What happened
On August 27, 2019, a Socata MS893A was performing the fourth of five scheduled banner towing flights for a local horse racing event at Kortrijk – Flanders International Airport (EBKT). After departing from runway 24, the pilot released the towing cable and began a leftward turn toward the banner pick-up point. However, the cable had not been fully released and remained attached to the aircraft, trailing a deployed parachute.
Ground personnel observed that the cable was still connected and alerted the pilot to drop it. During this period, the trailing cable moved around the airframe and became entangled with the stabilizer and elevator. This interference caused the aircraft to pitch down uncontrollably, leading to a crash on the right side of the runway where the aircraft flipped over. The pilot sustained 1 fatal injury.
The investigation
The AAIU(Be) examined the aircraft's modification for banner towing, specifically the grappling hook and cable assembly. The investigation revealed that the towing components had been transferred from a different aircraft that had been modified over 30 years prior, and documentation for the forward hook design was missing. Investigators also reviewed the operator's safety management system, the airport's towing procedures, and the communication between the ground crew and the pilot during the incident.
Findings
Several critical factors contributed to the accident:
- The inadequate design of the front hook was a primary factor in the mechanical failure.
- The towing cable was not properly released, leaving the parachute and line attached to the aircraft.
- The trailing cable physically interfered with the aircraft's elevator and stabilizer, causing the loss of control.
- There were flaws in the operator's risk analysis, which failed to account for the possibility of an early release of the aft hook.
- Communication between the ground crew and the pilot lacked standardized phraseology, potentially leading to a misunderstanding of the emergency.
Safety action
Following the investigation, several safety improvements were implemented or recommended:
- The EBKT Airport Manual was updated to prohibit banner towing pick-ups, removing a significant operational hazard.
- A recommendation was made to the Belgian CAA to review the design of the front hook on Belgian-registered aircraft using similar towing equipment.
- The operator was advised to overhaul its safety management system to ensure risk analyses are robust and procedures are strictly followed.
- The Belgian CAA was encouraged to clarify technical specifications regarding the design and maintenance of banner towing cables.