1982 British Army Gazelle friendly fire incident On 6 June 1982 , during the Falklands War , the British Royal Navy Type 42 destroyer engaged and destroyed a British Army Gazelle helicopter , serial number " XX377 " , in a friendly fire incident , killing all four occupants . " Cardiff " , on the lookout for aircraft flying supplies to the Argentine forces occupying the Falkland Islands , had misidentified the helicopter as an enemy C - 130 Hercules . Although the helicopter ' s loss was initially blamed on enemy action , a subsequent inquiry found " Cardiff " s missiles to be the cause . On the night of 5 June , HMS " Cardiff " was stationed to the east of the islands to both provide gunfire support to the land forces and to intercept enemy aircraft . At around 02 : 00 a radar contact was detected ; a British Army Air Corps Gazelle helicopter was making a routine delivery of personnel and equipment to a radio rebroadcast station on East Falkland . From the contact ' s speed and course , " Cardiff " s operations room crew assumed it to be hostile . Two Sea Dart missiles were fired , destroying the target . The Gazelle ' s wreckage and crew were discovered the next morning , and the loss was attributed to enemy fire . Although " Cardiff " was suspected , later scientific tests on the wreckage proved inconclusive . No formal inquiry was held until four years later . Defending their claim that the helicopter had been lost in action , the United Kingdom ' s Ministry of Defence ( MoD ) stated that they had not wanted to " cause further anguish to relatives " while they were still trying to ascertain how the Gazelle had been shot down . The board of inquiry recommended that " neither negligence nor blame should be attributed to any individual " , but identified a number of factors . A lack of communication between the army and the navy meant that 5th Infantry Brigade had not notified anyone of the helicopter ' s flight . Conversely , the navy had not informed the land forces that " Cardiff " had changed position to set up an ambush for Argentine aircraft travelling over the area . Furthermore , the helicopter ' s Identification Friend or Foe ( IFF ) transmitter was turned off , because it caused interference with the army ' s Rapier anti - aircraft missile system . The board of inquiry ' s findings have prompted criticism of the MoD ' s initial response to the incident . Background . On 2 April 1982 , the disputed British overseas territory of the Falkland Islands was invaded by neighbouring Argentina . The United Kingdom , nearly away , assembled and dispatched a naval task force of 28 , 000 troops to recapture the islands . The conflict ended that June with the surrender of the Argentine forces ; the battles fought on land , at sea , and in the air had cost the lives of some 900 British and Argentine servicemen . In early May , British troops landed at San Carlos on the western side of East Falkland , and from there moved overland towards the islands ' capital of Stanley . To support the advance , logistical supplies were ferried to the troops by helicopter from San Carlos . The Argentine forces occupying Stanley were supplied throughout the war by C - 130 Hercules aircraft from the Argentine mainland . These " milk - runs " , as the British termed them , were a source of concern to the Royal Navy , and various attempts were made to intercept them . Incident . On the night of 5 June , the British Type 42 destroyer took up station on the " Bluff Cove Gunline " to the east of the islands . Tasked with a dual mission , " Cardiff " was to provide fire support to the marines of 3 Commando Brigade , and to interdict any Argentine aircraft attempting to fly into Stanley . The destroyer had performed a similar role four nights previously , when she unsuccessfully attempted to shoot down a resupply aircraft as it landed , and again as it took off . < ref name = " L / Cpl . S . J . Cockton " > < / ref > Meanwhile , pilots Staff Sergeant Christopher Griffin and Lance Corporal Simon Cockton , of 656 Squadron Army Air Corps , had been ordered to fly equipment and personnel to a malfunctioning radio rebroadcast station on top of Pleasant Peak . The station had been established the previous day to provide a communications link between the 5th Infantry Brigade headquarters at Darwin , and the 2nd Battalion , Parachute Regiment at Fitzroy . Night flying conditions were excellent , with a clear sky , a prominent moon and a wind speed of . The crew departed from Goose Green in Gazelle serial number " XX377 " and collected the replacement equipment from the headquarters at Darwin . They also took on board two passengers ; Major Michael Forge , the OC of 205 Signal Squadron , and one of his technicians , Staff Sergeant John Baker . Griffin was an experienced pilot ; the flight to the rebroadcast station was expected to take ten minutes . At 02 : 00 local time , " Cardiff " s operations room detected " XX377 " on her surface plot radar at a range of . The helicopter ' s Identification friend or foe ( IFF ) system was turned off , so receiving no friendly transmissions and with the contact apparently heading towards Stanley , the operations room crew assumed it to be hostile . After calculating its speed they believed they were tracking an Argentine fixed - wing aircraft — either a Hercules conducting a resupply mission , or a FMA IA 58 Pucará ground - attack aircraft sent to retaliate for " Cardiff " s shelling . " Cardiff " fired two of her Sea Dart missile s . 5th Infantry Brigade lost radio contact with the Gazelle , and simultaneously the exploding missile warheads were seen and heard by the rebroadcast station ' s personnel atop Pleasant Peak . " Cardiff " s crew were able to see the fireball , but only with the aid of night vision goggles . The helicopter ' s loss caused the British to suspect that Argentine forces were still operating in the area , so patrols were mounted by Gurkha soldiers . When the Gurkhas came across the personnel manning the Pleasant Peak station there was potential for another friendly fire incident to occur . At first light a proper search was carried out , and the Gazelle ' s wreckage was found along with the dead aircrew and passengers ; 5th Infantry Brigade ' s first casualties of the war . Immediately there were suspicions that " Cardiff " had been responsible for the shootdown , and later that evening Rear Admiral " Sandy " Woodward declared a " Weapons Tight " order , forbidding the engagement of any aircraft not positively identified as hostile , for all contacts detected flying over East Falkland at less than and under . Investigations . The crew ' s bodies were initially examined by senior medical officer , Rick Jolly . The helicopter ' s wreckage was inspected on - site , but the British were unable to determine if it had been destroyed by " Cardiff " s missiles or by Argentine fire . This uncertainty prompted the decision not to hold a board of inquiry , and " XX377 " was declared " lost in action " . It was surmised that , if the relatives of the deceased were told that the Gazelle might have been lost to friendly fire , it would add to their grief . After the war , missile fragments found in the wreckage were taken to the British government ' s aviation research facility at RAE Farnborough for analysis . The scientific tests concluded that the fragments were not from a British Sea Dart missile , despite a Sea Dart casing later being found " several hundred yards " away from the wreckage . In December 1982 an inquest was held by a Southampton coroner into the death of Lance Corporal Cockton after his body was repatriated to the UK . Based on RAE Farnborough ' s test results , the Army Air Corps submitted evidence stating that the analysis of the warhead fragments found in the wreckage indicated that the helicopter had been destroyed by a type of anti - aircraft missile " known to have been in the possession of the enemy " . The test results were reviewed in November 1985 and determined that there could be " no definitive conclusion as to the exact source of the missile fragments recovered from the crash site " . In June 1986 , John Stanley , the Minister of State for the Armed Forces , announced in his written answers to the House of Commons : " the [ Southampton ] coroner has been informed accordingly . " In October 1986 , partly due to pressure from Cockton ' s mother and the anti - war politician Tam Dalyell , an official board of inquiry was finally opened . The board took a month to reach the conclusion that " XX377 " was shot down by " Cardiff " . Historian Hugh Bicheno remarks : " It took [ the ] MoD four years and two investigations , the first either incompetent or a deliberate cover - up , even to admit the Gazelle blue - on - blue . " The board ' s findings were made public by a Freedom of Information Act request in July 2008 , although paragraph 13 of the report was redacted under section 26 of the act as it " contains operational details of the Royal Navy ' s activities , which , even with the passage of time since the Falklands campaign , would be of use to potential enemies . " The board of inquiry found that standard operating procedure dictated that the commanders of 5th Infantry Brigade were not required to declare the helicopter ' s mission to any other authority , as the flight was to occur in brigade airspace on a brigade task . Gazelle " XX377 " was equipped with an IFF transmitter , but this was turned off . In the opinion of the board , " had IFF been in use there is little doubt that Cardiff would not have engaged the aircraft that night . " At the time , less than half of the land force ' s helicopters were fitted with IFF transmitters , and those that were had been ordered not to use them because they inhibited the tracking systems of the British ground - based Rapier anti - aircraft missile batteries . A misconception about the Royal Navy ' s ability to engage air targets over land led to the navy not being informed that the army ' s helicopters were not using IFF . The board of inquiry concluded that it was this failure to communicate , together with the navy ' s assumption that all helicopters would be operating IFF , which " had a cumulative effect [ and ] was a major cause of [ the ] accident . " However , the board recommended that " neither negligence nor blame should be attributed to any individual " . Effects . Given that the role of helicopters in land force operations was increasing , as was the integration of guided missile destroyer s for coastal defence , the board of inquiry recommended an amendment to NATO procedures for amphibious warfare and naval gunfire support , to alert other armed forces to the danger of underestimating a ship ' s missile engagement zone over land . During the late 1980s , the British government placed more emphasis on joint warfare training , with exercises , such as Purple Warrior , taking place in Oman and Scotland . The board noted the establishment of the Permanent Joint Headquarters , designed to put an end to the " ad hoc and reactive way " in which operations had been carried out while under single service control . IFF transmitters were fitted to all Army Air Corps and Royal Marine Gazelle and Lynx helicopters , and the problem of operating IFF in the vicinity of Rapier batteries was successfully addressed . The board supported a recommendation that the responsibilities of naval gunfire - support liaison officers could be broadened to include the interpretation of air defence problems during inshore joint warfare operations . A memorial cross was installed atop Pleasant Peak , and the number " 205 " was painted at the crash site by the soldiers of 205 Signal Squadron . The number is approximately wide and can be seen from the air ( ) .