Charles Stanley has downgraded its rating for aviation support and aftermarket services firm BBA Aviation from buy to add, saying that while the long-term growth drivers are still intact, there are some headwinds in the near-term.On Friday, the group reported a full-year pre-tax profit of $170.2m, in line with the broker's expectations, as it "continued to recover from the market trough experience in FY2009"."The long term drivers for the group remain positive, with Business and General Aviations hours flown forecast to increase 6.6% per annum between 2010 -2020. This coupled with the organic and consolidation opportunities in the fixed-based operator space as well as further license opportunities in Legacy offers significant scope for earnings growth in the medium term," the broker said.However, Charles Stanley highlights the minimal growth expected in flying hours in 2012 after broadly static second half activity in 2011. As such, the broker expects flat profits and negative earnings per share growth (due to the higher number of shares in issues following the placing) this year.The 230p target price is maintained.BC