Mechanical failure of a Virginia State Police helicopter’s main rotor system or tail rotor likely caused it to spin out of control and crash, killing two state police aviators who had been monitoring the Aug. 12 white nationalist rally in Charlottesville, according to one aviation expert.
“The only reason that a helicopter stops flying from a nice straight-and-level altitude and course is if something goes wrong mechanically,” said Robert Hadow, who reviewed a preliminary report on the crash released Tuesday by the National Transportation Safety Board.
Hadow is a 20-year certified flight instructor based in New Jersey who has 5,000 hours of fixed-wing pilot experience and has taken an interest in last month’s fatal crash of the Bell 407 helicopter.
State police Lt. H. Jay Cullen, 48, who was piloting the helicopter, and Trooper-Pilot Berke M.M. Bates, 40, who was operating the helicopter’s camera, “weren’t doing anything that was unusual,” such as landing or taking off, when the aircraft began to continuously spin and descend in a nose-down pitch into trees, according to Hadow’s reading of the eight-page report.
State police declined to comment on whether the agency believes Hadow’s analysis is a plausible explanation for what happened, based on the report.
“The Virginia State Police appreciates the professionalism and comprehensive investigative efforts of the NTSB during all aspects of this incident,” spokeswoman Corinne Geller said.
An NTSB spokesman could not be reached for comment late Tuesday.
Hadow said the engine in the Bell helicopter drives what are essentially two propellers — the main rotor blade system and the tail rotor system.
“And there was no indication that anything was broken between the engine and the main rotor system — according to the report,” Hadow said.
But a more complicated function is how power goes through the shaft and into another gear box in the helicopter’s tail, Hadow explained. The tail rotor is what keeps the helicopter from turning to the right or the left continuously, he added.
The helicopter began to spin or rotate around its vertical axis and then descend in a 45-degree nose-down attitude — continuously spinning — before it was no longer visible below the tops of surrounding trees, according to the report, which cited a “preponderance of witness statements.”
When a helicopter is spinning or continuously turning to the left or to the right, “it means there is something wrong with the tail rotor — either it’s not doing enough of its job or too much of its job,” Hadow said.
“And before (the helicopter) crashed, it was turning to its side,” Hadow added.
The NTSB said the “whole helicopter made a turn, but they didn’t say whether it was spinning to the right or to the left,” Hadow said. “And that would tell you whether the tail rotor was broken, or whether the main rotor system broke.”
Hadow believes one of the most interesting pieces of evidence could be security camera footage that investigators obtained from the University of Virginia. The video, according to the report, corroborated statements by witnesses regarding the spinning of the helicopter during its descent. Hadow said that could be central to the investigation.
“A rotation about the vertical axis indicates a failure of the tail rotor, or the failure to control it,” Hadow said. “A dollar to a donut, (the crash is the result of) a mechanical failure.”
The report summarizes factual information collected during the early stages of the investigation and does not contain any analysis or probable cause for the crash.
In a news release, the NTSB highlighted these facts contained in the report:
• Radar data indicated that just prior to the accident, the helicopter was flying north-northwest at an altitude of approximately 2,200 feet above mean sea level before it began to turn to the right and descend rapidly.
• Security camera video shows the helicopter spinning in a nose-down pitch attitude before it descended into trees.
• All the main helicopter components were recovered at the accident site, but most were damaged by crash forces and a post-impact fire.
• The debris field was several hundred feet long. The fuselage came to rest on the ground, the tail rotor was located in a tree, and some components of the helicopter were recovered from the roof of a nearby house.
• No evidence was observed to suggest that the helicopter was struck by another aircraft, animal or object.
• The wreckage was retained by the NTSB for further examination.
The report said that airworthiness records from the Federal Aviation Administration, along with the Bell 407’s maintenance records, showed that the helicopter’s most recent 100-hour inspection was completed on Aug. 3. At the time of the accident, the helicopter had accrued approximately 6,000 total hours of operation.
The aircraft was heavily damaged in 2010 when it lost power shortly after takeoff in Abingdon and made an emergency hard landing, but neither the pilot nor co-pilot was injured. State police have said the helicopter “was fully repaired by Bell Helicopter” afterward, and the incident was not mentioned in NTSB’s preliminary report.
The final federal report won’t be available for 12 to 18 months.
The aircraft, known as Trooper One, was one of two state police helicopters circling above Charlottesville on Aug. 12 to relay video of the white nationalist rally and the ensuing violence to officers on the ground.
After flying over the city until 4:42 p.m., Trooper One was re-tasked with providing over-watch security for Gov. Terry McAuliffe’s motorcade. One minute later, the crew advised the VSP command center that they heading directly to the motorcade, about 30 seconds away.
At 4:49 p.m., the second VSP helicopter notified the police command center that Trooper One had crashed.