Federal investigators say they found main rotor impact marks next to a tail boom that separated from a helicopter just before a crash over Rowlett last month that killed two people.
In a preliminary report issued Thursday, the National Transportation Safety Board said impact marks agents found adjacent to the boom separation were consistent with in-flight contact.
Agents found no evidence of any pre-separation failures. The NTSB has not yet said why they think the rotor struck the Robinson R44's tail boom, causing the failure.
With a separated tail boom there is no way for a pilot to control the helicopter, dooming it to spin and crash. Witnesses reported seeing the helicopter cabin and the separated tail rotor spinning uncontrollably as they fell toward the ground over Rowlett on March 25.
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The FAA and NTSB are leading the investigation. The helicopter was owned by Sky Helicopters. NBC 5 contracts with Sky to fly our helicopter, Texas Sky Ranger.