20011113030059A

(.19) On November 13, 2001, at 0920 central standard time, an aero commander 200D, N28PC, was substantially damaged in cruise flight after experiencing an elevator control anomaly near Houston, Texas. The airplane was registered to three private individuals and operated by the pilot. The commercial pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed and an instrument flight rules (IFR) flight plan was filed for the 14 code of federal regulations part 91 personal flight. The flight originated from the west Houston airport, Houston, Texas, at 0915. According to the pilot, five minutes into the flight, the airplane began to vibrate, accompanied by "stick shaking". Subsequently, the pilot reduced power and executed an emergency landing to the David Wayne Hooks memorial airport located near spring, Texas. Examination of the airplane by the pilot revealed damage to the elevator and horizontal stabilizer. (-23) pilot reported that he departed mineral wells, TX on an IFR flight. Ten minutes later at 4000 ft with autopilot engaged the aircraft started to vibrate. About ten seconds later the aircraft suddenly gained altitude by 3 00 ft and shook violently. The pilot declared an emergency and diverted to dwh. As the speed was reduced from 165 mph to 120 mph the shaking decreased. Inspection of the aircraft revealed the the outboard hinge of the left elevator removed a 1" x 2 1/2" piece of material from the horizontal stabilizer and then separated. Maintenance records revealed that repairs were performed on the left elevator and the autopilot system. (.4) the airplane departed on an IFR flight plan and ten minutes had elapsed when a vibration in the airframe was felt, which gradually intensified. The pilot observed that the horizontal stabilizer was shaking with more intensity than the rest of the airplane. The vibration continued to intensify to the degree that the cockpit instruments were unreadable. The pilot declared an emergency to air traffic control and initiated an emergency descent. He then slowed the airplane to 120 knots and the vibration subsided; however, the vibration was still apparent. Subsequently, the airplane landed, and when the pilot exited the airplane, he observed that the left elevator was hanging 3-4 inches low, at the outboard end. Examination of the airplane b y an FAA inspector revealed that the outboard left elevator hinge had separated from the horizontal stabilizer. A section of the aft spar had separated from the horizontal stabilizer and remained attached to the elevator hinge. Additionally, the left elevator trim tab push rod had separated in two places. Approximately 10 flight hours prior to the accident, several dents were found on the left elevator. The repair station reported that during the repair, rivets on a portion of the elevator were removed, and then replaced while the elevator remained attached the horizontal stabilizer. They added that no abnormal stresses were placed on the elevator hinge attachments during the repairs.