The National Transportation Safety Board says a helicopter struck a utility wire before a crash that killed a Georgia pilot and an Alabama man last month.
The board's preliminary report says the chopper went down after hitting a wire strung between transmission towers in Tuscaloosa County near Northport.
The helicopter was checking the utility lines when it crashed.
The accident killed pilot Matthew Wallace of Hiram, Georgia, and Alabama Power Co. employee David Carson of Tuscaloosa.
The federal agency says the helicopter left the Tuscaloosa airport the morning of Aug. 19 to inspect high-tension power lines for damage from a storm the previous night. The helicopter crashed about 30 minutes later.
Alabama Power detected a fault on the line, and searchers later found the wreckage nearby.