At least six people including three Russian pilots were killed on Saturday when a chartered helicopter crashed in north-western Pakistan due to engine failure, officials said. The incident occurred in North Waziristan district of the Khyber Pakhtunkhwa near the Afghan border. Another eight people were wounded in the accident. The MI-8 chartered helicopter was providing personnel transportation services to Mari Petroleum Company Limited (MPCL). “MPCL chartered MI-8 Helicopter carrying 14 passengers including three foreign (Russian) pilots while flying in North Waziristan crashed landed close to…