Also contributing to the accident, the safety board said Tuesday, was the pilot's likely "self-induced pressure" to please a high-profile client and a bias toward continuing with the established plan.
The fire started in the boat's salon, where divers had plugged in phones and other devices. Investigators pointed to the lack of a night watchman as a reason for high casualty numbers.
The helicopter crash that killed Kobe Bryant and eight others in January has highlighted a decades-old problem in aviation: pilots continuing flights into bad weather rather than landing.