The short runways at Polebrook were found to be unsatisfactory for the operation of the heavy-loaded, four-engine B-17. In 1942 the airfield was improved to Class A airfield standards. The main runway was extended to 1,950 yards and the secondary runways to 1,400 yards each. In addition, additional hardstands were constructed, increasing the total number from 30 to 50. This enlargement resulted in the unusual situation that the ammunition storage area was inside the extended perimeter track. The living and communal sites were dispersed in woodlands north of the airfield. They provided accommodations to about 2,000 personnel.