What happened
On 03 July 2020, an ATR 72-212A 600 Series aircraft, registration PK-WHY, operated by PT. Wings Abadi Airlines, experienced a significant electrical malfunction during a scheduled flight from Pattimura International Airport, Ambon, to Babo Airport.
Shortly after the aircraft became airborne, the flight crew observed that all five Display Units (DU) and the Integrated Electronic Standby Instrument (IESI) went blank. Simultaneously, all VHF radios ceased functioning, and the landing gear could not be retracted. Due to the loss of primary flight instruments, the pilot was forced to fly the aircraft visually.
After approximately one minute, radio communications were partially restored and the displays began to recover intermittently, though error marks appeared on several altitude and speed indicators. The crew eventually decided to return to Ambon. During the approach, deteriorating weather conditions forced a go-around. After holding for approximately 90 minutes, the aircraft eventually landed safely at Ambon with no injuries and no damage to the airframe.
The investigation
The KNKT investigation focused on the sudden electrical failure and the subsequent loss of cockpit instrumentation. Investigators examined the aircraft's electrical components, including the Bus Power Control Unit (BPCU), push button switches, and various relays.
At the time of the preliminary report, the aircraft had been grounded for troubleshooting. Initial maintenance inspections by the operator returned a "No Fault Found" result regarding the electrical issues. The investigation also reviewed meteorological data, which showed rain and low visibility in the area at the time of the incident.