MTR390 is an active free-power-turbine turboshaft family developed collaboratively by MTU Aero Engines, Safran Helicopter Engines, and Rolls-Royce for the Airbus Helicopters Tiger. The MTR390-2C provides the baseline Tiger installation, while the MTR390-E adds 14 percent additional power; current MTU material documents the family’s helicopter application, variant boundary, and continuing support. Exact MTR390-2C/MTR390-E model identities and Tiger relationships remain separate records.