[progman32]

You're telling me that there are devices built into civilian airplanes that are able to disable or hobble the engines based on the whims of _business agreements_? It seems beyond reason that a pilot would be denied an engine's full design thrust, especially in a contingency that requires as much performance as possible (terrain avoidance, wind shear, aerodynamic surface failures, engine flameouts, on-ground emergencies after takeoff decision speed, go-arounds, etc...) Can you expand a bit on how this system works? Do you know what prevents a mistyped lease expiry date from causing dangerous incidents?

I hope it's fully airgapped at the very least...!

[rocqua]

https://airleasereviewblog.com/2016/06/19/engine-thrust-at-d...

It seems like a system that can't be easily changed mid flight and it's leased from the manufacturer as an alternative to buying the 'upgrade'.

[aunty_helen]

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.

[progman32]

That makes sense and is much closer to how I understood things. Parent comment made it sound to me like there is a whole subsystem dedicated to plane DRM.