The Russian air force grounded its entire fleet of Sukhoi-27 fighter jets on Thursday after a fatal crash near Moscow which aviation sources told Russian agencies looked like the result of some kind of technical failure. Viktor Bondarev, the head of the air force, ordered the country's fleet of the twin-engined fighter jet grounded until the reasons for the crash had been determined, Russian agencies reported. Russia is believed to have over 300 of the fighter jets in service. The United States complained in April that one of them had made aggressive manoeuvres near a U.S. reconnaissance plane over the...