Bomb scare at Shah Amanat International Airport in the port city yesterday kept a Dubai-bound Biman Bangladesh flight grounded for about 12 hours. An anonymous phone call informing the flight control tower that a powerful bomb was planted in the vegetable container of the DC-10 aircraft put the airport authorities instantly on red alert. But a thorough security check proved the threat was but a hoax, officials of the national flag carrier said. The Biman aircraft of Dhaka-Chittagong-Dubai flight with 44 passengers, a four-member crew and four crates of vegetables on board left Dhaka at 7:50am, airport sources said. It landed at the Chittagong airport at 8:34am to take another 227 passengers and three more vegetable crates on board and then depart for Dubai at 9:34am.