Two hundred passengers on the Lantau cable car were stranded in mid-air for 50 minutes yesterday when a misplaced conveyor belt halted operations - the longest such halt since the service reopened on December 31. The latest hitch was caused by a technical error that occurred for the first time, a spokesman said. Engineers insisted the incident did not endanger anyone. The incident happened at 3.40pm when a belt that pulls the cable into the terminal tower at Ngong Ping slipped out of position. The system automatically shut down and service resumed at 4.30pm. Previous delays during the period after the system was brought back into service in December were no longer than eight minutes. Broadcasts inside the gondola informed passengers about the problem three minutes after the system halted, although some passengers complained they were not informed. Ngong Ping 360 cable car officials were investigating last night, but a spokesman said it was a one-off incident and normal service would resume today. The former president of the Hong Kong Institute of Engineers, Edmund Leung Kwong-ho, said the error was an operational one without safety implications. 'Even if the belt slipped away from the pulley, the gondola would not fall, because it is not the belt but a rail track inside the terminal that supports the weight of the gondola,' Mr Leung said. He said a set of conveyor belts at the terminal building replaced the cable system that propelled the gondolas when they arrived at the terminal. Those conveyor belts were propelled by a set of tyres. If a tyre shrank because of air leakage or any other reason, it was possible for a belt to move out of position. Mechanical engineer Lo Kok-keung agreed, adding that the MTR Corp had been quick to spot and fix the problem. The last inspection was conducted on February 6 and the next one is scheduled on April 8 and 9.