What happened
On 22 September 2001, a PC 6 Pilatus Porter, registered as PK-UCE, was performing a scheduled flight from Pagai toward Wamena under Visual Flight Rules. The aircraft departed at 13:03 local time and was expected to arrive at its destination at approximately 04:36 UTC. During the flight, the pilot followed a standard procedure of communicating position, altitude, and destination via the AFFIS system to the company's flight following officer at Sentani Airport, as well as broadcasting blind transmissions on the Wamena Tower frequency.
As the flight approached the North Gap corridor, the expected progress reports ceased. After the aircraft failed to provide the required update upon passing the corridor and failed to arrive at Wamena by the estimated time, the flight following officer at the Sentani base initiated an alert. Other YAJASI aircraft operating in the vicinity were also notified to assist in a search effort.
The wreckage of PK-UCE was subsequently located in a mountainous area near the Pass Valley airstrip at an elevation of approximately 7,500 feet. The investigation noted that the aircraft had struck trees and the ground. Physical evidence at the site included a broken left wing and propeller blades that were bent rearward and not in the feathered position.
Findings
Investigations into the crash determined that the pilot attempted to descend from a cruising altitude of 10,000 feet to navigate through area weather that was considered marginal. It is believed the pilot's assessment of the weather conditions was inaccurate. The maneuver intended to avoid clouds on the left side of the VFR route likely resulted in the aircraft operating with less-than-required separation from weather elements, failing to meet the necessary minimums for Class F airspace.