What happened
On October 16, 2017, at approximately 12:00, a pilot departed from the Altes Lager airfield in a VIVID FW ultralight aircraft. After performing several local circuits, the pilot departed in a northeasterly direction. At around 13:23, witnesses near the Neuhof district, approximately 7 km west of the airfield, observed the aircraft descending in a spinning flight path. Witnesses reported hearing a loud bang followed by a hissing sound. The aircraft struck the ground with a high longitudinal pitch, resulting in the fatal injury of the pilot and the total destruction of the aircraft.
The investigation
The BFU investigation examined the aircraft's maintenance history, registration status, and the mechanics of the crash. The aircraft, a homebuilt VIVID FW, was operating under French registration. Because it was registered in France, the aircraft was subject to owner self-declarations regarding airworthiness rather than periodic inspections by a certified examiner. The investigation also reviewed the installation of the BRS 5 UL 3 emergency parachute system and the aircraft's weight and balance.
Investigators found that the aircraft's maximum takeoff mass had been increased to 472.5 kg, exceeding the 400 kg limit specified in the German type certificate and the 410 kg limit for the installed parachute system. Furthermore, the investigation focused on the parachute deployment mechanism, noting that the rocket motor had pierced the fuselage and caused thermal damage to the cockpit glazing.
Findings
- The pilot lost control of the aircraft, leading to the fatal impact.
- The improper installation of the emergency parachute system caused the system to fail to deploy the parachute outside of the airframe.
- The rocket motor was misaligned during reinstallation, causing it to snag on the fuselage structure and partially exit the side of the aircraft instead of pulling the parachute out correctly.
- The aircraft was operating at a maximum takeoff mass of 472.5 kg, which exceeded the certified limits for both the airframe and the parachute system.
- While various modifications were noted, including a recent engine change and the use of a non-standard battery mounting, the investigation could not definitively determine if these changes contributed to the initial loss of control.