Investigators who combed the wreckage of a fatal Las Vegas sightseeing helicopter crash in December say critical steering hardware was disconnected, and the bolt and other tiny parts that should have secured it weren't found on the scene.
The finding was among documents released Friday by National Transportation Safety Board officials investigating the Dec. 7 twilight crash, which killed a 31-year-old pilot, two honeymooners from India, and a Utica, Kan., couple that was celebrating their 25th wedding anniversary.
Gary C. Robb, who is suing tour operator Sundance Helicopters Inc. on behalf of the four tourists' families, said the details brought "a little bit" of closure for his clients, "but it doesn't bring their loved ones back."
Investigators say a rod became disconnected from the machinery that controls the blades' lateral movement, letting the pilot move the helicopter side-to-side. The bolt, nut and pin that would have secured the parts and connected the pilot's steering joystick to the rotor mechanism have not been found.
A failure there could explain the helicopter's erratic climb, turn and dive before the crash, Robb said. Robb suspects the missing bolt _ which measures less than an inch and is reinforced with a pin about 1/8 inch long _ jiggled loose and caused the pilot to lose control. He said he suspects Sundance mechanics didn't secure the bolt correctly.
Safety officials have still not ruled on the cause of the accident. Sundance Helicopters CEO Larry Pietropaulo did not immediately return a call seeking comment.
Records show the mechanism was overhauled the day before but passed multiple inspections on the day of the crash. The helicopter was working fine when it took tourists on two daytime tours along the same route.
The report also describes a terrified shriek a fellow tour company pilot heard over the radio about 30 seconds before he saw smoke.
The fellow pilot says he heard the scream of a man cutting in and out moments before impact.
The crash killed 28-year-old Lovish Bhanot and 26-year-old Anupama Bhola, newlyweds from India. It also killed Kansas tourists Delwin and Tamara Chapman, who were both 49 and vacationing for their anniversary.
Las Vegas pilot Landon Nield, 31, who grew up in Wyoming and Utah and was married six months earlier, was also killed.
The ride was a Sundance Helicopters Inc. "Twilight Tour," which takes tourists over the Hoover Dam and the Las Vegas Strip at sunset. Aerial sightseeing is big business in Las Vegas, with four operators at McCarran International Airport averaging more than 1,500 passengers per day and ticket prices often starting above $200 each.
Passengers who took a tour with Nield the same day in the same aircraft said their pilot was in a good mood, happy, and chatty, and never made them feel unsafe.
Nield's wife told investigators her husband was getting normal sleep hours in the days before the accident, and had walked his children to the bus stop and helped her with chores before he went to work on the crash day.
In the documents, a Southern Nevada Water Authority employee near the crash site said he hear an unusual helicopter sound _ similar to a pilot gunning its engine and the engine screaming or redlining _ before he heard a muffled thud and saw a black plume of smoke rising from a mountainous ravine, some 14 miles outside Las Vegas.