The ATSB today released its final investigation report into the fatal crash of an EC 135 during a marine pilot transfer in March 2018.
VH-ZGA was on an NVFR mission to recover a marine pilot from the bulk carrier Squireship off the coast of Port Hedland WA when it crashed into the sea during a second approach. An instructor pilot was able to evacuate the aircraft, but a pilot under instruction died in the crash.
The helicopter crew had already aborted one approach to Squireship due to an unstable rate of descent and was positioning the aircraft for a second approach when it impacted the sea.
According to the ATSB report, the EC 135 was put into a descent from 1100 feet without coupling the autopilot's vertical navigation mode, and the pilots did not effectively monitor their instruments, resulting in the helicopter descending below the approach profile with an excessive rate of descent and low forward speed.
Neither pilot responded to the situation until the radio altimeter issued a 300 feet warning.
Although the conditions during the flight met the standards for night VFR, the investigation found that low celestial lighting, and the lack of artificial lighting 20 nm offshore meant the operation was conducted in low light conditions.
“This was a complex investigation, which has already resulted in several safety actions being taken by the operator and the regulator,” said ATSB Chief Commissioner Angus Mitchell.
“Helicopter pilots operating in a degraded visual environment are exposed to a higher workload and a heightened risk of spatial disorientation."
The operator’s training and assessing procedures for marine pilot transfer operations did not provide assurance that pilot under supervision experience, helicopter instrumentation, and instructor capability were suitable for line training at night in these conditions, the investigation found.
“The accident flight was a line training flight, with the pilot under supervision in the right seat, and the instructor in the left seat,” Mitchell explained.
“However, the helicopter’s instruments were set up for a single pilot in the right seat. This limited the instructor’s ability to monitor the flight path and take over control if necessary, particularly in the degraded visual environment.
“For any operation that relies on the instrument flying skills of a second pilot, consideration should be given to the adequacy of flight instrumentation for that pilot.”
Among other findings, the ATSB report states that when operating at Port Hedland in degraded visual conditions, "the instructor had not been able to ensure that circling approaches were consistent with the operator's standard operating procedures.
"This probably limited the support provided to the pilot under supervision on the occurrence flight and, in combination with other factors, probably contributed to the abnormal flight path and partial recovery."
The full accident investigation report is on the ATSB website.