A helicopter crash last year that injured five people on the Makawao estate of celebrity chef Bev Gannon was caused by a pilot's mistake, the National Transportation Safety Board has determined.

The April 20, 2007, crash of the chartered helicopter was the result of the pilot's "improper decision to take off downwind in a confined landing zone" at a time when winds were gusting up to 30 mph, the NTSB said this week.

The helicopter was one of two dispatched to Gannon's estate to shuttle passengers from the remote home. The pilot told NTSB investigators that he had spoken twice to company officials before the flight about the problems involved in taking off in the area during high winds.

The NTSB said the pilot's decision to go ahead with the takeoff resulted in a failure to attain proper lift, thus leading to a loss of control of the helicopter.

Witnesses at the time said the helicopter appeared to have hit a jacaranda tree at a height of 10 to 20 feet, then crashed back to the ground with a loud noise. No one was seriously injured.

In another helicopter crash that occurred one day earlier on O'ahu, the NTSB said mechanical failure was the probable cause.

The K&S Helicopters Hughes 369D helicopter chartered for aerial surveillance by the Honolulu Police Department made a hard landing on approach to Turtle Bay's heliport after losing power at about 100 feet, the NTSB said. Two of four people aboard suffered minor injuries.

An investigation revealed that cracks in an oil line resulted in the loss of engine lubrication, leading to the seizure of the power turbine, the NTSB said.