History of Flight
On 25 January 2007, a Bell UH-1H/B205 helicopter, registration ZU-UHI, was dispatched from Tulbagh Aerodrome to assist in a fire-fighting operation at the farm Orchards near de Doorns. After completing four successful water drops, the pilot returned to a farm dam to uplift a fifth load of water. During transition to hover, he heard an unusual noise from the rear of the helicopter. The noise intensified, and the helicopter began to vibrate. Shortly after, the pilot noticed smoke in his peripheral vision, appearing to originate from the rear. The helicopter then yawed left, the low rotor RPM warning light illuminated, and the audio warning sounded. The pilot was unable to maintain altitude and executed an emergency ditching in the dam. The pilot was not injured and swam to shore unassisted.
Injuries and Damage
The pilot sustained no injuries. The helicopter’s structure suffered only minor damage, though all onboard equipment was water-logged and required major repair or replacement.
Engine Investigation
The engine, a Honeywell-Lycoming T53-L-13B (serial number 30172-B), was removed from the recovered helicopter and subjected to a teardown inspection. The inspection revealed an internal bearing failure resulting from the failure of a carbon seal.
Probable Cause
The engine failed as a result of an internal bearing seizure/failure, causing the helicopter to lose altitude and impact with the water.