What happened
On 28 November 2012, a Bell 407 helicopter, registration PK-WSC, was conducting a functional test of its autopilot system following recent maintenance. Operated by PT. Whitesky Aviation, the flight departed from Sepinggan Airport in Balikpapkan, Indonesia, with a crew including a pilot, an engineer, a flight operation officer, and three off-duty employees.
During the return leg of the mission, the pilot encountered heavy rain near Penajam Bay. To maintain visual contact with the terrain under Visual Flight Rules (VFR), the pilot descended from 1000 ft ASL to as low as 100 ft ASL. At approximately 0805 UTC, the crew heard an unusual sound and performed a 180-degree turn to investigate. Upon inspection, the pilot observed a sailing speedboat and believed the helicopter's landing skid had made contact with the vessel.
Because the aircraft's instruments showed no operational issues and the speedboat continued its course, the pilot proceeded to land safely at Sepinggan Airport. However, local search and rescue authorities later confirmed that the collision had occurred, resulting in one fatality involving the motorist operating the speedboat. The other seven passengers on the vessel survived.
The investigation
The investigation focused on the sequence of events leading to the contact between the aircraft and the watercraft. Investigators examined the flight path, the weather conditions involving heavy rain, and the altitude of the helicopter at the time of the incident. The inquiry also reviewed the operational procedures of the helicopter operator and the nature of the speedboat's service in the Penajam Bay area.
Findings
- The helicopter was operating at an extremely low altitude of approximately 100 ft ASL to maintain visibility through heavy rain.
- The helicopter landing skid collided with the body of the speedboat motorist during the low-altitude flight.
- There was no visible damage to the Bell 407 or the speedboat following the impact.
- The pilot's decision to descend to 100 ft ASL was driven by the need to remain below cloud cover and maintain visual references during inclement weather.
Safety action
Following the incident, the NTSC issued a recommendation to PT. Whitesky Aviation to strictly enforce flight operation procedures, specifically regarding VFR operations during periods of marginal visibility. The operator has since implemented safety notices and conducted crew training focusing on Crew Resource Management (CRM) and Approach and Landing Accident Reduction (ALAR).