History of Flight
The aircraft, a Boeing 737-300 registered ZS-SMG, operated by SAFAIR Operations (Pty) Ltd, departed OR Tambo International Airport at 0220Z on 11 February 2010 for a routine cargo haul flight to Cape Town International Airport. Upon arrival at Cape Town, ground crew informed the pilot that the number one main outboard wheel assembly was missing. The pilot reported no adverse vibration during take-off or landing. Inspection revealed damage to the inner left aft flap.
Injuries and Damage
Neither of the two occupants (one pilot, one co-pilot) was injured. The aircraft sustained minor damage on the bottom of the left flap. A runway inspection at Cape Town failed to locate the missing wheel; it was later found at OR Tambo by grass cutters.
Probable Cause
The outer main wheel bearing failed during take-off, causing the wheel assembly to depart from the axle. Disintegration of the bearing produced shards that pierced the left flap. A contributing factor was that an incorrect bearing had been fitted to the wheel assembly during maintenance on 30 December 2009.