What happened
On 2 May 2017, a BK117 A-3 helicopter, registration ZK-IED, was performing a utility operation near the Pāuatahanui Arm of Porirua Harbour. The mission involved transporting 11-metre hardwood power poles from a staging area to prepared holes across the water.
After successfully lifting the first pole, the pilot transitioned the aircraft forward toward the worksite. While attempting to change radio channels to contact ground staff, the pilot experienced a sudden, intense vibration and a sharp rotation of the aircraft to the right. In an attempt to stabilize the flight, the pilot lowered the collective, which caused an unexpected rapid descent. The helicopter subsequently rolled, pitched nose-down, and struck the shallow water. The pilot managed to evacuate the partially submerged aircraft with minor injuries, though the helicopter sustained substantial damage.
The investigation
Investigators examined the aircraft's mechanical state and the pilot's background. No mechanical failures were found to have contributed to the crash. The inquiry also scrutinized the pilot's medical history, discovering that a prescribed medication and an underlying medical condition had not been disclosed to the Civil Aviation Authority (CAA). While there was no evidence the medication caused the accident, the non-disclosure was noted as a significant safety concern.
Furthermore, the investigation uncovered serious discrepancies in the maintenance records of ZK-IED. Specifically, several required inspections and verification tasks had not been completed before the aircraft was issued its certificate of airworthiness. The investigation also revealed that similar maintenance anomalies existed in other aircraft previously owned by the same company.