What happened
On the afternoon of October 8, the aircraft known as Prong 33 departed from Phù Cát for a scheduled seven-hour RDF mission. Shortly after departure, approximately 20 minutes into the flight, the pilot notified air traffic control of an intention to return to base due to malfunctions with the Doppler navigation equipment. While the aircraft landed safely and the Doppler system was repaired, technicians discovered that the weather radar was non-functional.
Despite deteriorating meteorological conditions in the operational area, the pilot received instructions to proceed with the mission, provided the flight returned before nightfall. Upon reaching the designated mission area, the crew determined that the weather conditions were too severe for safe operations and began a return flight toward the coast to reach Phù Catus. During this approach, the pilot reported an inverter fire, which subsequently led to the loss of the gyroscopes and attitude indicators.
As the aircraft continued its approach under the guidance of a GCA controller, all radio and radar communication was lost. Following the disappearance, search and rescue efforts were significantly obstructed by poor visibility and heavy weather. On October 12, a SAR helicopter located the wreckage approximately 15 miles southeast of Phù Cát. The accident resulted in six fatalities.
Findings
- An onboard fire involving the inverter occurred during the final approach phase.
- The fire caused a critical failure of essential flight instruments, including the attitude indicators and gyros.
- Instrument failure occurred while the aircraft was operating in adverse weather conditions.