What happened
On 9 May 1998, a BAe ATP, registration G-MANP, was undergoing a routine pushback from Stand 9 at Jersey Airport. The aircraft, operated as a public transport flight, was being maneuvered by a ground tug. During the procedure, the No 2 engine had been started prior to pushback, followed by the No 1 engine as the aircraft began to turn onto the taxiway.
As the aircraft was being straightened on the taxiway centerline, the towbar failed. This caused the aircraft to surge forward approximately twenty feet, resulting in the right-hand propeller striking the cab of the tug. The impact caused significant damage to the engine nacelle, propeller blades, and the aircraft fuselage, while the tug's cab was also damaged and its door was ripped off.
Following the collision, smoke was observed in the flight deck. The crew initiated an immediate evacuation of the 46 passengers and 4 crew members. Despite the presence of elderly and infirm passengers, the evacuation was completed in an orderly manner without any fatalities or serious injuries.
The investigation
The investigation examined the flight data recorder (FDR) and the physical condition of the aircraft, the tug, and the towbar. Analysis of the FDR revealed that both engines were operating at significantly higher torque levels than normal during the starts on the day of the accident. Specifically, the No 2 engine was at 15% torque and the No 1 engine was at 10%, whereas the standard setting is typically between 7% and 8%.
The towbar, which had been modified for use with the ATP, was found to have a failed weld at the towing eye. This failure occurred due to a low-cycle, high-stress fatigue mechanism. The investigation also noted that the tug was in a poor state of maintenance, though this was not considered the direct cause of the accident.
Findings
- The excessive engine torque on both engines was the initiating event of the accident.
- The crew did not notice the higher than normal torque levels during the engine starts.
- The towbar's towing eye failed due to fatigue, following a series of stress cycles.
- The aircraft's forward momentum caused the tug to jack-knife, leading to the propeller strike.
- The tug's front wheels were lifted by the force of the aircraft, reducing steering capability and contributing to the instability.