Avoiding Groupthink with the Rail Project

Your tight-knit engineering team has been working on the community's maglev rail project for three years. The completion deadline is in two weeks. While the project has been plagued with challenges such as inferior equipment, bad weather and cost overruns, it looks as if it may make the projected target date (planned to coincide with the new mayor's inaugural address) for the unveiling. Your team has just overcome a major hurdle of the project and has gone out for a well-deserved celebration.

Before leaving to join your team, you discover that one of the magnetic devices is not working properly - a problem that will delay the project another 6 -12 months.

How would you approach the situation and avoid the problem of Groupthink?