A Mil Mi-8 helicopter was shot down on 21 April about 20km (12 miles) north of the Iraqi capital Baghdad, killing all 11 people on board. US and Bulgarian officials say the aircraft, owned by a Bulgarian company Heli Air and chartered by Canadian company SkyLink, was brought down by a rocket-propelled grenade. On board were six US security contractors, three Bulgarian crew members and two Fijian security guards.