What happened
On February 14, 2020, a scheduled flight operated by a Boeing 73 7-800, registration SP-ENL, was en route from Las Palmas Grand Canaria (GCLP) to Warsaw Chopin Airport (EPWA). While cruising at flight level FL380 near the UTELA waypoint within the LFFF UIR airspace in France, the crew observed several simultaneous cockpit warnings, specifically "MASTER CAUTION+AUTOFAIL+ALTN."
In response to these alerts, the crew implemented the "AUTO FAIL OR UNSCHEDULED PRESSURIZATION CHANGE" checklist. Following the execution of these procedures, the cabin pressure remained stable and within normal parameters. The aircraft continued its flight plan, completing the descent and approach into Warsaw without further complications.
The investigation
The investigation focused on the technical malfunction that triggered the cockpit warnings. The captain recorded the malfunction in the Electronic Technical Logbook (eTLB). Maintenance personnel from the operator's servicing organization inspected the aircraft on the same day and identified a failure in the controller unit, specifically a "CONTROLER LRU FAIL on CPC #1." The fault was rectified in accordance with the approved technical documentation.
Findings
- The primary cause of the event was a malfunction of the CPC #1 controller LRU.