Experimental Military Unit The Experimental Military Unit ( EMU ) was a company - sized helicopter assault force which operated during the Vietnam War . The EMU was created by the integration of a contingent of Royal Australian Navy ( RAN ) aviation personnel ( known as the RAN Helicopter Flight Vietnam or RANHFV ) into the United States Army ' s 135th Assault Helicopter Company . Organisation and role . The EMU was formed around the US Army ' s 135th Assault Helicopter Company . The 135th had previously flown Caribou transports as a tactical air transport company , but was reoriented for helicopters following the Johnson - McConnell agreement of 1966 , when all fixed - wing aircraft were transferred to the United States Air Force and all rotary - wing aircraft to the United States Army . The 135th was integrated with the Royal Australian Navy Helicopter Flight Vietnam , an Australian contingent of eight pilots , four observers , four aircrew , twenty - four technical sailors and mechanics , and six administrative personnel , all drawn from 723 Squadron RAN . Four of these contingents were deployed during the Australian participation in the joint unit ( RANHFV 1 through 4 ) . The Australian officer in charge of the RAN contingent became the executive officer of the 135th Company , and because of their more extensive training and experience when compared to the American personnel ( for example , one US Army flying instructor assigned to the company had only 125 hours flying experience , while each RAN pilot had over 1 , 000 hours ) , Australian personnel commonly filled out leadership positions throughout the company . The collective name for the combined unit was the Experimental Military Unit , or EMU . The name was a backronym for emu , and was selected by the 135th before their deployment for being a large , fast , and highly mobile Australian bird . However , the designation amused Australian members of the company , because emus cannot fly . The EMU was officially part of 12th Aviation Group , 1st Aviation Brigade , and was part of the US Army chain of command . A separate chain of command for RAN personnel was maintained to the Commander Australian Forces Vietnam . The Australian command chain was rarely used : David Farthing , who led RANHFV 3 , claims he only had to use it once during his twelve - month deployment . The main role of the EMU was to provide transport and support for units of the Army of the Republic of Vietnam ( ARVN ) , United States Army and Marine Corps , and Australian Army . For this purpose , the company was equipped with UH - 1 Iroquois helicopters : thirty UH - 1D or UH - 1H ' Slick ' troop - carrying helicopters ( the EMU was the first Assault Helicopter Company to be equipped with the ' H ' model ) , and eight UH - 1C gunship helicopters ( nicknamed Taipans , after the venomous Australian snake ) . The company was divided up into five platoons : two troop transport , one gunship , one maintenance , and one headquarters . A typical daily deployment consisted of ten Slicks ( plus a spare ) , two teams of two gunships , and a Command and Control helicopter ( designated ' Charley Charley ' ) . The helicopters would depart base at dawn , collect a unit ( typically from the United States 9th Infantry Division , the United States 199th Infantry Brigade , the South Vietnamese III and IV Corps , or the 1st Australian Task Force ) , perform a combat assault , then return the unit to their base before dark . Other duties performed by the EMU , particularly from 1970 onwards , included dawn and dusk assaults ; night hunter - killer patrols , which consisted of one Slick armed with flares , two gunships , and a Charley Charley armed with a high - power searchlight and a twin 0 . 50 calibre machinegun ; and joint operations with the United States Navy SEALs , which typically involved locating and capturing senior Viet Cong personnel . History . Creation . In 1966 , the United States requested that Australia send more helicopter pilots to Vietnam , as the increase in the number of US and allied soldiers had increased beyond the capability of helicopter transport and support units . Because of Australian Army and Royal Australian Air Force ( RAAF ) commitments in Vietnam and elsewhere , the only available pilots were from the RAN Fleet Air Arm . It was originally intended to integrate them with the Royal Australian Air Force ' s No . 9 Squadron , although the United States Army requested that the RAN pilots be integrated with one of their helicopter companies . On 14 July 1967 , it was announced that the RAN Helicopter Flight Vietnam ( RANHFV ) would be created and combined with the US Army ' s 135th Assault Helicopter Company to form the Experimental Military Unit ( EMU ) . October 1967 – September 1968 . The components of the EMU arrived in Vung Tau during early October 1967 : the 135th during the first week , and the RANHFV contingent during 16 – 18 October . The company was declared operational on 3 November 1967 . The company operated from Vung Tau during November and December , then was relocated to Blackhorse Camp ( operating base of the 11th Armored Cavalry Regiment ) in the Xuân Lộc district on 31 December . In mid - February , while delivering the 9th Division to a landing zone near Mỹ Tho , the EMU encountered multiple companies of heavily armed North Vietnamese soldiers . One helicopter was shot down by a rocket , killing the American aircrew , and eight other aircraft were damaged . On 22 February 1968 , a RAN EMU pilot was killed while leading a mission to extract South Vietnamese soldiers from a Viet Cong assault . He was the first Australian pilot to be killed in the Vietnam War . A program started in late February , where pilots from No . 9 Squadron RAAF were invited to fly with the EMU for two - week stints : although officially conceived to promote knowledge - sharing between the Royal Australian Navy , Royal Australian Air Force , and the United States Army aviation branch , the plan also helped counteract pilot shortages in the EMU as United States personnel completed their twelve - month draft period and were not immediately replaced . On 18 May , the EMU was assigned to transport the South Vietnamese 25th Division . During the landing , the force was ambushed by Viet Cong soldiers : ten aircraft were hit and several South Vietnamese were killed or wounded , although the only injury suffered by EMU aircrew was a bullet through the earlobe of an American pilot . It was later found that the attack resulted from an intelligence leak withitn the South Vietnamese unit , resulting in a tightening of procedures and the creation of ' Smoky ' ; an Iroquois modified to generate a smoke screen during landings . On 21 August , a gunship was struck by a rocket and crashed , killing the three aircrew . Starting from 9 September , the second RANHFV contingent was rotated in , with the EMU ' s Australian Executive Officer relieved on 30 September , and the last members of the first contingent departing on 15 October . During RANHFV 1 ' s deployment , the EMU had flown 30 , 670 hours , with seven American and three Australian aircrew killed , plus eleven Americans and four Australians seriously injured . October 1968 – September 1969 . On 23 October , the EMU met heavy resistance near Bến Tre while performing insertions and extractions of the 9th Division . Two helicopters crashed and were destroyed , and another seven damaged , but there were no aircrew casualties . From November , the EMU was assigned to operate from Bear Cat Camp ( operating base of the 222nd Aviation Battalion ) near Biên Hòa , at the same time as their duties expanded to include supporting Royal Thai Army forces . In January 1969 , a RAN pilot was killed when his helicopter made contact with power lines during bad weather . In mid - February , a gunship was shot down in Vĩnh Long by a Viet Cong force . The aircrew survived , and used the gunship ' s door - mounted M60 machine gun s to keep the Viet Cong soldiers at bay until another EMU helicopter could rescue them . The Viet Cong commenced sporadic mortar attacks on Bear Cat on 22 February , forcing the EMU to evacuate their helicopters and support personnel to Blackhorse six times over the next seven days . On 31 May , an EMU gunship escorting a formation near Đồng Tâm came under heavy fire and crashed , killing all aboard . On 16 June , an Australian gunner aboard a Slick was wounded while providing covering fire for a medical evacuation of South Vietnamese soldiers near Cái Bè . Despite the start of the wet season in June , North Vietnamese activity increased . This , combined with the loss of several helicopters and the replacement of the US 9th Infantry Division with the less professional South Vietnamese 7th and 9th Divisions as part of the ' Vietnamization ' process , increased the EMU ' s workload . RANHFV 3 began to rotate in from 10 September , and was completed by late September . October 1969 – September 1970 . On 19 December , following a Viet Cong ambush in Bình Đại which killed half of a South Vietnamese unit , the EMU successfully deployed a blocking force in the path of the North Vietnamese withdrawal , which inflicted heavy casualties . Several helicopters were shot down and crew chiefs killed or wounded during operations in the first months of 1970 . Around the same time , the replacement of South Vietnamese commanders with more aggressive officers in the units the EMU operated with , a desire to prevent North Vietnam from launching another Tet Offensive - like attack , and the commencement of nighttime hunter - killer patrols dramatically increased the EMU ' s workload . This was compounded by shortages in new American personnel to replace those who had completed their draft , spare parts , and aircraft , forcing the EMU to borrow helicopters and aircrew from other units . In early March , an EMU helicopter landed on a booby trap , seriously wounding the Australian pilot and killing two South Vietnamese passengers . Later that month , an American gunship aircrewman died from wounds received from enemy fire , while in a separate incident , five Slicks were damaged by gunfire . At the start of May 1970 , the EMU was marked to lead operations into Cambodia . However , as Australian personnel were forbidden by their rules of engagement from entering Cambodia , a point reinforced by the Australian Embassy the night before the first operation , the EMU was forced to operate without Australian personnel for several days , until they were re - assigned to duties in Vietnam . The commitment of other helicopter units to the Cambodian campaign further increased the EMU workload . On 18 May , a South Vietnamese outpost was overrun by a Viet Cong battalion . The EMU was called in to drop counterattacking troops into the area ; during this the Australian - manned lead helicopter was damaged and had to withdraw . Another EMU helicopter was diverted from other operations to lead the insertions . The second leader received cockpit instrument damage from enemy fire , although the Australian pilot remained on station for several more waves . The pilot was later awarded the United States Silver Star , the South Vietnamese Cross of Gallantry , and was mentioned in despatches . Two days later , an EMU gunship crashed after being fired on by a . 50 caliber machine gun , killing the American aircrew , while its companion was heavily damaged . By the end of May , the shortage of United States personnel had been addressed , with the company brought back to full strength . However , the gunship platoon was down several helicopters , a situation that remained unaddressed as the UH - 1C gunship was no longer in production , and the replacement , the AH - 1 Cobra , had not been deployed to frontline units . In August , the EMU was relocated to a base at Đồng Tâm , which also housed elements of the United States Navy SEALs and the Mobile Riverine Force . Although closer to the unit ' s normal operating areas ( an advantage which was negated when the 21st Division , operating in the Mekong Delta began to require EMU support ) , the base was regularly subjected to mortar and rocket attacks ( in the first month , the base was mortared on average once a week ) . The EMU was required to relocate completely within four days while continuing operations . The Royal Australian Navy rotation from RANHFV 3 to RANHFV 4 occurred during September , with the EMU executive officer position formally handed over on 17 September . October 1970 – June 1971 . Attacks on the base continued throughout October and November ; five EMU personnel were wounded by mortar shrapnel on 3 November . On 11 November , the EMU was required to drop four waves of South Vietnamese soldiers into an engagement with a Viet Cong battalion near U Minh . During this , five aircraft were damaged , one of which was forced to land , but later recovered . The vulnerability of the UH - 1 Iroquois was demonstrated in late 1970 , when five EMU helicopters were shot down in the Kien Hoa province by a single Viet Cong soldier armed with an AK - 47 rifle . Nobody was killed in the resulting crashes , but all five helicopters had to be airlifted out by CH - 47 Chinook s . On 4 December , an Australian EMU pilot rescued a South Vietnamese patrol boat , which had been disabled and was drifting towards the Viet Cong force that had attacked it and sunk a companion craft . Despite coming under fire , the pilot achieved this by entangling his Iroquois ' landing skids in the boat ' s superstructure and towing it away ; he was later awarded the Distinguished Flying Cross for his actions . Operations continued into the new year , and on 16 January 1971 an EMU helicopter was shot down , crashing upside - down . The American pilot was killed , but the other personnel survived the crash , linked up with South Vietnamese troops fighting in the area , and remained with them until helicopters of the 1st Cavalry Regiment drove the North Vietnamese off . During late February and early March , South Vietnamese and American forces were involved in Operation Lam Son 719 , an attempt to cut North Vietnamese supply lines ( known as the Ho Chi Minh trail in Laos . Because of the Australian contingent , the EMU did not participate in this operation , but found that American pilots and aircrew intended for the unit to replace draft completers were instead being diverted to helicopter companies supporting the operation . Early in 1971 , it was announced that the RANHFV would be one of several Australian units to withdraw from Vietnam by mid 1971 . The Australian personnel of the EMU ceased flying operations on 8 June , and departed on 16 June , marking the end of the joint - force Experimental Military Unit . Awards and honours . The Australian personnel received a number of honours and decorations : three were appointed Member of the Order of the British Empire ( MBE ) , eight received the Distinguished Service Cross ( DSC ) , five the Distinguished Flying Cross ( DFC ) , and one received the British Empire Medal ( BEM ) . Twenty four were Mentioned in Despatches , and thirty four received Naval Board Commendations . This was over half of the honours and awards presented to RAN personnel serving in the Vietnam War . Australian personnel were also awarded several Vietnamese and United States decorations . 723 Squadron RAN , the parent unit of the RAN Helicopter Flight Vietnam , was awarded the battle honour " Vietnam 1967 – 71 " . Five RAN personnel assigned to the EMU were killed during the conflict , with another ten seriously injured : the highest casualty rate of any RAN unit in Vietnam .