Bell UH - 1N Twin Huey The Bell UH - 1N Twin Huey is a medium military helicopter . The UH - 1N has a fifteen seat configuration , with one pilot and fourteen passengers . In cargo configuration the UH - 1N has an internal capacity of 220 ft³ ( 6 . 23 m³ ) . An external load of 5 , 000 lb ( 2 , 268 kg ) can be carried by the UH - 1N . It is currently being replaced in USMC service by the UH - 1Y . History . Based on the stretched fuselage Bell 205 , the Bell 212 was originally developed for the Canadian Forces ( CF ) under the designation CUH - 1N Twin Huey . Later the CF adopted a new designation system and the aircraft was re - designated as the CH - 135 Twin Huey . The CF approved the development of the aircraft on 1 May 1968 and purchased 50 aircraft , with deliveries commencing in May 1971 . The US military came very close to not procuring the Twin Huey . The purchase of the aircraft for US military use was opposed by the Chairman of the House Armed Services Committee at the time , L . Mendel Rivers . Rivers took this position because the aircraft powerplant , the Pratt & Whitney Canada PT6T was produced in Canada . The Canadian government had not supported US involvement in Vietnam and had opposed US policies in southeast Asia , as well as accepting US draft dodgers . Rivers was also concerned that procurement of the engines would result in a negative trade deficit situation with Canada . Congress only approved the purchase when it was assured that a US source would be found for the PT6T / T400 engines . As a result the United States military services ordered 294 Bell 212s under the designation UH - 1N , with deliveries commencing in 1970 . Unlike in the Canadian Forces , in US service , the UH - 1N retained the official name " Iroquois " from the single engined UH - 1 variants , although US service personnel refer to the aircraft as a " Huey " or " Twin Huey " . The Bell 412 is a further development of the Bell 212 , the major difference being the composite four - blade main rotor . The UH - 1N has also been developed into the upgraded , four - blade UH - 1Y . Design . The UH - 1N ' s main rotor is powered by a PT6T - 3 / T400 Turbo Twin Pac made up of two Pratt & Whitney Canada PT6 turboshaft power turbines driving a single output shaft . They are capable of producing up to 1 , 342 kW ( 1 , 800 shp ) . Should one engine fail the remaining engine can deliver 671 kW ( 900 shp ) for 30 minutes or 571 kW ( 765 shp ) enabling the UH - 1N to maintain cruise performance at maximum weight . The United States Marine Corps ( USMC ) modified a large number of their UH - 1Ns with a Stability Control Augmentation System ( SCAS ) which provides servo inputs to the rotor head to help stabilize the aircraft during flight . This modification removed the gyroscopic " Stabilization Bar " on top of the main rotor head , instead relying on the computer system for stability . Operational history . The United States Air Force employs UH - 1Ns to fulfill its ICBM mission , providing a utility helicopter for transport between bases such as Minot AFB , Francis E . Warren AFB and Malmstrom AFB to missile launch sites in North Dakota , Montana , Wyoming , Nebraska , and Colorado . The UH - 1N is also used by the 36th Rescue Flight ( 36 RQF ) at Fairchild AFB , WA for conducting Search - and - Rescue ( SAR ) and medical evacuation missions . On 6 March 1972 , Hendrick V . Gorick of the United States Navy Antarctic Development Squadron Six ( VXE - 6 ) jumped at an altitude of 20 , 500 ft ( 6 , 248 m ) from a UH - 1N helicopter . In doing so he set a record for parachute jumping over the Antarctic continent . During the 1982 Falklands War , the Argentine Air Force deployed two Bell 212 to Goose Green grass airstrip from where they performed general support duties including the recovery of many downed pilots . By the end of the hostilities both aircraft were still intact and both captured by the British . USMC UH - 1Ns were used by the USMC during its 2003 invasion of Iraq . UH - 1Ns provided reconnaissance , and communications support to Marine ground troops . They were also called upon to provide close air support during heavy fighting in Nasiriyah . Variants . U . S . variants . UH - 1N Iroquois VH - 1N HH - 1N UH - 1Y Venom Canadian variants . CUH - 1N Twin Huey CH - 135 Twin Huey Canada purchased 50 CH - 135s with deliveries starting in 1971 . The aircraft were retired from the Canadian Forces starting in 1996 and struck off strength in December 1999 . 41 of the surviving CH - 135s were acquired by the US government in December 1999 and transferred to the National Army of Colombia and Colombian National Police . At least one CH - 135 was destroyed in combat . 135135 was transferred to the Colombian National Police and flown by the Dirección Antinarcóticos ( DIRAN ) . It was destroyed on the ground by FARC rebels on 18 January 2002 , following an incident in which it was forced down by gunfire . Two CH - 135s are on display in museums , one at the Canada Aviation Museum in Ottawa and one at the National Air Force Museum of Canada at CFB Trenton . Italian - built variants . Agusta - Bell AB 212 Agusta - Bell AB 121EW Agusta - Bell AB 212ASW The AB - 212ASW is a Model 212 Twin Huey with a prominent radome above the cockpit . Early production had a dome - shaped radome , while later production had a flatter " drum " radome . A left side winch is used for dipping the Bendix ASQ - 18 sonar . Other changes include structural reinforcement for a gross weight of 11 , 197 lbs ( 5080 kg ) , ECM , shipboard deck tie - down attachments and corrosion protection . Armament is two Mk 44 or Mk 46 torpedoes or two depth charges in the ASW role and four AS . 12 air - to - surface wire - guided missiles for the anti - shipping role .