What happened
On 22 November 2009, a Cessna 210N, registration ZS-KUT, was conducting a private cross-country flight from Stellenbosch Aerodrome to Saldanha-Vredenburg Aerodrome and back. Shortly after departure from Stellenbosch, the pilot successfully retracted the landing gear as part of the normal takeoff sequence. However, while flying over Saldanha-Vredenburg with the intention of performing a touch-and-go, the pilot attempted to extend the gear and heard an unusual noise from the hydraulic pump. An amber indicator light illuminated, signaling that the gear was only partially extended.
In an attempt to rectify the situation, the pilot cycled the landing gear and utilized the emergency manual hand pump, but the gear remained stuck. The pilot then identified a lack of hydraulic fluid in the reservoir and replenished the system using onboard spares. Despite these efforts and a visual confirmation from another aircraft that only the nose gear appeared to be down, the main gear failed to lock. The pilot subsequently declared an emergency and diverted to Cape Town International Aer to perform a forced landing on runway 16. During the landing, the aircraft's main wheels remained retracted, causing the aircraft to skid and veer to the right. The impact resulted in damage to the propeller, the left wing, and the lower fuselage.
The investigation
SACAA AIID investigators examined the aircraft at a maintenance facility to identify the source of the malfunction. The aircraft was placed on jacks, and the landing gear was cycled using both the electrical control handle and the mechanical emergency system. During these tests, the landing gear retracted and extended without issue. Multiple cycles were performed, all of which were successful.
Investigators also reviewed the maintenance history of the hydraulic power pack, which had been overhauled in July 2008. The records indicated that the overhaul included the replacement of all seals and pressure adjustments, and subsequent bench testing had shown no problems. No evidence of a hydraulic leak was found during the post-accident inspection of the airframe.
Findings
- The pilot was properly rated and held a valid medical certificate.
- The aircraft had been maintained in accordance with all regulatory requirements, including the most recent periodic inspection.
- The main landing gear failed to extend during the flight.
- The pilot attempted to troubleshoot the issue by replenishing hydraulic fluid and using the emergency pump.
- Weather conditions at the time of the accident were clear and did not contribute to the event.