The US Marine Corps' (USMC) Boeing-built CH-46 Sea Knight medium-lift assault helicopter has retired from service after completing its last flight, conducted by Reserve Marine Medium Helicopter Squadron (HMM) 774.

The CH-46 Sea Knight helicopter, commonly known as the Phrog, served the US Navy and USMC medium-lift assault community.

The helicopter was maintained by the Specialized and Proven Aircraft Program Office (PMA-226) at Marine Corps Station Cherry Point, offering critical modifications to sustain the aircraft to retirement.

PMA-226 deputy programme manager Andy Wilkinson said: "The CH-46 has been on the front line in most every Marine Corps military action in the last 50 years putting troops on the enemy front lines, delivering critical supplies, rescuing wounded service members on the battle field, and performing humanitarian assistance and disaster relief in response to tragedies around the world."

Launched in 1964 as a commercial aircraft, the CH-46 was later converted to support assault, cargo, and search and rescue roles to replace the H-34 helicopter in Vietnam.

"HMM-774's redesignation as Marine Medium Tiltrotor Squadron (VMM) 774 marks the end of the H-46's service in the Marine Corps."

A statement from the USMC read as: "The CH-46 Sea Knight has faithfully served the Corps for more than half a century.

"HMM-774's redesignation as Marine Medium Tiltrotor Squadron (VMM) 774 marks the end of the H-46's service in the Marine Corps, as well as its presence in the skies above Norfolk."

The USMC will now replace the CH-46 Sea Knight with the MV-22 Osprey, a joint-service, medium-lift, multi-mission tilt-rotor aircraft, developed by Boeing and Bell Helicopters.

The new aircraft operates as a helicopter when taking off and landing vertically. The nacelles rotate 90° forward once airborne, converting it into a turboprop aircraft.

Image: A US Marine Corps CH-46 Sea Knight medium-lift assault helicopter. Photo: courtesy of Andrew Schmidt.