Test Flight (Mod)

TestFlight adds 2 main mechanics: semi-random failures and maximum burn times to all engines.

Engine failures are not completely random but depend on your engines current research/test rate. Each engine has by default 0 Data Units (Du) when you first unlock it. The maximum Du you can have per engine is 10.000. Du increase engine reliability. But even a fully researched/tested engine (with 10.000 Du) will still have some chances to fail. This risk is different per engine. For example, the early WAC engine has more chances to fail than the XSAR. You can assign R&D teams (in exchange for cash) to provide an initial boost to your Du, this has a limit though: you can not fully research an engine just like this. The main solution to increase the Data Units of your engines is to use them, on real rockets. Note that Data Units will only start to add up when the launch clamps are released: you can not test an engine just by igniting it on the launchpad without really launching your rocket.

All engines have a maximum rated burn time. If your engine is rated for maximum burn of 2 minutes, keeping it burning after this will gradually increase the risk of it to fail. Early engines often have a pretty high failure rate. Meaning your very first flights (before they are fully tested) will almost all have engine failures. More modern engines usually have much better reliability. Note that during ignition, the failure rate is also higher than during the rest of the burn time. Incidently, having an engine failure (wheather it is a partial failure as a 'Loss of thrust' or a full failure as 'engine exploding' or 'engine shutdown') is actually beneficial, as hundreds of Data Units will be earned when an engine fails. Your engineers will learn from those failures, enabling them to build this engine more reliably next time.

All engines have specific failure rates, maximum burn times an reliability. All these values are based of real world data available for these engines.

For engines having upgraded versions of the same engine, if you already gathered Data on the lower tier engine, you will already have some Du available for the new version even if you never test it before.

If you are using KRASH mod to simulate launches, you may want to temporarly disable TestFlight to be able to simulate your rocket launch without a risk for it to make your engines fail. This is possible in TestFlight options while in-game in the flight scene. Even if kept turn on, Data Units gathered in the simulation of KRASH will be lost when the simulation is over.

TestFlight enforces you to use the same engines as much as possible, as the more you have used an engine the more chance you have for it not to fail.