Boeing 747-430 was being prepared at Frankfurt International Airport's Gate A23 for a scheduled flight, LH760, to Delhi, India. Some repairs were carried out on
... the hydraulics of the left hand body gear while parked at the gate. During a test sequence the nose landing gear's ground lock pin fell out.
This caused the nose landing gear to retract. The nose fell onto a push-back truck.
The reason for the retraction of the nose gear was a malfunction of the lever mechanism within the safety bar in conjunction with the Ground Lock Pin. This left the GLP in the inserted position in an unlocked state.
