What happened
On February 7, 2016, an Embraer ERJ-175 operated by PLL LOT SA was performing its takeoff roll at Warsaw Chopin Airport (EPWA). During the initial phase of the takeoff run, after the initial thrust lever movement but before the auto-throttle had engaged, the crew received a PITCH TRIM SWITCH1 FAIL alert.
Upon detecting this system failure, the crew promptly aborted the takeoff and returned the aircraft to the parking stand. An Air Safety Report (ASR) was filed, and the aircraft was handed over to maintenance personnel for inspection.
The investigation
The investigation, conducted by the operator, focused on the cause of the pitch trim warning. Maintenance crews inspected the aircraft's systems and identified a fault within the Horizontal Stabilizer Actuator Control Electronics (HS ACE). Following the Aircraft Maintenance Manual (AMM) procedures, technicians replaced the HS ACE unit. Following the component replacement, operational tests were performed on the system, which yielded positive results, allowing the aircraft to be returned to service.
Findings
- The primary cause of the incident was a failure of the Horizontal Stabilizer Actuator Control Electronics (HS ACE) unit due to undetermined reasons.
- The crew followed standard operating procedures by aborting the takeoff immediately upon receiving the system alert.