Boeing Vertol CH - 46 Sea Knight The Boeing Vertol CH - 46 Sea Knight is a medium - lift tandem rotor transport helicopter . It is used by the United States Marine Corps ( USMC ) to provide all - weather , day - or - night assault transport of combat troops , supplies and equipment . Additional tasks include combat support , search and rescue ( SAR ) , support for forward refueling and rearming points , CASEVAC and Tactical Recovery of Aircraft and Personnel ( TRAP ) . The Sea Knight was also the U . S . Navy ' s standard medium - lift utility helicopter until it was phased out in favor of the MH - 60S Knighthawk in the early 2000s . Canada also operated the Sea Knight , designated as CH - 113 , and operated them in the SAR role until 2004 . Other export customers include Japan , Sweden , and Saudi Arabia . The commercial version is the BV 107 - II , commonly referred to simply as the " Vertol " . Development . Origins . Piasecki Helicopter was a pioneering developer of tandem - rotor helicopters , with the most famous previous helicopter being the H - 21 " Flying Banana " . Piasecki Helicopter became Vertol in 1955 and work began on a new tandem rotor helicopter designated the " Vertol Model 107 " or V - 107 in 1956 . The V - 107 prototype had two Lycoming T53 turboshaft engines , producing 877 shp ( 640 kW ) each . The first flight of the V - 107 took place on 22 April 1958 . The V - 107 was then put through a flight demonstration tour in the United States and overseas . In June 1958 , the U . S . Army awarded a contract to Vertol for ten production aircraft designated " YHC - 1A " . The order was later decreased to three , so the U . S . Army could divert funds to the V - 114 , also a turbine powered tandem , but larger than the V - 107 . The Army ' s three YHC - 1As were powered by GE - T - 58 engines . The YHC - 1As first flew in August 1959 , and were followed by an improved commercial / export model , the 107 - II . During 1960 , the U . S . Marine Corps evolved a requirement for a twin - turbine troop / cargo assault helicopter to replace the piston engine types then in use . Following a design competition , Boeing Vertol was selected to build its model 107M as the HRB - 1 , early in 1961 . Boeing had acquired Vertol in 1960 and renamed the group Boeing Vertol . In 1962 the U . S . Air Force ordered 12 XCH - 46B Sea Knights with the " XH - 49A " designation . but later cancelled the order due to a delay in the delivery schedule . They opted for the Sikorsky S - 61R instead . The Sea Knight was first procured in 1961 by the U . S . Marine Corps to meet their medium - lift requirements . Its first flight in August 1962 was followed by a change in designation to CH - 46A . Fleet introduction of CH - 46As with the Marines and the Navy ' s UH - 46As was in November 1964 . The UH - 46A variant was modified for use in the vertical replenishment role . The CH - 46A was equipped with a pair of T58 - GE8 - 8B turboshaft engines rated at 1 , 250 shp ( 930 kW ) each and could carry 17 passengers or 4 , 000 pounds ( 1 , 815 kg ) of cargo . Further developments . Production of the improved CH - 46D followed with deliveries beginning in 1966 . Its improvements included modified rotor blades and more powerful T58 - GE - 10 turboshaft engines rated at each . The increased power allowed the D - model to carry 25 troop or of cargo . The CH - 46D was introduced to the Vietnam theater in late 1967 , supplementing the U . S . Marine Corps ' existing unreliable and problematic CH - 46A fleet . Along with the USMC ' s CH - 46Ds , the U . S . Navy received a small number of UH - 46Ds for ship resupply . Also , approximately 33 CH - 46As were upgraded to CH - 46Ds . The Marines also received CH - 46Fs from 1968 to 1971 . The F - model retained the D - model ' s T58 - GE - 10 engines but revised the avionics and included other modifications . The CH - 46F was the final production model . The Sea Knight has undergone upgrades and modifications . Most of the U . S . Marine Corps ' Sea Knights were upgraded to CH - 46E standard . The CH - 46E features fiberglass rotor blades , airframe reinforcement , and further uprated T58 - GE - 16 engines producing each . Some CH - 46Es have been given doubled fuel capacity . The Dynamic Component Upgrade ( DCU ) incorporated starting in the mid - 1990s provides for increased capabilities through strengthened drive systems and rotor controls . The commercial variant , the " BV 107 - II " , was first ordered by New York Airways in 1960 . They took delivery of their first three aircraft , configured for 25 passengers , in July 1962 . In 1965 , Boeing Vertol sold the manufacturing rights of the 107 to Kawasaki Heavy Industries . Under this arrangement , all Model 107 civilian and military aircraft built in Japan are known as " KV 107 " . On 15 December 2006 , Columbia Helicopters , Inc acquired the type certificate for the Boeing Vertol 107 - II , and is in the process of acquiring a Production Certificate from the FAA . Plans for actual production of the aircraft have not been announced . Design . The CH - 46 has tandem contrarotating rotors powered by two GE T58 turboshaft engines . The engines are mounted on each side of the rear rotor pedestal with a driveshaft to the forward rotor . The engines are coupled so either could power both rotors in an emergency . The rotors feature three blades and can be folded for on - ship operations . The CH - 46 has fixed tricycle landing gear , with twin wheels on all three units . The gear configuration causes a nose - up stance to facilitate cargo loading and unloading . The main gear are fitted in rear sponsons that also contain fuel tanks with a total capacity of 350 US gallons ( 1 , 438 L ) . The CH - 46 has a cargo bay with a rear loading ramp that could be removed or left open in flight for extended cargo or for parachute drops . An internal winch is mounted in the forward cabin and can be used to pull external cargo on pallets into the aircraft via the ramp and rollers . A belly sling hook ( cargo hook ) which is usually rated at . could be attached for carrying external cargo . Although the hook is rated at . , the limited power produced by the engines preclude the lifting of such weight . It usually has a crew of three , but can accommodate a larger crew depending on mission specifics . For example , a Search and Rescue variant will usually carry a crew of five ( Pilot , Co - Pilot , Crew Chief , Swimmer , and Medic ) to facilitate all aspects of such a mission . A pintle - mounted 0 . 50 in ( 12 . 7 mm ) Browning machine gun is mounted on each side of the helicopter for self - defense . Service in southeast Asia resulted in the addition of armor with the guns . Operational history . United States . Known colloquially as the " Phrog " , the Sea Knight has been used in all U . S . Marine combat and peacetime environments since its introduction . As of 2011 , it is still regularly flown by the U . S . Marine Corps , its longevity as a reliable airframe has led to such mantras as " phrogs phorever " and " never trust a helicopter under 30 " . CH - 46E Sea Knights were used by the U . S . Marine Corps during the 2003 invasion of Iraq . CH - 46Es transported personnel , brought supplies to forward arming and refueling points ( FARP ) , carried ammunition and various tasks . Marine CH - 46Es and CH - 53Es carried U . S . Army Rangers and Special Operations troops in a mission to extract captured Army Private Jessica Lynch from an Iraqi hospital on 1 April 2003 . While the United States Navy retired the airframe on 24 September 2004 , replacing it with the MH - 60S Knighthawk , the Marine Corps plans to maintain its fleet until the MV - 22 is fully fielded . In March 2006 Marine Medium Helicopter Squadron 263 ( HMM - 263 ) was deactivated and redesignated VMM - 263 to serve as the first MV - 22 squadron . The replacement process is expected to continue through the other medium helicopter squadrons into 2014 . Canada . The Royal Canadian Air Force procured six CH - 113 Labrador helicopters for the SAR role and the Canadian Army acquired 12 of the similar CH - 113A Voyageur for the medium - lift transport role . The RCAF Labradors were delivered first with the first one entering service on 11 October 1963 . When the larger CH - 147 Chinook was procured by the Canadian Forces in the mid - 1970s , the Voyageur fleet was converted to Labrador specifications to undertake SAR missions . The refurbished Voyageurs were re - designated as CH - 113A Labradors , thus a total of 15 Labradors were ultimately in service . The Labrador was fitted with a watertight hull for marine landings , a 5 , 000 kilogram cargo hook and an external rescue hoist mounted over the right front door . It featured an 1 , 110 kilometer flying range , emergency medical equipment and an 18 person passenger capacity . By the 1990s , heavy use and hostile weather conditions had taken their toll on the Labrador fleet , resulting in increasing maintenance costs and the need for prompt replacement . In 1981 , a mid - life upgrade of the fleet was carried out by Boeing Canada in Arnprior , Ontario . Known as the SAR - CUP ( Search and Rescue Capability Upgrade Program ) , the refit scheme included new instrumentation , a nose - mounted weather radar , tail - mounted auxiliary power unit , a new high - speed rescue hoist mounted over the side door and front - mounted searchlights . A total of six CH - 113s and five CH - 113As were upgraded with the last delivered in 1984 . In 1992 it was announced that the Labradors were to be replaced by 15 new helicopters , a variant of the AgustaWestland EH101 , designated " CH - 149 Chimo " . The order was subsequently cancelled by the Jean Chrétien Liberal government in 1993 , resulting in cancellation penalties , as well as extending the service life of the Labrador fleet . However , in 1998 , a CH - 113 from CFB Greenwood crashed on Quebec ' s Gaspé Peninsula while returning from a SAR mission , resulting in the deaths of all crewmembers on board . The crash placed pressure upon the government to procure a replacement , thus an order was placed with the manufacturers of the EH101 for 15 aircraft to perform the search - and - rescue mission , designated " CH - 149 Cormorant " . CH - 149 deliveries began in 2003 , allowing the last CH - 113 to be retired in 2004 . In October 2005 Columbia Helicopters of Portland , Oregon purchased eight of the retired CH - 113 Labradors to add to their fleet of 15 Vertol 107 - II helicopters . Sweden . In 1963 , Sweden procured 10 UH - 46B from the US as a transport and anti - submarine helicopter for the Swedish armed forces , designated Hkp4A . In 1973 , a further 8 Kawasaki - built KV - 107 , which were accordingly designated Hkp4B , were acquired to replace the older Piasecki H - 21 . During the Cold War , the fleet ' s primary missions were anti - submarine warfare and troop transportation , they were also frequently employed in the search and rescue role . In the 1980s , the Hkp4A was phased out , having been replaced by the Eurocopter AS332 Super Puma ; the later Kawasaki - built Sea Knights continued in operational service until 2011 , they were replaced by the UH - 60 Black Hawk . Civilian . The civilian version , designated as the BV 107 - II " Vertol " , was developed prior to the military CH - 46 . It was operated commercially by New York Airways , Pan American World Airways and later on by Columbia Helicopters . In December 2006 , Columbia Helicopters purchased the type certificate of the Model 107 from Boeing , with the aim of eventually producing new - build aircraft themselves . Variants . Japanese versions . Source :