What happened
On August 4, 2017, a Focke-Wulf Fw 44J "Stieglitz" departed from the Chemnitz/Jahnsdorf airfield for a training flight. Shortly after takeoff, the two pilots on board realized that the elevator controls were non-responsive. In an attempt to manage the loss of control, the crew reduced engine power. The aircraft entered a nose-down pitch attitude and struck the ground within the airfield boundaries. The aircraft came to a halt approximately 30 meters from the point of impact. The accident resulted in two minor injuries and significant damage to the aircraft, as well as damage to airfield lighting equipment.
The investigation
The BFU investigation focused on the mechanical failure of the elevator control system. Physical examination of the aircraft revealed that the clevis pin on the rear control rod had completely detached from the control linkage. The investigation also scrutinized the maintenance history of the aircraft, noting that it had undergone an overhaul in Lithuania between 2015 and 2016. The BFU found discrepancies in maintenance documentation, including inconsistent work reports and a lack of proper release-to-service certificates for certain components, such as the propeller and radio. Furthermore, the investigation examined the process by which the German Federal Aviation Office (LBA) issued the flight permit, noting that the permit was granted based on a declaration of safety without a physical inspection of the aircraft by the certifying official.
Findings
- The primary cause of the accident was the separation of the elevator control linkage due to the lack of a positive mechanical locking mechanism (such as a split pin or safety wire) on the clevis pin.
- A lack of clear maintenance documentation regarding the required method for securing the clevis pin contributed to the failure.
- Inadequate organization of the aircraft's maintenance records and oversight of the maintenance process.
- A lack of specific requirements or standards for the issuance of safety declarations during the flight permit process under § 12 LuftVZO.