Incident Details
A jet aircraft struck a tug during pushback after the ground crew disconnected the tow bar without receiving an acknowledgment from the flight crew. The ground crew were not using headsets while performing the pushback. They did not follow company procedures: they disconnected the tow bar without receiving an acknowledgment from the flight crew.
Although the ground crew utilized hand signal procedures twice, they were unable to see the captain's response due to poor lighting conditions. Meanwhile, the flight crew were starting the engines and did not see nor acknowledge the parking brake signal. Consequently, they were not aware that the ground crew had disconnected the tow bar. Moments later, the jet rolled forward and struck the tug.
Contributing Factors
The incident involved a breakdown in communication between ground and flight crews. The ground crew's failure to use headsets and to follow procedures for obtaining acknowledgment contributed to the misunderstanding. Poor lighting further hindered visual hand signals. The flight crew's focus on engine start procedures prevented them from seeing the parking brake signal, leaving them unaware that the tow bar had been disconnected.