Breguet Range Equation Calculator mechanism

Model scope

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.

• 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.

Units and conventions

• 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.

Inspectable vector

One of 4 source-bound review vectors:

{
  "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."
}

Failure boundary

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.

Other records

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
• BOUNDARY_HAZARD_CATALOG.json