What happened
On March 10, 2016, approximately one hour after takeoff, the crew of a Boeing 737-800 observed a "LOW PRESSURE" warning in hydraulic system A. Following established checklists, the crew deactivated the mechanical pump for that system and continued the flight toward the original destination.
Several minutes later, the low-pressure warning re-appeared. Upon further inspection, the crew determined that a total loss of hydraulic fluid had occurred, resulting in zero pressure within system A. After consulting with the operator's flight operations department while within the Warsaw FIR, the crew decided to divert the aircraft to Warsaw Chopin Airport (EPWA).
In accordance with the "LOSS OF SYSTEM A" checklist, the crew utilized the alternative manual landing gear extension method prior to arrival. The crew requested landing priority from air traffic control but did not declare a formal emergency. The landing was completed without further incident, and there were no injuries among the 172 occupants.
The investigation
The investigation, conducted by the operator, focused on the source of the fluid depletion. Maintenance personnel inspected the aircraft and identified that the hydraulic fluid had leaked through a valve within the transducer adapter module.
Findings
- The primary cause of the incident was a faulty seal within the hydraulic system A transducer adapter module.