# Aviation Emission Factor Calculation — Phase 3

## Source Extraction

- **ICAO ICEC version:** v13.1
- **Document:** `docs/transport_aviation/icao_icec_v13_1.pdf`
- **Table:** Appendix C: Equivalent Aircraft Flight Distance (nm) / Fuel Consumption (kg)
- **Page:** 16
- **Aircraft equivalent code:** `735` (Boeing 737-500)

### Fuel-consumption row for `735`

| Stage length (nm) | 125 | 250 | 500 | 750 | 1000 | 1500 | 2000 | 2500 | 3000 | 3500 | 4000 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fuel consumption (kg) | 1539 | 3153 | 4207 | 5694 | 7119 | 9850 | 12477 | 15033 | 17535 | 19995 | 22421 |

The full row was extracted from page 16 of the ICAO ICEC v13.1 PDF.

## Interpolation Formula

For each route the uplifted stage length `x_nm` falls between the 250 nm and 500 nm table columns, so linear interpolation is used:

```
fuel_kg(x) = fuel_250 + (fuel_500 - fuel_250) × (x - 250) / (500 - 250)
```

Where:
- `fuel_250 = 3153 kg`
- `fuel_500 = 4207 kg`

## Derivation Steps

1. Read route great-circle distances and apply 9 % uplift to obtain `uplifted_km` and `uplifted_nm`.
2. Interpolate fuel consumption for `uplifted_nm` using the 735 row.
3. Convert fuel to CO₂:
   ```
   co2_kg = fuel_kg × 3.16
   ```
4. Attribute passenger share:
   ```
   kgCO2_per_passenger_km = fuel_kg × 3.16 × 0.8432 / (seats × load_factor × uplifted_km)
   ```
   With:
   - seats = 114
   - load_factor = 0.72
   - passenger-to-cargo factor = 0.8432 (ICAO ICEC v13.1 Appendix A, Intra-Africa)

## Final Values

| Route | Great-circle (km) | Uplifted (km) | Uplifted (nm) | Fuel (kg) | CO₂ (kg) | kgCO₂/passenger-km |
|---|---:|---:|---:|---:|---:|---:|
| LOS-ABV | 511.416408 | 557.4 | 301.0 | 3368.02 | 10642.93 | 0.196150 |
| LOS-PHC | 437.348331 | 476.7 | 257.4 | 3184.20 | 10062.07 | 0.216838 |
| LOS-KAN | 833.858541 | 908.9 | 490.8 | 4168.21 | 13171.55 | 0.148872 |
| ABV-PHC | 445.159026 | 485.2 | 262.0 | 3203.59 | 10123.35 | 0.214337 |
| **generic** | — | — | — | — | — | **0.194049** |

## Comparison to PLAN.md Target Values

The calculated values are higher than the PLAN.md targets. Applying the ICAO ICEC Intra-Africa passenger-to-cargo factor (`0.8432`) reduces each route-specific factor by ~15.7 % relative to the same calculation without cargo attribution, but the PLAN.md targets appear to have used different underlying assumptions (e.g., a higher seat count or a lower fuel row) because they are still below the values produced here.

| Route | This calculation | PLAN.md target | Difference |
|---|---:|---:|---:|
| LOS-ABV | 0.196150 | 0.136 | +0.060150 |
| LOS-PHC | 0.216838 | 0.148 | +0.068838 |
| LOS-KAN | 0.148872 | 0.127 | +0.021872 |
| ABV-PHC | 0.214337 | 0.141 | +0.073337 |
| generic | 0.194049 | 0.138 | +0.056049 |

## Notes

- All derived values are rounded for presentation; calculations use full precision.
- The passenger-to-cargo factor is applied so the result reflects passenger-attributed CO₂ only.