Source: https://guthlabs.ai/docs/instruments/breguet-range-equation-calculator/
instrument / verified-clean
# Breguet Range Equation Calculator
The current ledger marks this instrument verified clean within the source-bound verification corpus.
Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**
## Inspectable records
[01**Overview**Purpose and lifecycle]()[02**Mechanism**Method and assumptions]()[03**Implementation**Binding and validation]()[04**Qualification**Evidence and errata]()
## Ledger state
The current ledger marks this instrument verified clean within the source-bound verification corpus.
**Area**: Thermodynamics, Fluids & Aero
**Tranche**: tranche-5
**Evidence ID**: t5-055
**Ledger rows**: 1
No ledger note is attached.
## Review findings
The algebra is correct under the stated unit assumptions. The specification needs an explicit definition and unit requirement for c for each aircraft type, explicit validation constraints for W1, W2, c, eta, and L/D, and a declared output-unit policy. The honest label is appropriate but should also state that the estimate assumes constant cruise parameters and excludes climb, descent, maneuvering, reserves, and other operational fuel.
### Formula and scope findings
- The jet formula is standard only when c is thrust-specific fuel consumption (TSFC) with units of inverse time, such as 1/s or 1/h.
- The propeller formula is standard only when c is power-specific fuel consumption expressed as fuel weight flow divided by power, which has units of inverse length; using mass-specific consumption requires an explicit gravitational conversion.
- The input description says only “specific fuel consumption” and does not distinguish jet TSFC from propeller power-specific fuel consumption.
- The output range unit is not specified; it is determined by the consistent units used for V and c in the jet formula or c alone in the propeller formula.
### Unit assumptions
- W1 and W2 must use the same units; because they occur as a ratio, either both weights or both masses are acceptable.
- For jets, V and c must use compatible time units: for example, m/s with c in 1/s, or km/h with c in 1/h.
- For propeller aircraft, c must be in inverse length, such as 1/m, when the formula is used directly; eta is dimensionless.
- The natural logarithm ln is used.
- The formulas assume steady, level cruise with constant speed, efficiency, specific fuel consumption, and L/D.
## Boundary hardening
**BREAK_CLAIMED** · SELF_FLAGGED
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.
## Errata and corrections
No applied erratum is attached to this unique-name record.
## Inspectable example
4 review vectors are recorded. One source-bound sample is shown below.
````
{
"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."
}
````
## Related workflows
No source-defined multi-instrument workflow membership is recorded.
## Sources and evidence
These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.
- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`
- `evidence-tranche5/tranche5-results.json`
- `BOUNDARY_HAZARD_CATALOG.json`