The calculation pipeline.
Six deterministic steps turn a flight into an audit-ready footprint.
Flight & route
Each flight resolves to a route — either a great-circle path or a real ADS-B track (OpenSky/FR24 when available). The path is segmented across Flight Information Regions so emissions can be attributed to the right airspace and regulator.
Fuel burn
Burn is derived per aircraft + engine type across the full flight cycle — taxi/LTO and cruise — from published fuel-burn tables, then scaled by distance, payload and load factor.
Emission factors
Fuel mass is converted to CO₂ (and CO₂e) using IATA RP1726 and UK DEFRA 2025 factors. Every flight can be computed under more than one method so results are comparable and auditable.
SAF adjustment
Sustainable aviation fuel reduces the fossil share by its blend percentage and the certified carbon intensity of its pathway (e.g. HEFA), traced to ISCC proof-of-sustainability where claimed.
Non-CO₂ forcing
Contrail and NOₓ effects are estimated as CO₂-equivalent radiative forcing, with confidence intervals — the warming that fuel-only accounting misses.
Scope split & attribution
Results are split into Scope 1, 2 and 3 and mapped to the applicable schemes (CORSIA, EU ETS, ReFuelEU) per the airspace and operator, ready for reporting.
The three scopes, in detail.
Scope 1 — Direct emissions
- Jet-fuel combustion across taxi, take-off, climb, cruise and descent
- Fuel burn from aircraft + engine fuel-burn tables (LTO + cruise)
- SAF-blend reductions applied by pathway carbon intensity
- Non-CO₂ effects — contrails and NOₓ — as radiative forcing CO₂e
Scope 2 — Purchased energy
- Electricity and ground energy at hubs, stations and offices
- Net of renewable energy certificates (RECs) you retire
- Location- and market-based accounting so reported = procured
Scope 3 — Value chain
- Well-to-tank (WTT) fuel production and distribution
- Ground operations — APU, GPU and ground support equipment
- Upstream supply and purchased goods & services
Standards & methods we build on.
IATA RP1726
The airline-industry recommended practice for passenger and cargo CO₂ calculation — the baseline method for per-flight footprints.
UK DEFRA 2025
Government-published greenhouse-gas conversion factors, including well-to-tank, used as an alternative and cross-check method.
ICAO CORSIA
The international offsetting scheme for aviation — eligible-fuel rules, baselines and offsetting obligations tracked per operator.
Non-CO₂ radiative forcing
Contrail and NOₓ warming estimated as CO₂e with uncertainty ranges, following the current scientific consensus.
SAF pathways & ISCC
Carbon intensity by production pathway, with proof-of-sustainability certificates traced from supplier to flight.
Airspace-aware attribution
Emissions allocated across Flight Information Regions so each jurisdiction's share is defensible under audit.
Multiple methods, side by side
Compute it three ways. Reconcile the difference.
Every flight is calculated under IATA, DEFRA and CORSIA logic so you can see where methods diverge and why. The carbon ledger shows the working for each cell, exports for audit, and keeps an immutable record of every override.