What happened
On the evening of 12 January 1999, a BAe 146, registration G-TNTL, was parked at Stand 67 on the South Apron of Dublin Airport. The aircraft, which was operating a cargo flight from Cork, had been repositioned at the stand to accommodate additional cargo arriving from Shannon before its scheduled departure to Liverpool.
During the evening, a tow truck operated by a ground handling agency was maneuvering through the South apron. While turning near Stand 66, one of the two cargo dollies being towed by the vehicle became detached. The runaway dolly crossed the designated roadway, narrowly avoiding another aircraft, and traveled approximately 90 metres before striking the stationary BAe 146. The impact caused damage to the left-hand undercarriage door, the squat switch, and the lower portion of the undercarriage body housing. The pilot, present in the cockpit at the time, felt the impact and subsequently declared the aircraft unserviceable.
The investigation
The investigation focused on the mechanical state of the towing equipment and the circumstances of the detachment. While the specific ownership of the dollies could not be confirmed, investigators noted that the equipment did not feature the spring-loaded locking devices found on DHL-owned dollies.
Examination of photographs taken by airport police revealed that the locking mechanism on the lead dolly was faulty. Specifically, the vertical locking bolt was bent, preventing it from fully seating into the securing lug. This misalignment allowed the bolt to dislodge during transit, particularly as the vehicle passed over a gully at the entrance to the South stand. Subsequent inspections of other equipment at the airport revealed that at least one other dolly possessed a similar defect in its connecting mechanism.
Findings
- The primary cause of the incident was a defective locking bolt on the first dolly, which was too bent to lock securely.
- The mechanical failure allowed the bolt to pop upward during transit, resulting in the uncontrolled release of the second dolly.
- The impact was triggered when the tow vehicle traversed a gully, providing the physical disturbance necessary to dislodge the improperly secured bolt.