The CEO of a helicopter company says federal investigators are wrong to blame his mechanic for a 2007 tour helicopter crash on Kauai that killed four people.

Heli USA Airways CEO Nigel Turner on Friday claimed maintenance personnel correctly tightened a clevis pin fastener on the flight control servo.

The National Transportation Safety Board report on the accident Thursday said the fastener wasn't tightened properly.

Turner says the NTSB should take a closer look at the helicopter's manufacturer, American Eurocopter, which issued a bulletin lowering tightness recommendations to the level used by Heli USA Airways' mechanic.

Turner says the NTSB too frequently targets mechanics or pilots rather than investigating the true source of a problem.