HAWAII (HawaiiNewsNow) - A fatal 2016 helicopter crash into Pearl Harbor was the result of faulty maintenance, according to a report from the National Transportation Safety Board.
In February 2016, a commercial pilot was giving a local air tour with four passengers on board when he noticed that the cabin was vibrating. The pilot began charting course for the nearest airport destination, but when the vibration stopped, he continued the tour.
The vibrating soon returned accompanied by a grinding sensation. When the pilot re-initiated an emergency landing, the helicopter lost lift and fell from the sky 20 feet above the water near Pearl Harbor.
Three of the passengers were able to exit the helicopter, but one remained trapped in the middle seat. The crash resulted in the death of a 16-year-old passenger and three serious injuries, as well as one minor injury.
A post-accident examination of the helicopter revealed that the engine-to-transmission drive shaft was separated on the transmission side. Further examination found that the shaft wasn't properly lubricated and exposed to elevated temperatures, according to the NTSB report.
The National Transportation Safety Board determined that this oversight resulted in a low main rotor rpm (rotations per minute) and the helicopter's crash into water.
"It is likely that, when this maintenance was conducted, grease was not applied to the forward coupling as specified in the manufacturer's maintenance manual," the report reads.
"Further review of maintenance records revealed no entries pertaining to a current annual inspection or 100-hour inspection. Additionally, a component inspection sheet provided by the operator revealed that several required component inspections were overdue and had not been completed at the time of the accident."
NTSB found that the crash may have been prevented with an additional inspection that could have uncovered maintenance issues.