The lifting schedule, already delayed from 17 August, has now been put back a further four weeks.
The £30m wheel was not erected because sockets holding supporting cables failed during testing on the day of the lift. The sockets are now being redesigned.
Tim Renwick, a director of the wheel’s construction manager and project manager Mace, could not confirm that the project would be ready for its timetabled opening on 31 December.
“We are reassessing the programme, and although the wheel lift is critical, it has to be done safely,” said Renwick.
He said the 1600 tonnes of steel would not be lifted until it was absolutely certain that it would work.
British Airways spokesman Jamie Bowden said: “We are not sure what will happen to the rest of the schedule, but a delay of three to four weeks is likely to have an effect. We believe the completion date is still possible, but it is too early to say.”
The problem was caused by a design fault on the socket that connected the 30 temporary cables from the spindle of the crane to the rim of the wheel. The temporary cables were used as added support to the main cables connecting the wheel’s hub to the spindle on the A-frame crane when it lifted the wheel into a vertical position.
Project sources explained that, during the last test before the lift, one temporary cable sprang loose from its socket, putting extra strain on surrounding cables, which caused another four to spring loose. The operation was halted immediately.
Mace and steelwork contractor Hollandia will now replace all 30 temporary cables and redesign the connecting sockets to keep the cables in place. They will then test the whole procedure again.
French ski lift manufacturer Poma is currently building more of the wheel’s people-carrying capsules off site, in order to make up some time.
Other work has been rescheduled to try to minimise the impact of the failure. The electrical works on the boarding platform to the wheel will take place before the lift, instead of afterwards.
Renwick said he was not anticipating any contractual claims from specialist contractors involved in the project.
At this stage, British Airways could not say how much the delay will cost the project. Both British Airways and Mace say there is no blame to be apportioned to any party.
British Airways spokesman Bowden said: “There is no witch-hunt. One of the things we made clear was that it was the first time [for such a lift] and it would have teething problems.”