Standard Atmosphere (ISA) Calculator implementation

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

t6-055

Effect

Computation or source lookup only

Input and validation requirements

An extreme finite altitude such as 1e308 m can drive the piecewise arithmetic into overflow and a negative-temperature, non-integer-power domain error unless the input is range-checked and rejected. The branch boundary also requires an explicit convention for whether exactly 11000 m belongs to the lower or upper layer.

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": {
    "geopotential_altitude_m": 0
  },
  "expected_outputs": {
    "T_K": 288.15,
    "P_Pa": 101325,
    "rho_kg_m3": 1.225,
    "a_m_s": 340.294,
    "sigma": 1
  },
  "working": "At sea level: T = 288.15 - 0.0065*(0) = 288.15 K. P = P0 = 101325 Pa. rho = P/(R*T) = 101325/(287.05287*288.15) = 101325/82714.2845 = 1.22500 kg/m^3. a = sqrt(gamma*R*T) = sqrt(1.4*287.05287*288.15) = sqrt(115799.998) = 340.294 m/s. sigma = rho/rho0 = 1.22500/1.22500 = 1.00000."
}

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-tranche6/tranche6-results.json