01 Validation Certified engine data

How wrong is it?

Every simulator should be able to answer that. This one is checked against 26 real engines whose fuel consumption is a matter of public certification record — from a 1968 Spey to a geared turbofan of 2016. The numbers below are computed live by the same solver the console runs, and every error is shown, including the ones that do not flatter the model.

CONCEPT · WHAT MAKES THIS VALIDATION AND NOT CURVE-FITTING
The ICAO Aircraft Engine Emissions Databank publishes each engine's certified thrust and fuel flow. Their ratio is a fuel consumption figure PropulsionLab had no hand in producing. What the databank does not publish — turbine temperature, component efficiencies — is supplied by one fixed assumption set applied identically to all 26 engines. Nothing is fitted per engine. A model that agrees only after being tuned engine by engine has demonstrated nothing at all, so the disagreement that costs is reported here rather than removed.

Predicted against certified

Sea-level static takeoff
One engine Perfect agreement (1:1)

Every case

Sorted by bypass ratio
Engine BPROPRTt4 assumed Certified TSFCPropulsionLabError
Running 26 engines through the solver…

TSFC in lb of fuel per lbf of thrust per hour. Error is signed: positive means PropulsionLab predicts more fuel burn than the engine was certified at. Turbine temperature is assumed, not published — see below.

The shared assumption set

Applied identically to every engine on this page. Turbine inlet temperature is the one exception to being a single constant: it is tied to each engine's published pressure ratio, because a single value across five decades is knowingly unphysical — held at 1500 K, three of the modern engines have no solution at all, since a bypass-11 fan cannot be driven by a turbine that cold. The relation is anchored to historical practice and was fixed before any error was computed.

What is and is not validated

Validated

Not validated

Where the numbers come from

Check it yourself

Reference data: ICAO Aircraft Engine Emissions Databank, read in machine-readable form via the OpenAP engine table (TU Delft). Every row above keeps its ICAO engine UID, so any figure can be looked up against the primary source without going through this site at all. The report itself is served live at /validation/report, and scripts/build_validation_set.py in the repository regenerates the case file from scratch.