Incident Summary
According to the pilot, while descending from 3,500 feet at an indicated airspeed of 180 knots, the airplane began to vibrate. The pilot reduced power and raised the nose to slow the airplane. The descent was continued at 120 miles per hour. The airplane landed without any further incident.
Descent and Landing
The vibration occurred during the descent phase of flight. The pilot's response included reducing engine power and adjusting the aircraft's pitch attitude. The descent speed was subsequently maintained at 120 MPH. No other abnormalities were reported during the remainder of the flight, and the landing was uneventful.
Post-Landing Inspection
During the post-landing inspection of the airplane, the pilot discovered that the empennage aft of the rear bulkhead had substantial wrinkling in the area near the horizontal stabilizers. The wrinkling was noted as a structural anomaly. No other damage was reported. The specific cause of the vibration and wrinkling was not determined in the provided information.