What happened
On August 30, 2004, at 18:40 UTC, a Cessna C 414, registration EC-FTA, was being towed to a hangar at Ostrava-Mošnov Airport (LKMT) for finishing works following maintenance and repainting. The aircraft was being moved along taxiway F by a Zetor 7211 tractor using a Tronair tow bar.
During the towing operation, the tractor was traveling at an estimated speed of 20 km/h. This speed caused the aircraft to undergo lateral oscillations with increasing amplitude. The resulting physical stresses caused the nose gear to break off, leading to a violent impact of the aircraft's tail and then its nose against the concrete taxiway surface. The aircraft eventually came to a stop approximately 150 meters past the junction of taxiway F and taxiway C. There were no injuries to the tractor driver, the passenger in the tractor, or any other persons.
The investigation
The ÚZPLN investigation established several critical technical and procedural discrepancies during the towing process. The investigation found that the tow bar assembly was mismatched; the towing eye on the aircraft had a diameter of 100 mm, while the pin on the towing equipment was only 35 mm, creating significant play. Furthermore, the towing equipment used was specifically designed for larger aircraft types, such as Learjet and Citation I/II, rather than the Cessna 414.
Investigators also noted that the tractor's tires were unevenly worn, contributing to instability during movement. Additionally, there was no means of communication between the tractor driver and the aircraft, nor was the towing vehicle in radio contact with the Ostrava airport air traffic control service. The investigation also noted that the Cessna 414 service manual recommends having two assistants walking at the wingtips during towing, and suggests a much lower speed—approximately 5 km/h—to ensure control.
Findings
- The primary cause of the accident was towing the aircraft at an excessive speed.
- The use of inappropriate towing equipment with excessive play in the connection.
- Inadequate attention from the person responsible for the towing operation regarding the aircraft's lateral movement.
- The poor technical condition of the tractor's tires, which caused vehicle instability.
- Lack of communication between the towing vehicle and the aircraft or airport authorities.