What happened
On 2 December 2014, an S2R-T3/4 Thrush (registration PK-ELR), operated by PT. Elang Nusantara Air, was conducting a positioning flight from Gorontalo to Ternate. The flight, which was being conducted under Visual Flight Rules (VFR), was diverted to Manado due to deteriorating weather conditions.
At 0138 UTC, the pilot notified Manado Approach of the diversion. By 0200 UTC, the pilot reported being 17 nautical miles from the MNO VOR. However, following this final communication, the aircraft disappeared from radar. A witness on a nearby fishing boat later observed a small aircraft descending steeply at an angle of approximately 60 degrees through heavy rain and cumulonimimbus clouds. The aircraft struck the water near the coastline. While some debris, including landing gear and parts of the elevator, was recovered, the main wreckage and the two crew members were not found.
The investigation
The investigation focused on the aircraft's flight path, the weather conditions, and the mechanical state of the aircraft. Investigators analyzed satellite imagery, which confirmed the presence of heavy rain and significant cloud formations in the area at the time of the disappearance.
Calculations based on the damage to the recovered elevator components and witness testimony suggested the aircraft was in a high-speed dive. The estimated impact speed was significantly higher than the aircraft's structural limitations. The investigation also examined the pilot's qualifications, noting that while the crew was validly licensed, the pilot did not hold an instrument rating, which is critical for navigating through Instrument Meteorological Conditions (IMC).
Findings
- The aircraft was in an airworthy condition prior to the accident, with no evidence of mechanical failure or engine malfunction.
- The flight encountered heavy rain and cumulonimbus clouds, forcing the aircraft into IMC.
- The pilot lacked an instrument rating, making it difficult to maintain control during weather-induced transitions.
- The aircraft entered an unrecoverable dive, likely caused by pilot disorientation while flying through turbulent weather without instrument flight capabilities.