Federal Firefighting Contract Aviation Hours: 81% of LAT/VLAT Time Ran Exclusive-Use in 2021 — CWN Rates Still 54% Higher per Day

When a western megafire pushes past initial attack, incident commanders order large airtankers and Type 1 helicopters through two different procurement channels. Exclusive-use (EU) contracts — the Forest Service also labels them EXU in billing systems — pay vendors a daily availability retainer across a mandatory availability period so aircraft sit crewed and ready at tanker bases. Call-when-needed (CWN) contracts keep vendors on a basic ordering agreement: no guaranteed days, no guaranteed hours, but the agency can activate aircraft when fire activity outruns the EU fleet. The policy fight is familiar: EU buys readiness; CWN buys flexibility. The accounting question is sharper: what share of heavy aviation hours actually flies on each contract type, and how did unit costs move when CWN surged?

This dashboard joins USDA Forest Service calendar-year aviation utilization reports (CY2017–CY2021) with published EU vs CWN tariff benchmarks. The headline for CY2021: 6,247 of 7,678 LAT/VLAT flight hours (81.4%) billed on exclusive-use contracts, while CWN accounted for the remaining 1,431 hours (18.6%). That rebound followed CY2020, when a pandemic-era surge pulled CWN up to 3,950 hours — 46.1% of the LAT/VLAT total. On rates, a 2018 desk composite of next-generation large airtankers still shows CWN daily availability 54% above EU and hourly flight rates 18% above EU, even though CY2021's blended IBS flight-time cost fell to about $8,715 per hour from $9,525 in the surge year.

What the Forest Service counts as a flight hour

The utilization reports summarize Incident Business System (IBS) billing extracted through FAMWEB. Flight hours are calendar-year totals (January–December), not fiscal-year suppression appropriations and not acres burned. The airtanker category includes all fixed-wing retardant delivery by large airtankers (LAT) and very large airtankers (VLAT); single-engine airtankers and scoopers are tracked elsewhere. Type 1 helicopters are the heaviest rotor-wing tier on the national contract list — the category most comparable to LAT/VLAT for extended attack on large fires.

Important caveat: the reports do not filter to "large-fire" incident codes. LAT/VLAT assets are ordered overwhelmingly when fires escape initial attack, but the hour tables are contract-channel totals, not a NIFC fire-size cut. Treat the series as federal heavy-air suppression capacity utilization, not a precise large-fire-only denominator.

LAT/VLAT hours swing with fire years — and with surge policy

The five-year LAT/VLAT panel shows how contract-channel shares move when total demand shifts.

CY2019 was the quietest year in the panel at 3,427 total hours, with CWN LATs logging just 608 hours. CY2020 flipped the mix: total hours jumped to 8,575, and CWN LAT hours alone hit 3,707 — six times the 2019 CWN LAT tally and triple the five-year CWN LAT average published in the CY2021 report. The Forest Service explicitly tied that pattern to COVID-19 surge aircraft, extended CWN activations, and the first heavy use of surge capacity alongside EU assets.

CY2021 partially normalized the contract split even though total hours (7,678) stayed well above the quiet-year trough. EXU LAT hours rose to 5,355, while CWN LAT fell to 757 — below the five-year CWN LAT average. CWN VLAT hours, however, remained elevated at 673, delivering 5.3 million gallons of retardant, suggesting surge VLAT capacity stayed economically attractive even as LAT CWN activations cooled.

Type 1 helicopters tell a different contract story

Rotor-wing hours dominate agency aviation totals — helicopters were 53% of all Forest Service flight hours in CY2021 — but the contract channel for Type 1 heavy helos diverged from airtankers in those two years.

In CY2020, 19,293 of 19,434 Type 1 helicopter hours (99.3%) billed as CWN. The aviation report notes 28 Type 1 helicopters operated under modified CWN contracts while traditional exclusive-use Type 1 acquisitions were delayed, plus 42 additional surge helicopters contracted during the pandemic response. EU Type 1 hours that year totaled just 141.

CY2021 went further: zero Type 1 EU hours against 23,228 CWN hours because the agency awarded 48 Type 1 CWN/surge task orders after cancelling the planned Type 1 exclusive-use acquisition. Type 2 and Type 3 helicopters still flew meaningful EU hours (5,359 and 9,654 respectively in CY2021), but the largest rotor-wing tier — the one most often paired with LAT/VLAT on extended attacks — was entirely CWN-billed in the published tables.

That asymmetry matters for budget desks: a headline "81% EXU share" for airtankers coexists with a rotor-wing tier that was 100% CWN on Type 1 during the same window.

Unit costs: availability retainers vs flight-time tariffs

Forest Service airtanker contracts bill on two rails: daily availability (aircraft crewed and ready) and hourly flight time (retardant missions and repositioning). CY2021 LAT/VLAT expenditures totaled $180.3 million in IBS: $111.8 million (62%) availability, $66.9 million (37%) flight time, and roughly $1.9 million standby/other. CY2020 was more expensive at $206.6 million total despite similar hour volume, with flight-time pay at $81.7 million — implying about $9,525 per flight hour blended across EU and CWN versus $8,715 in CY2021.

Those blended figures are desk ratios, not published contract tariffs. They mix EU aircraft (flying more hours on retainer already paid) with CWN activations (higher daily and hourly schedules when ordered). They also include VLAT and LAT models with different fuel burns and retardant capacities.

Published 2018 contract benchmarks for next-generation large airtankers (BAe-146, RJ85, C-130 composite) remain the cleanest EU vs CWN spread:

The Forest Service's Large Airtanker Modernization Strategy (2018) summarized the trade even more bluntly: EU LAT all-in costs run about half of CWN assets because the retainer buys guaranteed capacity before the first drop. CWN can sit unused — or sit overseas when US demand spikes. Wildfire Today reported that in July 2021 the agency sought 16 CWN airtankers but could activate only five; others were committed abroad.

Why the mix shifted in 2020 and rebounded in 2021

Three mechanisms show up repeatedly in agency reports and aviation press.

Surge task orders. CY2020 introduced surge aircraft across airtankers, scoopers, helicopters, and aerial supervision at negotiated CWN rates. CY2021 continued 90-day CWN surge contracts (three LATs, two VLATs) alongside EU MAP aircraft.

Contract acquisition gaps. Type 1 helicopter EU acquisitions were cancelled or delayed, forcing CWN bridges. Airtanker EU counts fell to 18 EXU and five CWN on the CY2021 fleet summary — tighter than the CY2020 table listing 13 EXU and 22 CWN large airtanker line items — but EXU hours still dominated because MAP aircraft fly continuously while many CWN line items never receive orders in mild years.

Fire demand and cooperator billing. Roughly half of CY2021 LAT/VLAT hours supported non-Forest Service fires — 32% state/local and 18% Department of the Interior — under cost-recovery policies. Heavy EU utilization therefore reflects national pool demand, not only FS-managed incidents.

Reading the scatter: more CWN hours ≠ cheaper flight time

The dashboard's hours-versus-$/hour scatter plots CY2020 and CY2021 only (earlier years lack full pay-code disclosure in the desk extract). CY2020 combined higher total hours with higher implied flight $/hour despite the CWN-heavy mix. CY2021 reduced total LAT/VLAT cost 13% year over year while shifting hours back toward EU. That pattern fits the contract economics: CWN daily rates punish short activations, while EU spreads availability over more flight hours when fire seasons run long.

Caveats for analysts and appropriators

Calendar year vs fire season. Billing follows calendar-year IBS closes; late-season fires can push hours across year boundaries.

Dual awards and substitutions. Some aircraft hold both EU and CWN contracts; vendors substitute tails for maintenance. Fleet counts in summary tables do not equal utilized aircraft counts.

MAFFS and foreign cooperators excluded. Military Modular Airborne Fire Fighting System hours (945 fire-support hours in CY2021) and foreign agreement aircraft (e.g., New South Wales) are not in LAT/VLAT hour totals but still matter for large-fire capacity.

MATOC transition. Since 2023 the Forest Service has moved VLAT/LAT procurement toward Multiple Award Task Order Contracts (MATOC), blending legacy EU/CWN labels. Extend the panel only with new annual reports — do not extrapolate 2021 shares into 2024 fleet counts without fresh IBS extracts.

Helicopter generalization. Type 1 CWN dominance in CY2020–2021 may normalize when EU Type 1 contracts return; do not assume rotor-wing shares mirror airtanker shares.

What to watch next

Appropriations staff typically monitor EU MAP sizes, CWN activation success rates, and UTF (unable to fill) tanker requests — the Wildfire Today series tracks UTF percentages back to 2000. On costs, watch whether availability share of LAT/VLAT bills stays above 60% as EU fleets rebuild: that ratio signals how much of suppression aviation spend buys readiness versus retardant delivery. On operations, the interagency Aerial Firefighting Use and Effectiveness (AFUE) study lineage remains the authoritative path toward mission-level effectiveness metrics — but for contract structure, IBS hour splits by pay code remain the ground truth this dashboard charts.

The bottom line for CY2021: exclusive-use contracts still carried four-fifths of large airtanker flight hours, yet call-when-needed tariffs remained structurally more expensive, and the heaviest helicopter tier billed entirely through CWN. Federal wildfire aviation is not one contract story — it is a stack of readiness bets, surge valves, and rate schedules that only line up when you separate fixed-wing retardant hours from rotor-wing tiers and read availability separately from flight time.