What happened
On July 9, 2015, a De Havilland Canada Dash 8 (400) was performing a takeoff roll at EPPO. During the initial acceleration phase, the flight crew observed a significant discrepancy between the airspeed and altitude indications displayed on the primary and secondary pilot flight instruments. Due to these conflicting readings, the pilot elected to abort the takeoff and returned the aircraft to the parking stand.
The investigation
The investigation focused on the technical state of the aircraft's pitot-static system. It was determined that an issue involving the pressure sensing system had occurred on the previous day. Although maintenance personnel had attempted to rectify the fault by replacing the left-hand pressure receiver, the underlying issue persisted. Following the aborted takeoff, the aircraft was ferried to its home base, where a comprehensive leak test was performed on the static pressure system. This testing revealed a leak in the number 2 static pressure system.
Findings
- The primary cause of the instrument discrepancy was a leak within the number 2 static pressure sensing system.
- The incident was exacerbated by an ineffective repair of a pressure sensing malfunction that had been addressed the day prior to the event.