A helicopter crash is under investigation after it was revealed the pilot was texting before the flight ran out of fuel and crashed. Four were killed in the wreck, which happened in Missouri. The crash represents the first case where a commercial aircraft crash investigated by the National Transportation Safety Board involving texting. The 34-year-old pilot exchanged 20 texts with an off-duty, female coworker for about two hours before the helicopter collided into a farm field due to running out of fuel. He did not notice the aircraft needed fuel because he failed to conduct pre-flight tests, according to news reports.