Flight: DEFRA 🇬🇧

💡 High-Level Description:

The Department for Environment, Food, and Rural Affairs (DEFRA) of the United Kingdom plays a key role in shaping environmental policies and approaches to carbon reduction. As part of its sustainability initiatives, DEFRA has developed a carbon calculation methodology specifically for the flight passenger sector, providing a standardized and credible means to evaluate the emissions associated with air travel.

DEFRA's methodology for evaluating carbon emissions from passenger flights incorporates a range of factors. These include the aircraft's fuel consumption, flight distance, type of aircraft, and even the indirect effects of high-altitude emissions. The aim is to offer a holistic view of a flight's environmental impact. By developing this standardized approach, DEFRA not only aids the aviation industry in understanding and reducing its carbon footprint but also provides a reliable reference point for policymakers and environmental advocacy groups.

Versioning: Add methodology_version to pin a specific Conversion Factors year (e.g., "2024"). If omitted, SQUAKE uses the latest supported year.

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Sample API Requests

A. Without audit mode (for pre-booking/quotes)

{
  "expand": ["items"],
  "items": [
    {
      "audit": false,
      "type": "flight",
      "methodology": "DEFRA",
      "external_reference": "test_4",
      "number_of_travelers": 2,
      "origin": "LON",
      "destination": "LAX",
      "booking_class": "first",
      "aircraft_type": "737",
      "radiative_forcing_index": true,
      "energy_scope": "wtw",
      "methodology_version": "2024"
    }
  ]
}

B. With audit mode (for finalized/post-booking calculations)

{
  "expand": ["items"],
  "audit_for": "<Auditable Entity ID>",
  "items": [
    {
      "audit": true,
      "type": "flight",
      "methodology": "DEFRA",
      "external_reference": "test_4",
      "number_of_travelers": 2,
      "origin": "LON",
      "destination": "LAX",
      "booking_class": "first",
      "aircraft_type": "737",
      "radiative_forcing_index": true,
      "energy_scope": "wtw",
      "methodology_version": "2024"
    }
  ]
}

Note: audit_for is optional. Provide when calculating on behalf of a specific Auditable entity; otherwise omit.

• Default Values

  • "booking_class": "average"

  • "energy_scope": "wtw"

  • "radiative_forcing_index": true

  • "methodology_version": latest supported DEFRA year (default if omitted)

• Calculation Specifics

  • An 8% uplift is applied to Great Circle Distance (GCD) to account for indirect paths, delays, etc.

  • If both distance_in_km and origin/destination are provided, distance_in_km takes precedence.

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API Request Items

• "type": "flight" (required)

• "methodology": "DEFRA" (required)

• "methodology_version": DEFRA Conversion Factors year (e.g., "2024"). Optional; if omitted → latest supported year.

• "external_reference": Unique identifier (max 128 chars).

• "number_of_travelers": Minimum 1 (default: 1).

• "origin": For airports use IATA/ICAO code (format: ^[A-Z]{3,4}$, e.g. "MUC"), for other locations used in trade and transportation use UN/LOCODE codes (format: ^[A-Z]{2}\W?[A-Z2-9]{3}$, e.g. "DEHAM"). You can also pass lat/long (format: ^[-+]?\d{1,3}\.\d{1,10}\s?,\s?[-+]?\d{1,3}\.\d{1,10}$, e.g. "+40.712,-74.006").

• "destination": For airports use IATA/ICAO code (format: ^[A-Z]{3,4}$, e.g. "MUC"), for other locations used in trade and transportation use UN/LOCODE codes (format: ^[A-Z]{2}\W?[A-Z2-9]{3}$, e.g. "DEHAM"). You can also pass lat/long (format: ^[-+]?\d{1,3}\.\d{1,10}\s?,\s?[-+]?\d{1,3}\.\d{1,10}$, e.g. "+40.712,-74.006").

• "distance_in_km": If present, overrides origin/destination resolution.

• "booking_class": If not provided, pass fare_class + airline to auto-resolve; default: "average".

• "aircraft_type": IATA/ICAO code; only applied when at least one airport is in the UK.

• "fare_class" / "airline": Mutually exclusive with "booking_class".

• "radiative_forcing_index": Apply high-altitude climate impact multiplier (default: true).

• "sustainable_fuels": Indicates SAF use (reduces emissions in SQUAKE; not part of official DEFRA factors).

• "carbon_reduction_percentage_of_total": Fraction 0–1 from SAF; default: 0.

• "energy_scope": "wtw" (default) or "ttw".

• "audit": boolean (optional). Set to true to create immutable audit records for finalized calculations. Must be enabled for your account.

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Aircraft Type Distribution

Domestic	Short-Haul	Long-Haul
32N	32N	32N
32Q	32Q	32Q
319	318	320
320	319	321
321	320	332
AT4	321	333
AT5	332	339
AT7	333	343
738	359	359
D38	AT7	338
ER3	7M8	7M8
ER4	7M9	738
E70	733	752
E90	734	763
E95	735	764
J41	736	772
SF3	737	773
	738	77F
	739	77W
	752	788
	753	789
	763	781
	772
	77W
	788
	789
	221
	223
	CR9
	DH8
	E70

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Sample API Response

{
  "carbon_quantity": 15273823,
  "carbon_unit": "gram",
  "items": [
    {
      "carbon_quantity": 15273823,
      "carbon_unit": "gram",
      "external_reference": "test_4",
      "type": "flight",
      "methodology": "DEFRA",
      "methodology_version": "2024",
      "distance": 8804.0,
      "distance_unit": "kilometer"
    }
  ]
}

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Versions

• Behavior: If methodology_version is omitted, SQUAKE automatically applies the latest supported DEFRA Conversion Factors year. Pin a year for reproducibility and audit readiness.

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Bibliography

• UK Government — Greenhouse gas emissions: Research & statistics: https://www.gov.uk/environment/greenhouse-gas-emissions#research_and_statistics

• Bramwell, R., et al. (2024). Government Greenhouse Gas Conversion Factors for Company Reporting — Methodology. (Methodology paper PDF).