What happened
On the morning of January 7, 1997, a Polynesian Airlines DHC-6 Twin Otter, registration 5W FAU, crashed into the western slopes of Mt Vaea near Apia. The aircraft was performing a scheduled service from Pago Pago to Fagali'i. After completing an instrument approach at Faleolo, the crew attempted to navigate toward Fagali'i using visual references. However, the flight encountered heavy rain and low cloud cover during the transit. The impact resulted in three fatalities, including the captain and two passengers, while the first officer and one passenger survived the accident.
The investigation
The investigation focused on the flight conditions and the crew's navigation during the period of reduced visibility. Investigators examined the transition from instrument flight to visual flight rules (VFR) and how the aircraft's path was maintained despite the deteriorating weather. The inquiry established that the aircraft entered cloud layers while attempting to navigate via ground features.
Findings
Several critical factors contributed to the crash. The primary cause was the captain's decision to proceed toward Fagali'i while operating in reduced visibility and subsequent cloud cover. This decision led to a lack of adequate visual reference, which caused the crew to either misidentify ground landmarks or maintain an incorrect heading and altitude. Ultimately, the heavy rain and low cloud meant there was insufficient forward visibility to allow the crew to recognize and take timely action to avoid the terrain.
Safety action
Following the investigation, safety recommendations were issued to the airline's Chief Executive Officer. These focused on establishing clear company guidance to ensure all VFR flights between Faleolo and Fagali'i maintain a flight path that stays well clear of significant obstacles and high ground. Additionally, the report emphasized the need for improved flight deck communication and the adoption of Flight Safety Foundation resources to help prevent controlled flight into terrain (CFIT) accidents.