 This obviously led to problems in collaboration between project teams during both the BD and DD phases.Because of the waterfall method of Go/No Go decisions at the end of each phase, the technical crew would have to make a formal Change request in order to make corrections in the detailed sections of the Basic Design.Such changes were often confusing for the customer, because these originated from the project team rather than directly from the customer requirements, "even after a change freeze was put in place".