New rules adopted this month to improve helicopter safety were generated by examining the cause of a 2004 crash on Kaua'i that officials determined was linked to pilot error.

A Bali Hai tour helicopter smashed into a steep mountainside on Sept. 24, 2004, killing the pilot and all four passengers.

A National Transportation Safety Board report on the crash said pilot Shankar Tummala, an India native recently from Michigan, who had been flying on Kaua'i only two months, was inexperienced in dealing with the island's changeable weather, and that an understaffed Federal Aviation Administration failed to notice some of his questionable route decisions and warn him.

The fatal crash was on Tummala's eighth flight of the day. He had been in the helicopter nearly eight hours at the time of the crash, had eaten a sandwich while in the pilot's seat and had been seen taking just one break to walk and stretch.

The report said Bali Hai had a policy that encouraged pilots to fly in questionable weather, encouraged them to stay on schedule and encouraged them to fly long hours.

Bali Hai Helicopter Tours went out of business after the crash.

"The operator's pilot-scheduling practices ... likely had an adverse impact on pilot decision-making and performance," the NTSB said in its accident probable cause statement.

Tummala's final flight, scheduled for 45 minutes, left at about 4 p.m. and was to cruise clockwise around the island over Waimea Canyon, the Na Pali Coast, Wai'ale'ale Crater and Manawaipuna Falls, the NTSB report said.

On the day of the accident, Tummala was the only pilot on duty at Bali Hai, and the customer service representative stated that the pilot appeared "fine" when he arrived at the office, the report said.

A passenger on the fourth tour stated that the pilot was "very nice" and "professional" and appeared relaxed as he narrated the tour.

Passengers on the seventh tour, however, stated that the pilot looked "extremely tired" before their flight and that he got out of the helicopter to stretch and walk around.

When the line service technician boarded the four passengers for the eighth tour, he reminded the pilot that this was his last tour for the day.

He stated that the pilot looked "fine" but was wearing sunglasses and that he couldn't see the pilot's eyes or determine if he looked tired, it said.

The NTSB report said the most basic cause of the crash was the 39-year-old pilot's error in flying into deteriorating weather and losing control of the Bell 206B aircraft. Radar indicated his flight grew increasingly erratic in the final 47 seconds of flight, as he flew blind in clouds in a manner the agency said was "consistent with pilot spatial disorientation."

The NTSB report said that had Tummala flown a slightly longer course to the east, he would have been in clear weather.

The NTSB said the FAA's operating restrictions could have contributed to the problem, but also that many pilots did not fully understand either the FAA's regulations or their own company policies on flights.

The helicopter went down just north of Mount Kahili and several miles south of Wai'ale'ale, hitting so hard no one could have survived. Victims included Tummala, Ohio attorney Thomas Huemmer, Ohio nurse Tamara Zytkowski and German tourists Willy Braun and Heike Braun.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.