On May 30, 1994, at 1842 central daylight time (CDT), a Hawker- Siddeley DH-125-3A, N900CD, registered to D.B. Aviation/Ditka Corporation, of Waukegan, Illinois, and piloted by an airline transport and commercially rated crew, was substantially damaged during a hard landing on runway 23 (6,000'X 150' dry concrete) at the Waukegan Regional Airport, Waukegan, Illinois. Visual meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 positioning flight was not operating on a flight plan. The pilots reported no injuries. The flight departed Wheeling, Illinois, at 1835 CDT. According to the captain's written statement attached to NTSB Form, 6120.1/2, the copilot was flying the approach which was normal until about 200 feet above the ground. He stated the sink rate then increased and he called out, "descending below vasi." Elevator back pressure was increased with little or no effect. Trim to increase pitch-up was also applied. The callout "pull up" was then made. At this time the control yoke was pulled back with great force by both pilots. A hard landing followed. During the flight crew's post flight inspection of the airplane a trip manifest container was found wedged between the copilot's seat and control yoke column. The container was "...severely bent", according to the captain's written statement. Both pilots were asked where the trip manifest container is normally stored. They responded that there is no storage space specifically designated in the cockpit for the container. According to the captain, the container is usually stored against the cockpit's right sidewall. Both pilots said the container has always been stored in that position since they have been with the company. They said the company required that the container be kept in the cockpit. The copilot stated the container's size was 9" X 12" X 1".