The dangers posed by texting while driving a car have been well documented, and the risks have caused many areas in the US to outlaw the practice. But the dangers of texting while flying have remained out of the headlines — until now. The US National Transportation Safety has recovered evidence that a commercial helicopter pilot was texting before a 2011 crash that killed him and three passengers, the first time texting has been found to occur during a fatal air accident, Bloomberg reported.

The pilot received four texts and sent three in mid-flight

The pilot, who worked for an emergency medical aerial transportation company called Air Methods, received four texts and sent three in mid-flight. At the time, he was transporting a patient and two medical attendants between hospitals. All four were killed when the helicopter went down in Mosby, Missouri. In one of his texts, the pilot told a coworker he was planning on meeting for dinner that he hadn't slept well the previous night. Air Methods told the NTSB it has "clear company policies against the use of personal communications devices while airborne." In a horrific irony, one of the company's own safety programs is called "SMS" (safety management system).

The crash itself occurred after the helicopter ran out of fuel, but Bloomberg speculates that the pilot's failure to to fill his tank with enough fuel before takeoff may have been caused in part because he forgot while paying attention to his texts. The pilot's sleep deprivation may also have played a role, although in Air Methods's submission to the NTSB, the company says it "does not believe that pilot fatigue was a factor in the accident," in part due to the fact the pilot was "texting on his personal cell phone quite prolifically."

For the record, Air Methods also doesn't think texting should have distracted the pilot from "continuing and immediate awareness of something as a critical as his fuel state." The NTSB is due to rule definitively on the cause of the accident, and texting's role in it, tomorrow. Reached by the The Verge, Air Methods declined to comment until after the ruling. Whatever the outcome, it's clear that thumbing a message to friends isn't advisable when operating any sort of heavy equipment, on the ground or in the air.

Update: Air Methods released a statement to The Verge on Tuesday as the NTSB met to go over the findings of its investigation, saying in part "based upon the investigation to date, we have already initiated a number of safety improvements," including instituting a "zero tolerance policy for use of cell phones during flight." Air Methods also said it was "prepared to work with the NTSB and the FAA to raise the bar to ensure the safety of those who fly with us."