Birmingham council principal planning officer Ron Moss said: "Based on comments made by the Civil Aviation Authority it has been decided that on safety grounds the height is not acceptable. It will have to be reduced."
Architect Ian Simpson said: "The building is in the city core, which is not critical as a flightpath. Normally you would try to argue the point, but after 11 September they are less likely to accept a relaxation of the regulations."
The mixed-use tower, developed by Beetham Birmingham, was to have contained 213 residential units, office space and retail space. In the original plan it was to have had 44 storeys; it is not known how many it will now contain, as the updated design has not been submitted.
Simpson said: "We are going to pursue the project, but to satisfy the conditions for planning we will have to reduce it. It might have to go down to 150 m."