College of Science and Technology. He initiated construction of the laboratory for aerodynamics and construction research. In 1951, upon the death of the Farnborough director, Hall was appointed director of the RAE with the understanding that after five years he would return to Imperial College.
Hall’s Comet investigation became the model for major aviation inquiries. In May 1952 the first passenger-service Comet took off from Heathrow, establishing Britain as a leader in the aviation industry. The Comet 1 was a symbol of confidence and promised financial success for Britain’s aviation industry. However, after two years in service, three Comets failed in flight, causing panic in the industry.
All Comets were grounded. The government sought Hall’s advice and answers for the failures, for which there appeared no obvious explanation. RAE teams were asked to conduct an independent investigation of all possible causes. Hall thought that some of the crucial stress calculations could not be answered by mathematical theory alone. He organized and oversaw the building of the “whole pressurized aircraft” test rig at Farnborough. These labs created an environment in which the stresses of repeated flight cycles could be tested on the aircraft. The evidence revealed that failure of the aircraft’s pressurized cabin was at fault. The conventional testing that had been used until this time proved to be inadequate in determining the “fatigue life” of aluminum alloys under repeated stress.
When his Farnborough agreement came to an end in 1955, Hall accepted a position with the Hawker Siddeley Group as technical director of Bristol Siddeley Engines. Four years later he was appointed managing director of the newly formed Bristol Siddeley Engines, Ltd. In 1967 he was named chairman and managing director of the Hawker Siddeley Group. By the mid-1970s the Hawker Siddeley Group employed about 85,000 people, and had expanded its portfolio to include electrical and civil engineering. Hall believed in private enterprise and was opposed to the government’s nationalization proposals. He left the aircraft industry in 1977 when the government nationalized the industry.