What happened
On October 16, 2002, a Fairchild Dornier DO 228-200 operating a scheduled flight from Leipzig to Dortmund experienced severe oscillations around the vertical axis while cruising at FL 80. The aircraft was near Kassel when the crew, experiencing difficult-to-control vibrations at an indicated airspeed of approximately 175 kt, decided to divert for an emergency landing at Paderborn-Lippstadt.
During the emergency, the crew notified Bremen Radar of a rudder failure. To mitigate the oscillations, the crew reduced the airspeed to 120 kt, which stabilized the aircraft. The crew followed instructions for a visual approach to runway 2/4 and landed safely at 18:40 local time. There were no injuries to the occupants, though the aircraft sustained heavy damage.
The investigation
The BFU investigation focused on the structural integrity of the rudder. Upon inspection, investigators found that the fabric covering on both sides of the rudder had almost entirely detached from the metal structure, with only a small fragment remaining. No adhesive residue was found on the metal surfaces.
The investigation revealed that the rudder had undergone a re-covering procedure on October 13, 2002, just three days prior to the accident. This work was performed by a mechanic from the aircraft operator's maintenance facility. The investigation examined the procedures used, the materials applied, and the documentation regarding this maintenance task.
Findings
- The maintenance was performed using the German Aero Club (DAeC) manual rather than the manufacturer's (Dornier) Structural Repair Manual.
- The technician used "SUPER BOND" adhesive instead of the manufacturer-specified contact adhesives.
- The investigation found that the improper application of the fabric covering was the primary cause of the failure.
- There was no formal report, inspection protocol, or maintenance log entry documenting the re-covering process or the required adhesion tests.
- The maintenance lacked the necessary diligence, specifically regarding the surface preparation and the reactivation of contact adhesives required by the manufacturer's instructions.