Summary of an aircraft accident: Accident report by the Federal Bureau of Aircraft Accident Investigation
Introduction
On 23 March 2022, a serious aviation accident involving a Reims Aviation Cessna F 172N occurred at Bonn-Hangelar airfield. The pilot and a technician were seriously injured in this accident, and the aircraft and surrounding buildings and areas suffered considerable damage. The accident report by the Federal Bureau of Aircraft Accident Investigation (BFU) sheds light on the details and causes of this incident.
Course of the accident
On the day of the accident, the 84-year-old pilot and a technician from a maintenance organisation met at Bonn-Hangelar airfield to carry out a test flight after completing maintenance work on the Cessna. The take-off took place on runway 11 at 12:41 p.m. Shortly after take-off, the aircraft did not gain sufficient height, brushed against trees in the take-off area and touched down on a field. It then crossed a railway embankment and collided with a garden shed, resulting in a rollover and an inverted position of the aircraft.
Pilot and technician details
The pilot had a comprehensive flying qualification with a private pilot's licence (PPL(A)), which had been valid since 1974, as well as various ratings for different types of aircraft and night flights. His flying experience comprised around 7194 flying hours and 26,781 take-offs and landings. The technician held an aircraft maintenance licence with various ratings and had specialised in the Cessna 172 type since January 2021.
Aircraft details
The Cessna F 172N in question, built in 1979, was a single-engine shoulder-wing aircraft with fixed landing gear and was owned by a flight school. The aircraft had a total operating time of 15,352 hours. During the last maintenance, parts of the control system, including the Y-yoke, were replaced. A test flight was to confirm the release after the maintenance work.
Cause of the accident and investigation results
The investigation revealed that the elevator trim was installed incorrectly, causing the trim tab to deflect in the opposite direction to the movement of the trim wheel. This fault was not recognised during maintenance, although double checks were carried out. The pilot carried out a pre-flight check but did not check the function of the trim tab as this item was not on the checklist.
After take-off, the elevator did not respond as expected. The pilot tried to compensate for the control pressure by adjusting the trim, but this led to an uncontrolled descent. Instead of aborting the take-off immediately, the pilot tried to rectify the problem by making further control movements, which ultimately led to a collision with the trees and the garden shed.
Safety analyses and recommendations
The investigation emphasises the need for a thorough check of all control and operating elements, especially after extensive maintenance work. The incident also emphasises the importance of mental preparation for possible emergencies and correct decision-making under time pressure.
The maintenance team must be aware of the correct installation and operation of all components, especially when it comes to safety-critical systems such as the trim. Better communication and training could help to avoid such errors in the future.
Conclusions
The aircraft accident at Bonn-Hangelar airfield was caused by a combination of a technical malfunction and an inadequate reaction by the pilot. The incorrectly installed trim and the delayed initiation of the aborted take-off contributed significantly to the accident. The BFU emphasises the importance of „good airmanship“ and careful preparation and execution of maintenance work and pre-flight checks in order to ensure aviation safety.
Source references:
Federal Bureau of Aircraft Accident Investigation
