 Complete the following phrase:  In 19741975, he worked for Hawker Siddeley as a senior vice president supporting HS146 activities in the United States. In 1977, he joined the United States House of Representatives Committee on Science and Technology where he served, until his retirement in 1993, as a technical adviser on all aspects of civil aviation research and development and became one of the nations leading advocates for a reinvigorated research airplane program. In 1986, this House Committee tasked Crossfield to be a member of the task group assigned to investigate the 