What happened
On 06 February 2016, a Cessna S550, registration ZS-CAR, was preparing for a commercial aerial work mission departing from Lanseria International Airport (FALA). The aircraft was operated by the SACAA Flight Inspection Unit and was carrying a crew of three.
During the takeoff roll on Runway 07, the aircraft's cabin pressure began to drop rapidly at a rate of 6000 ft/min. Recognizing the loss of cabin pressure, the pilot in command decided to execute a rejected take-off (RTO). The heavy application of brakes required to bring the aircraft to a halt generated significant heat, which subsequently caused the aircraft tyres to deflate. There were no injuries to the crew, and the aircraft was subsequently recovered to the operator's facility for repairs.
The investigation
SACAA AIID investigators confirmed that the crew members were properly licensed, medically fit, and familiar with the aircraft's performance. The aircraft held a valid Certificate of Airworthiness, and all pre-flight checks, including fuel and weight verification, had been completed successfully.
The investigation focused on the mechanical failure of the pressurization system. It was discovered that the aircraft had experienced similar loss of pressure events in the past, which had been addressed through maintenance. Upon inspection of the system, investigators identified a specific component failure.
Findings
- The primary cause of the incident was a malfunction of the pressurization system during the takeoff phase.
- The decision to perform a rejected take-off was an appropriate response to the loss of cabin pressure.
- The deflation of the tyres was a direct result of high temperatures generated by the braking system during the RTO.
- A faulty pneumatic relay was identified as the contributing factor to the pressurization failure.