Boeing Vertol Ch-46 Sea Knight

Twin Rotorcraft

The Boeing Vertol CH-46 Sea Knight is a tandem-rotor medium-lift helicopter that served as the U.S. Marine Corps' primary assault transport for over four decades, from the Vietnam War through 2015. Developed in the late 1950s as a commercial design (Model 107), it was adopted by the military and became one of the most recognizable twin-rotor helicopters in American service, capable of carrying 25 combat troops or 10,000 pounds of cargo in its distinctive banana-shaped fuselage. The tandem-rotor configuration eliminates the need for a tail rotor, providing exceptional stability in hover and allowing the aircraft to maintain control even with one engine failed—a critical safety feature for overwater operations and shipboard deployment. While the military retired its last CH-46E in 2015, a small number of civilian variants continue operating in demanding commercial roles. Columbia Helicopters, the world's leading operator of heavy-lift helicopters, maintains a fleet of former military CH-46s converted for firefighting, logging, and construction support. These aircraft excel at external load operations in mountainous terrain, where their 12,000-pound hook capacity and high-altitude performance prove invaluable. The type's twin General Electric T58 turboshaft engines provide redundancy and power reserves that remain competitive with more modern designs for specialized missions. The CH-46's operational envelope includes a never-exceed speed of 165 knots and a service ceiling around 14,000 feet, though performance varies significantly with external loads and density altitude. Its ability to maintain controlled flight on a single engine—rare among helicopters of this size and era—made it exceptionally safe for the shipboard and combat operations that defined its military career. Today's civilian operators value the same ruggedness and payload capacity that made the Sea Knight a Marine Corps workhorse for half a century. SkyMeter has tracked 2 flights across 2 airframes and 1 operators, with COLUMBIA HELICOPTERS INC the largest observed operator.