During the first take-off for top dressing operations, the aircraft commenced to swing to the left. The pilot applied opposite rudder and braking but was unable to control the swing. The side loads imposed on the right hand gear caused it to fail at its attachment to the stub wing, and fold up. The left hand oleo strut piston had separated from its cylinder, which then failed at its attachment, and fell from the aircraft. The gear then started to fold back, bringing the piston into contact with the tyre, which gave a braking affect and caused the aircraft to swing. A Transavia Service Bulletin and an Airworthiness Directive require a mandatory inspection to be carried out on all oleo struts of this type after each 100 hours time in service, in order to prevent a failure of this nature from occurring. The aircraft log books could not be located, and it could not be established whether the required inspections had been carried out.