Lycoming O-540

O-540
AEIO-540
Type Certified Piston aircraft engine
National origin United States
Manufacturer Lycoming Engines
First run 1957
1963 (injected version)
Major applications Cessna 182
Cessna 206
Grob G 120
HAL HPT-32 Deepak
Piper PA-46
Robinson R44
Piper PA-31 Navajo
Tecnam P2012 Traveller
Embraer EMB 202 Ipanema
Produced 1957–present
Developed from Lycoming O-360

The Lycoming O-540 is a family of air-cooled six-cylinder, horizontally opposed fixed-wing aircraft and helicopter engines of 541.5 cubic inches (8,874 cc) displacement, manufactured by Lycoming Engines. The engine is a six-cylinder version of the four-cylinder Lycoming O-360.