A Learjet 35A aircraft with registration ZS-SFV departed Cape Town International Airport (FACT) for Lanseria International Airport (FALA) with two pilots and three passengers on-board. The crew reported that during the cruise, descent and landing phases to FALA, a sequence of defects occurred which interrupted their pre-landing checklist procedures. As a result, the landing gear lever was not selected down. Therefore, the aircraft was landed with landing gears up; it skidded on its belly and came to rest approximately 2 kilometers from the threshold of runway 25. All occupants were not injured during the accident sequence. The aircraft was substantially damaged. Probable Cause: The crew forgot to lower the landing gear and the aircraft landed with the landing gears up (retracted). The aircraft had multiple instrument failures in-flight which increased the pilots’ workload in the cockpit. This resulted in the pilots omitting to lower the landing gear and the aircraft landed with the landing gears up. Contributory Factors: – The crew was distracted by multiple recurring defects. – The crew did not consult the pre-landing checklist. – Unserviceable landing gear warning horn. – Poor maintenance.