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