What happened
On March 11, 2016, while a Boeing 787-80/Dreamliner was descending at flight level 140, the crew observed an "ENGINE SURGE" message on the Engine Indication and Crew Alerting System (EICAS). The flight crew responded by following the appropriate checklists, which successfully cleared the alert.
During the subsequent approach and landing phase, the crew continued to monitor engine parameters and noted fluctuations in the power output of the right engine. Following the landing, the technical issue was reported to ground maintenance personnel and recorded in the aircraft's technical logbook.
The investigation
The investigation established that the "ENGINE SURGE" alert was a false indication. The root cause was identified as the accumulation of moisture within the P26 and P30 sensing lines. Despite the presence of moisture separators, water bypassed these components and reached the Electronic Engine Controls (EEC), triggering a "P30 CROSS CHECK FAULT."
Maintenance actions taken to rectify the issue included suctioning moisture from the lines, which removed 30 ml of water from the P30 line and 3 ml from the P26 line. Additionally, the P30 flexible hose was replaced. Following these procedures and inspections conducted in accordance with the Flight Interruption Manual (FIM), the aircraft was cleared for continued service without restrictions.
Findings
- The primary cause of the incident was the accumulation of water in the P30 and P26 lines, which generated the erroneous engine surge message.