Honeywell TPE331

The Honeywell TPE331 is a turboprop engine from Honeywell Aerospace, in service since 1961. The Honeywell TPE331 (originally Garrett TPE331) is one of the most widely used turboprop engines in general aviation, powering a broad range of single and twin-engine aircraft since the 1960s. Unlike free-turbine engines, the TPE331 uses a direct-drive architecture with a fixed-shaft turbine connected to the propeller gearbox, providing excellent torque response. Power ratings range from 575 to 1,650 shp across the numerous variants in the TPE331 family.

It powers aircraft such as the Beechcraft King Air 90, Cessna Conquest, Fairchild Merlin, Mitsubishi MU-2 and others. When buying or overhauling a turboprop like this, the figures that matter most to operators are time since overhaul, program enrolment (engine maintenance program vs time-and-material), and the cost of the next shop visit — all of which a seller quote should make clear.