| Thrust ratings are a thing. They’re “programmed” using a dummy plug. Literally an electrical connector that has a cap on it and inside that cap is a bunch of wires that loop back and bridge pins. The pin combo represents a thrust rating.
The plug is set and screwed into the fadec at manufacture and then updated after each service based on the test cell run. Overhaul is often defined in terms of thrust ratings. Customers engine comes in, dyno’d (test cell) current thrust level is established. A plan is put to the customer based on their requirements, work is then done, dyno’d again and then signed off with the new plug installed. Why would you do this? When engines are made, from automotive engines through to sophisticated jet engines, they all have a rated power number but minor variations in tolerances etc add up to make the actual power number. In a jet engine, you have two or more on a plane, if one engine is slightly more powerful the plane will naturally try to fly in circles. I think the parent comment gets a lot of things confused, for example you don’t rent a thrust rating.
You rent an engine, at a thrust rating and will need to return it at that same thrust rating after you’re done (ie a mandatory overhaul of the engine and scoped to a particular rating). Often the engines are owned by leasing companies or banks. Have a look next time you fly, there may just be a “Bank of Honk Kong” sticker on the side of your engine. |