The latest suspension of Lantau's cable car service on Wednesday came after a fourth technical fault in two months, but according to the operator the faults were all in different parts of the system.
After hundreds were trapped in cable car gondolas for around 90 minutes due to a fault, preliminary checks have shown a 42cm bearing on the haul rope pulley wheel at the Airport Island Angle Station to be slightly worn.
'We found no safety problem with the system. It is the reliability of service that is in question,' said Frank Chan Fan, director of electrical and mechanical services, adding that the system's six other identical bearings would be checked during a 10-day suspension.
He said the cold weather was unlikely to have caused the fault, since the cable car should be capable of withstanding Hong Kong's humidity and temperatures. Government-appointed experts reviewing the cable car's design after one fell to the ground in 2007 found it complied with international standards.
Professor Lo Kwok-keung, of Polytechnic University's department of mechanical engineering, said damage to the bearing was so minor it might not have been noticed during regular maintenance checks.
He said the part needed to be well lubricated, but if that had been done then the bearing might have been old and and ready for replacement. Or it might not have been of sufficient quality in the first place.