What happened
On June 3, 2016, a Cessna 525 operated by Jet Story sp. z o.o. was performing a takeoff roll from runway 18 at Riga Airport (EVRA), Latvia. During the takeoff roll, the crew observed significant fluctuations in the Interstage Turbine Temperature (ITT) of the left engine, with readings oscillating between 830°C and 860°C over a five-second period. In response to these high temperature indications, the crew aborted the takeoff at a speed of approximately 70 knots. The scheduled flight was subsequently canceled.
The investigation
Following the incident, technical personnel conducted a borescope inspection of the left engine in consultation with the engine manufacturer. The inspection revealed no structural defects or internal damage. Based on guidance from the manufacturer, the engine was deemed airworthy provided the ITT had not exceeded 860°C. After verifying the integrity of the bleed air system, the aircraft was cleared for service. However, maintenance crews identified significant contamination within the interior of the left engine. Under the direction of the CAMO (Continuing Airworthiness Management Organization), the engine underwent a thorough cleaning process. This maintenance resulted in a measurable improvement in performance, with takeoff ITT temperatures decreasing by approximately 30°C.
Findings
- The primary cause of the temperature fluctuations was engine internal contamination.
- The cleaning of the left engine successfully stabilized the ITT readings.
- Maintenance personnel recommended that the right engine also undergo a cleaning procedure to prevent similar occurrences.