An analysis of historic passenger numbers prepared by FRIST (Mike Peaker) a few years ago is helpful when considering the impact of the proposed new service. Given the general strength in the tourism market there is no obvious reason why the re-introduction of the helicopter service should not see a return to air passenger numbers of ~170,000 per year (40,000 via Tresco). This is a step change from current levels (~ 95,000), a lifeline for IOS Airport and a major boost for the local economy.
Fears that some islanders have expressed that the new service will only benefit Tresco visitors are unfounded. It will be economically essential for new service to serve both St Mary's and Tresco like the previous BIH service.
Passenger stats here.