04-O-2021-12.2

Isi rekomendasi

The aircraft was installed with Sandel ST3400 Terrain Awareness and Warning System (TAWS)/Radio Magnetic Indicator (RMI) which provided alerts of Forward-Looking Terrain Avoidance (FLTA) and Premature Descent Alert (PDA). The alert system of ST3400 TAWS/RMI includes an annunciation and aural alerts. Prior to the departure, there was no record or report of aircraft system malfunction.The CVR recorded 30 minutes of audio record on four channels with hearable quality. The CVR did not record any aural alert from the aircraft TAWS. The investigation has not determined the absence of the TAWS alert. However, as the aircraft operating in a mountainous area, the alerts from the TAWS will increase the pilot awareness when flying close to terrain.Therefore, KNKT recommends the aircraft operator to ensure all TAWS installed in their aircraft are functioning and able to generate alert as intended.