Factual Information
On 03 July 2020, an ATR 72-212A 600 series aircraft, registration PK-WHY, operated by PT. Wings Abadi Airlines (Wings Air) as flight IW 3544, was conducting a scheduled passenger flight from Pattimura International Airport, Ambon, Indonesia, to Babo Airport, West Papua. The flight was the third of four scheduled flights for the day on the route Ambon–Babo–Ambon–Babo–Ambon. On board were two pilots, one flight attendant, and 49 passengers.
History of the Flight
At 0400 UTC (1300 LT), the aircraft took off from runway 22. After becoming airborne, the pilot verified the Idle Gate lever engaged. Suddenly, all five Display Units (DU) and the Integrated Electronic Standby Instrument (IESI) went blank, and all Very High Frequency (VHF) radios were inoperative. The landing gear could not be selected up. The pilot glanced at the overhead panel and observed several illuminated lights: the SHED light on the DC SVCE/UTLY BUS, the AVAIL light on the EXT PWR push buttons, pack, lavatory detection, and engine boost. The weather at the time was rain with ground visibility of 6 km. Without flight instrument references, the pilot flew visually.
After approximately one minute, radio communication was heard and the DUs intermittently recovered. Cross marks (X) appeared on the speed and altitude indicators on DU 1, DU 5, and the IESI. The landing gear lever could then be selected up. The engine power was reduced from takeoff to climb power, and the crew performed the after-takeoff check list, including flap retraction, and maintained 170 knots.
The pilot attempted an ILS approach, but weather deteriorated, leading to a go-around. The flight held over AUDRI for about 90 minutes at 7,000 feet, then for 20 minutes at 5,000 feet, waiting for weather improvement. After the weather improved, the aircraft landed safely at 0600 UTC. No one was injured and the aircraft was undamaged.
Investigation Status
This preliminary report is based on initial investigation by the Komite Nasional Keselamatan Transportasi (KNKT). At the time of publication, the investigation was continuing. The KNKT had been informed of safety action taken by the Directorate General of Civil Aviation (DGCA) of Indonesia to share information and increase awareness among ATR operators. The KNKT recommended that PT. Wings Abadi Airlines maintain communication with the aircraft manufacturer to obtain necessary information to mitigate the situation. The Bureau d'Enquêtes et d'Analyses (BEA) participated as Accredited Representatives of the State of Manufacturer, with ATR as adviser.
Probable Cause
The preliminary report does not state a probable cause.