On 25th November 2011 the steel roof trusses for the extension to the Air-Traffic Control Centre at Munich Airport were lifted into place. The seven trusses span over the flight controllers future operations room to produce a 1700m² column free space. The trusses were 40m long and weigh approx. 15tonnes. They were each delivered in two sections, bolted together on site and lifted by two mobile cranes to form the 10m high roof. The trusses will be connected together by a concrete slab 18cm thick, made of pre-cast elements with an in-situ topping. Until the concrete has hardened and the composite action of the steel trusses with the concrete flange has been attained, the construction will be supported by temporary columns.