Air Tractor (AT-301 through AT-802F Fire Boss)

Air Tractor is the dominant purpose-built agricultural aircraft manufacturer in North America, building single-seat low-wing turboprop (and originally radial-piston) ag-planes in Olney, Texas. The company was founded in 1974 by Leland Snow, who had previously designed the Snow S-1 (1953) and S-2 series (built in Olney from 1958) before selling Snow Aeronautical to Rockwell-Standard in 1965. After leaving Rockwell, Snow designed a new, larger ag plane beginning in 1972; construction of the prototype AT-300 (redesignated AT-301) started in 1972 and first flew in 1973. Air Tractor delivered its 1,100th airplane in 1993, the 2,000th in 1998, and has since become the world's highest-volume ag-plane manufacturer, with the AT-502 and AT-802 as flagship models.

Unlike most of the GA fleet covered in this wiki, Air Tractors are not personal airplanes — they are FAR Part 137 working machines flown by commercial aerial applicators and Part 137/firefighting contractors. They are certified in the Restricted Category and are not eligible for normal passenger-carrying operations. The AT-802F Fire Boss variant, equipped with Wipaire amphibious floats, is the world's most prolific Single Engine Air Tanker (SEAT) and functions as a Type III air tanker capable of scooping water from lakes and delivering up to 14,000 gallons per hour on extended attack. See cargo-hauling for mission context; direct competitors are ayres-thrush (the former Snow/Rockwell/Ayres lineage), and the much smaller/older piper-pawnee and cessna-188-agwagon.

Air Tractor performance is reported at the working weight the airplane flies at, not the clean ferry condition. Loaded with a full hopper and spray boom, cruise drops 10–15 knots below book; the AT-802 books 167 KTAS clean but typically works swaths at 140–150 KIAS. With Fire Boss floats installed, the AT-802F loses roughly 25 knots of cruise speed and requires ~3,300 ft of water run to scoop a full 800-gallon load. Service ceiling (13,000 ft for the AT-802) is academic — ag work happens at 5–50 ft AGL, and fire drops are run at 60–150 ft. High-altitude fire bases (Western US, Chile, Turkey) are the real density-altitude headache; hot-and-high scooping margins can be thin enough that operators reduce load fractions. The PT6A is exceptionally reliable, but the ag environment (dust, chemical corrosion, hot-section salt exposure in fire work) drives hot-section inspections well short of book intervals. See maintenance-ecosystem.

The AT-802's 16,000 lb gross weight breaks down roughly as: 6,505 lb empty, 1,700 lb usable fuel (254 gal), leaving ~7,800 lb of hopper load — equivalent to 800 gallons of water (at 8.34 lb/gal) or ~960 gallons of spray mix depending on specific gravity. This is a working-load calculation: ferry range with full fuel and empty hopper is approximately 450 nm; loaded with a full hopper, operational radius is measured in miles not hundreds-of-nm because the aircraft returns to base between loads.

On a Fire Boss configuration, float installation costs ~1,100 lb of useful load, so scooped water load drops to ~6,500 lb (780 gal) at sea-level standard day. Hot/high scooping (e.g., 6,000 ft MSL lake, ISA+20) further reduces scoop load to ~600 gal due to takeoff-performance limitations coming off the water. Fuel is typically reduced to 150 gal (1,005 lb) in heavy-attack operations to preserve scoop payload, trading on-station endurance for drop quantity. This payload-fuel tradeoff is the central tactical equation of SEAT operations and is why the Fire Boss thrives on short tanker-base-to-fire cycles rather than long ferry missions.

Sources:

• Air Tractor - Wikipedia
• Air Tractor AT-802 - Wikipedia
• Air Tractor AT-500 family - Wikipedia
• Air Tractor AT-602 - Wikipedia
• Air Tractor AT-400 - Wikipedia
• AT-802F Official Specifications
• AT-802U Official Specifications
• Air Tractor Heritage
• Covington Aircraft - Air Tractor PT6A History
• Fire Boss LLC
• planephd - Air Tractor AT-502B
• planephd - Air Tractor AT-802
• Alexander Aviation - Agricultural Aviation Insurance
• AgAir Update - How Much Does It Cost?

• Flight training (1) — Not a trainer; only the AT-504 two-seat variant is used for type-specific ag pilot transition, and seat-time on 502s is earned, not scheduled.
• Backcountry (2) — Long flat strips yes, unimproved mountain strips no. The tail-dragger gear is rugged but the wingspan and turning radius rule out most bush strips.
• Business travel (1) — Single-seat, restricted category, no passenger ops.
• Aerobatics (1) — Not approved.
• Cross-country (2) — Ferry flights are routine (Olney to delivery worldwide) but the airplane is not a travel machine.
• Cargo hauling (9) — This is literally what it exists for. 800 gallons of dispersant or 820 gal of water is industry-leading single-engine payload. See cargo-hauling.
• Local fun (1) — No.
• Surveying (3) — Overkill; slower, cheaper platforms dominate. Some AT-802s carry sensor pods in military ISR roles (AT-802L Longsword, AT-802U Sky Warden).

Ag Air Tractors historically ran minimal panels — airspeed, altimeter, engine gauges, a handheld GPS, and a Satloc or Ag-Nav GNSS swath guidance system dominating the glareshield. Modern factory panels integrate Garmin G600 TXi or G3X Touch PFDs with GPSS coupling to the Satloc/Ag-Nav system. Fire Boss aircraft add Trotter Controls or Simplex FRDS gate controllers, fire-suppression radios (VHF-AM, VHF-FM for ground coordination), and TCAS/ADS-B In displays. IFR equipage is rare but not unheard of on Fire Boss aircraft that ferry between bases. No autopilot is installed in ag ops; Fire Boss aircraft use single-axis wing levelers on ferry legs.

• CP Products/Transland spray systems — Swath-width and droplet-spectrum upgrades; near-universal.
• Wipaire 10000 amphibious floats (Fire Boss conversion) — The defining AT-802F modification; ~$1.1M float set plus installation. Adds SEAT scooping capability.
• PT6A-65AG / -67AG re-engine STCs — Popular on older AT-502 airframes to add payload and climb margin.
• Trotter Controls FRDS Mk III gate — Computerized coverage-level dispersal on firefighting conversions.
• Covington and Dallas Airmotive hot-section/overhaul programs — Not STCs per se but the backbone of fleet support.
• Ag-Nav Guia / Satloc Bantam — GNSS flow-control swath systems integrated via STC.

Air Tractor Inc. (Olney, TX) runs one of the best-supported OEM parts operations in general aviation — parts availability is excellent, and the factory directly supports the global fleet with AOG response. Authorized service centers include Lane Aviation (Rosenberg TX), Valley Air Crafts, Farm Air, Frost Flying, and international dealers in Australia, Brazil, South Africa, and Europe. PT6A overhauls are handled by Covington Aircraft, Dallas Airmotive, Standard Aero, and P&W Canada. A&P familiarity is a specialist skill — a generalist GA mechanic cannot reasonably work on an AT-802 without type-specific training. Typical operating cost (excluding engine reserve) runs $350–$550 per hour; with PT6A reserve and insurance, direct operating cost is $750–$1,100/hr for an AT-802. See maintenance-ecosystem.

Expensive items: PT6A hot-section inspections ($45k–$85k), PT6A overhauls ($400k–$500k), spar-cap inspection/replacement ($50k–$250k), Wipaire float annual inspection and corrosion repair, spray system pumps and gearbox.

Air Tractor values are driven almost entirely by: (1) engine status (PT6A hot-section and overhaul position), (2) airframe fatigue life remaining against the spar AD, (3) spray system / fire gate configuration, and (4) avionics/GNSS system generation. See valuation-methodology.

Representative used-market pricing (2025–2026):

• AT-301 (piston R-1340): $100k–$175k, mostly parts/re-engine projects
• AT-402B (mid-time): $300k–$475k
• AT-502A/B (mid-time PT6A): $500k–$950k
• AT-602 (mid-time): $700k–$1.1M
• AT-802A ag config: $900k–$1.6M
• AT-802F Fire Boss (with Wipaire 10000 floats): $1.8M–$3.0M+

A fresh PT6A-67AG overhaul is approximately $425,000 and can add nearly the full overhaul cost to resale value on an otherwise-sound airframe. Conversely, an airframe nearing spar-cap replacement can discount $150,000–$300,000 off comparables.

• Wing spar ADs — Air Tractor has a long history of wing lower-spar-cap fatigue ADs, particularly AD 2014-25-03 and follow-on actions requiring repetitive eddy-current inspection of the lower wing spar cap on AT-300/400/500/600/800 series. Compliance drives significant shop downtime and mid-life spar-cap replacement on high-time airframes.
• Hopper attach fittings — Recurring SB and AD actions on hopper-to-fuselage attach hardware due to corrosive chemical exposure.
• Flap system cables and bellcranks — Routine replacement items on high-cycle spray aircraft.
• PT6A hot-section distress — Ag environment (dust/sand ingestion) and fire work (particulate from smoke) both reduce time between hot-section inspections below published schedules.
• Tailwheel lock and steering — High-cycle components; common write-ups at annual.
• Spray boom corrosion and electrolytic pitting — Not airworthiness but huge maintenance cost center.

Pre-buy red flags: undocumented spar AD compliance status, corrosion under hopper and in lower fuselage, non-overhauled PT6A approaching hot-section, mismatched flight hours vs. fatigue cycles (agricultural fatigue spectrum is severe).

Agricultural turbine hull & liability is a specialist line. See insurance-underwriting. Typical AT-802 hull value $1.2M–$1.8M; annual premiums run around $22,000–$32,000 for an experienced Part 137 operator with clean loss history, scaling higher for Fire Boss operations (wildland-fire pollution/drift exclusions, wire-strike exposure, water-scoop operations all add load). Operators with <1,000 hours ag time are typically uninsurable without a check-pilot mentoring program. Per-hour insurance cost is roughly $50–$70 at 500 annual hours. Pollution/drift liability is a mandatory add-on under FAR Part 137 that standard GA brokers routinely underwrite incorrectly.