What happened
On 21 April 2022, a Cessna T210N Centurion, registration ZS-TCG, departed from the Die Eike Private Farm Airstrip near Standerton, Mpumalanga, for a scheduled maintenance flight to Wonderboom Aerodrome. During the initial climb, the pilot retracted the landing gear and flaps as per standard procedure. However, after leveling off at approximately 700 feet, the pilot attempted to reduce manifold pressure and engine RPM. This adjustment triggered a sudden and significant loss of engine power.
Unable to maintain altitude, the pilot attempted to return to the departure airstrip but found the aircraft losing height too rapidly. Identifying a suitable patch of ground on a gravel road between two irrigated fields, the pilot executed a forced landing. During the landing roll, the aircraft's left main gear struck a rock, causing the gear to break off. The resulting impact caused the left wing and aileron to strike the ground, leading the aircraft to veer off the road and into a cultivated area. The nose gear subsequently collapsed, and the propeller struck the ground, resulting in substantial damage to the aircraft. The pilot escaped the incident without injury.
The investigation
SACAA AIID examined the engine and the aircraft's operational history. Post-accident inspections of the engine revealed no immediate mechanical abnormalities, and the engine functioned normally during subsequent test runs. However, investigators noted that when the fuel mixture control was excessively leaned during testing, the engine experienced power loss, mirroring the conditions of the accident.
Technical analysis highlighted the complexities of the aircraft's turbocharging system. Unlike the pilot's previous experience with the normally aspirated Cessna C182, the Cessna T210N utilizes a waste gate to manage manifold pressure. The investigation noted that when the waste gate is fully closed, any fluctuations in turbine speed directly impact engine performance. The pilot had relatively limited experience with this specific type, with only 14.7 hours logged on the Cessna T210N.
Findings
- The engine experienced a sudden drop in power following a reduction in manifold pressure and RPM.
- The pilot's previous flight experience was primarily on normally aspirated aircraft, which lack the specific turbocharging characteristics of the Cessna T210N.
- The engine power loss was caused by an undetermined factor during the transition to cruise power settings.
- The forced landing resulted in significant structural damage to the landing gear, wing, and propeller due to contact with terrain obstacles.