At around 8:30 a.m., a pyrotechnic element containing 24 t of solid fuel propellant, loaded in a container, was being transported between two classified facilities when the trailer locked up at the start of a turn. The wheels of its 3 rear axles were pointing to the right: the trailer, which was overloaded was unusable. It was loaded with 54 t of cargo, although the limit was 34 t. The hydraulic steering system switched to safe mode as soon as the rear wheels began to turn.

The operator decided to transfer the cargo to another trailer (the one habitually used). The solution chosen for the operation consisted in dismantling the walls of the container and lifting the pyrotechnic element with the crane and then transferring it to the other trailer. At around 5:30 p.m., it was placed back on the trailer, because the element was not in a horizontal position when the lifting operation began, and there was a risk of it swinging.

The decision was made to raise the container’s floor with its jacks, remove the trailer after realigning its rear wheels, then put the second trailer in place and lower the container by retracting the jacks. The operation was performed in the evening. The incident ended at 11:45 p.m.

This event can be attributed to multiple causes:

• the transporter’s use of an unqualified trailer without the operator’s permission;
• incomplete consignment note (work order issued to the subcontractor);
• no inspection was carried out on the operator’s premises which would have allowed an anomaly to be detected regarding the choice of tractor or trailer;
• no inspection carried out on the tractor and trailer assembly by the transporter;
• there was only one single authorised trailer, but it had not been identified as a specific and unique transport means by the operator (this explains the absence of inspection procedures and instructions for use);
• a lack of specific information regarding the designation of the operator’s departments in charge of inspecting the transport equipment, following changes in the tasks assigned to each department between final rocket’s qualification and assembly campaigns.

The operator bolstered its inspection procedures with regard to the means for transporting internal hazardous materials, defined a procedure for implementing the authorised trailer, and formalised the communication process with the transporter.