What happened
On the evening of November 8, 1991, a Cessna T 310 R departed Mannheim-Neuostheim for a private instrument flight rules (IFR) trip to Essen-Mülheim. The aircraft was carrying the pilot and one passenger. During the climb, the aircraft encountered heavy precipitation and intense icing conditions as it passed through the freezing level.
While attempting to climb to FL 140 to clear the cloud tops and escape the icing zone, the aircraft's airspeed dropped significantly. At approximately 19:19 UTC, the pilot transmitted a final radio message stating, "troubles sir, descending to FL 80," before the aircraft entered an uncontrolled descent. Radar data indicated a spiral dive with sink rates exceeding 10,000 feet per minute. The aircraft struck the roof of a residential building in downtown Darmstadt at a steep angle. The impact and subsequent fuel fire destroyed the aircraft and several residential units. The crash resulted in four fatalities: both occupants of the aircraft and two residents of the building. One resident sustained serious injuries.
The investigation
The investigation examined the aircraft's performance, meteorological conditions, and the pilot's actions. Investigators analyzed radar tracks, radio communications, and even recovered audio from a nearby school's video recording of a theater performance, which confirmed that both engines were operating at equal power and approximately 2,700 RPM at the time of the crash. The investigation also reviewed the pilot's flight experience and the aircraft's maintenance history, finding the pilot fully rated for IFR flight and the aircraft properly maintained and equipped for flight in icing conditions.
Findings
- The aircraft encountered heavy, intensifying ice accumulation while climbing through precipitation.
- The required minimum airspeed for flight in icing conditions was undershot during the climb.
- The pilot was unable to regain control of the aircraft after it stalled/pitched up while flying in night instrument meteorological conditions (IMC).
- The engines were functioning normally, and the aircraft's weight and balance were within limits.