It was the first fatal commercial aircraft accident investigated by the National Transportation Safety Board in which texting has been implicated. And it underscored the board's worries that distractions from electronic devices are a growing factor in incidents across all modes of transportation - planes, trains, cars, trucks and even ships.
The five-member board unanimously agreed that the helicopter crash was caused by a distracted and tired pilot who skipped preflight safety checks, which would have revealed his helicopter was low on fuel, and then, after he discovered his situation, decided to proceed with the fatal last leg of the flight.
The case "juxtaposes old issues of pilot decision making with a 21st century twist: distractions from portable electronic devices," said board Chairman Deborah Hersman.
The helicopter ran out of fuel, crashing into a farm field in clear weather early on the evening of Aug. 26, 2011, near Mosby, Mo., a little over a mile short of an airport. The pilot was killed, along with a patient being taken from one hospital to another, a flight nurse and a flight paramedic.
One board member, Earl Weener, dissented on the safety alert decision, saying the cases cited as the basis for it - including the medical helicopter accident - were the result of bad decisions by pilots without a direct connection to the use of distracting devices.
Other board members disagreed. "We see this as a problem that is emerging, and on that basis, let's try to get ahead of it," said board member Chris Hart.
The pilot, James Freudenberg, 34, of Rapid City, S.D., sent 25 text messages and received 60 more during the course of his 12-hour shift, including 20 messages exchanged during the hour and 41 minutes before the crash, according to investigators and a timeline prepared for the board.
Most of the messaging was with an off-duty female co-worker with whom Freudenberg had a long history of "frequent, intensive communications," and with whom he was planning to have dinner that night, said Bill Bramble, an NTSB expert on pilot psychology.
Three of the messages were sent, and five were received while the helicopter was in flight, although none in the final 11 minutes before it crashed, according to the NTSB timeline.
The helicopter was operated by a subsidiary of Air Methods Corp. of Englewood, Colo., the largest provider of air medical emergency transport services in the U.S. The company's policies prohibit the use of electronic devices by pilots during flight.
In January, the Federal Aviation Administration proposed regulations prohibiting airline flight crews from using cellphones and other wireless devices while a plane is in operation. The regulations are required by a law passed by Congress last year. Regulations already in place prohibit airline pilots from engaging in potentially distracting activities during critical phases of flight such as takeoffs, landings and taxiing.
In some cases, however, pilots are allowed to use tablet computers containing safety and navigation procedures known as "electronic flight bags," replacing paper documents.
The board concluded Freudenberg was fatigued as well as distracted. He had slept only five hours the night before, and the accident occurred at the end of his 12-hour shift.
He was told when he came on duty that the helicopter was low on fuel. But later in the day he missed several opportunities to correct the fuel situation before he took off for a hospital in Bethany, Mo., the first leg of the trip. Among those missed opportunities were failing to conduct a pre-flight check and to look at the craft's fuel gauge. Shortly after takeoff, he radioed that he had two hours of fuel. He apparently realized his mistake later during the flight.
While waiting on the ground in Bethany for the patient and the medical crew, Freudenberg exchanged text messages as he was reporting by radio to a company communications center that the helicopter was lower on fuel than he had originally thought. He told the communications center he had about 45 minutes worth of fuel, which investigators said they believe was a lie intended to cover up his earlier omissions and that he was in jeopardy of violating federal safety regulations.
In fact, the helicopter had 30 minutes of fuel left, investigators said. Federal Aviation Administration regulations require 20 minutes of reserve fuel at all times.
With no other place nearby to refuel, Freudenberg opted to continue the patient transfer to a hospital in Liberty, Mo., changing his flight plan enough for a stop at an airfield 32 minutes away for fuel. The helicopter stalled and crashed 30 minutes later.
A low fuel warning light might have alerted him to his true situation, but the light was set on "dim" for nighttime use and may not have been visible. A pre-flight check by the pilot, if it had been conducted, should have revealed the light was set in the wrong position, investigators said.
Although the pilot wasn't texting at the time of the crash, it's possible the messaging took his mind off his duties and caused him to skip safety steps he might have otherwise performed, said experts on human performance and cognitive distraction. People can't concentrate on two things at once; they can only shift their attention rapidly back and forth, the experts said. But as they do that, the sharpness of their focus begins to erode.
"People just have a limited ability to pay attention," said David Strayer, a professor of cognitive and neural science at the University of Utah. "It's one of the characteristics of how we are wired."
"If we have two things demanding attention, one will take attention away from other," he said. "If it happens while sitting behind a desk, it's not that big of a problem. But if you are sitting behind the wheel of a car or in the cockpit of an airplane, you start to get serious compromises in safety."
In October 2010, two Northwest Airlines pilots overflew their destination of Minneapolis-St. Paul International Airport by 100 miles while they were engrossed in working on flight schedules on their laptops.
A text message - especially one accompanied by an audible alert like a buzz or bell - interrupts a person's thoughts and can be hard to ignore, said Christopher Wickens, a University of Illinois professor emeritus of engineering and aviation psychology. If the subject of the email is especially engaging, or especially emotional, that also makes it hard to ignore, he said.
The helicopter pilot didn't have a history of safety problems and was regarded as a good, safe pilot by his co-workers. He was a former Army pilot, and NTSB investigators said his actions on the day of the accident were apparently "out of character."