Source: https://guthlabs.ai/docs/instruments/breguet-range-equation-calculator/implementation/

instrument implementation / implementation-contract

# Breguet Range Equation Calculator implementation

A source-bound implementation contract for Breguet Range Equation Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t5-055

**Effect**: Computation or source lookup only

## Input and validation requirements

The raw formulas produce an undefined result when c=0, so validation must reject that input. Additionally, an unspecified speed unit can change the computed range from 1673.5766349 to 860.9614583 for the same numerical speed value.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "aircraft_type": "jet",
    "cruise_speed": 250,
    "cruise_speed_unit": "m/s",
    "specific_fuel_consumption": 0.00025,
    "specific_fuel_consumption_unit": "1/s",
    "lift_to_drag_ratio": 17,
    "initial_weight": 240000,
    "final_weight": 180000,
    "weight_unit": "N"
  },
  "expected_outputs": {
    "range": 4890595.23,
    "range_unit": "m"
  },
  "working": "W1/W2 = 240000/180000 = 4/3. ln(W1/W2) = ln(4/3) = 0.28768207245. V/c = 250/0.00025 = 1,000,000 m. L/D × V/c = 17 × 1,000,000 = 17,000,000 m. R = 17,000,000 × 0.28768207245 = 4,890,595.23 m."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/breguet-range-equation-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/breguet-range-equation-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/breguet-range-equation-calculator/qualification/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json`

- `evidence-tranche5/tranche5-results.json`