Shortly after take-off from Katherine, Australia, the left main landing gear of the Beech 200 aircraft did not retract. The flight continued to Darwin with the landing gear extended. During approach to Darwin airport the pilot advised air traffic control that he could not obtain a green ‘down and locked’ indication for the left main landing gear, and declared an emergency prior to landing. During touchdown, the left main landing gear collapsed and the aircraft slewed off the runway. Both occupants evacuated the aircraft with no injuries. The aircraft operator’s maintenance organisation examined the aircraft and found that the left main landing gear drive shaft had severed as a result of fretting against a bleed air duct clamp tail. The bleed air duct clamp (jubilee clamp) had been fitted to the aircraft during an aircraft refurbishment program in September 2003. The jubilee clamp tail had been fastened in close proximity to the landing gear drive shaft. Subsequently, the jubilee clamp tail had come into close contact with the drive shaft, leading to severe wear of the drive shaft section and eventual failure.