In October 1995, Doxiadis Associates signed a contract with HOCHTIEF AG, to provide a five-member architectural design team in HOCHTIEF's headquarters in Essen. The Doxiadis Associates team in Essen worked for a six month period jointly with the HOCHTIEF team in developing the second design phase of the airport. Eventually the German-Greek team was transferred to Athens for the execution of the project. Thereafter, HOCHTIEF AG assigned Doxiadis Associates with the preparation of the 60% for the design services for the Central Terminal Building of the new Athens Airport at Spata. The assignment included the preparation of the final architectural design and construction drawings. Services were offered - in special offices at the site of the new airport - from a 22 D.A. members, of which 18 were architects. Design works were prepared exclusively by computer. A quality assurance system (ISO 9001) was used throughout the project.