The pilot and a mechanic were the only two people aboard the helicopter. In a statement Wednesday night, Swartz declined to identify the two employees.
"We are thankful that no one else was on the flight and that no one was injured on the ground," Swartz said.
The chopper, a Bell Helicopter 222U, came down in a field near South Wyatt Road and U.S. 67.
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"Our first reports were that the aircraft had trouble in the air. There was another aircraft flying in the area that actually landed and tried to render aid, and his report was that the aircraft had started to malfunction airborne and something was coming off of it, and at that point, it had a catastrophic failure and then crashed into the ground," said Midlothian Deputy Fire Chief Dale McCaskill.
Dennis Lauterback Jr., of Quality Aircraft, and his father flew their helicopter to the scene, arriving before first responders. Dennis Lautherback Sr. said they couldn't even see the wreckage at all at first.
"As the grass fire dwindled down, we saw the helicopter -- what was left of it -- right in the middle of the fire," he said.
Much of main fuselage appears to have been consumed by fire. The main rotor blade was spotted several hundred feet away from the charred remains of the fuselage while the tail boom, largely intact and undamaged by fire, was even farther away from the crash site.
The debris was spread over what appeared to be several thousand feet of open grassland, some of which caught fire after the crash.
CareFlite reported that the helicopter had been bought in the last six months and had never been used to transport a patient. The company said it was still working on the aircraft to make sure it was safe.
"When you complete certain maintenance procedures, you fly the aircraft, you have to validate certain systems are working," said Swartz.
Swartz said he didn't know which systems the crew had been working on prior to the test flight. He said CareFlite does not know what caused the crash and it working with authorities to determine what factors may have contributed to it.
FAA spokesman Lynn Lunsford said the weather conditions were clear, so it's too early to tell what might have caused the crash.
"We haven’t had to deal with something of this magnitude -- a death in our family -- in over a quarter-century," Swartz said. "It is, to be very plain, our worst day. We are thankful to the Midlothian Fire Department and other first responders who responded to the scene."
News of the crash spread quickly among members of the local helicopter community.
"There's just a handful of people that fly them, operate them and own them, you know," Dennis Lauterback Jr. said. "So the odds are, we'll probably know the guys that were on the flight.
The Bell 222U is a modified version of the twin-engine 222 with the principal difference being that the 222U has a landing skid instead of retractable wheels. With the skid, the fuselage can be modified to carry more fuel. The 222U was in production from 1983 to 1995, according to articles published on Wikipedia.
"We extend our heartfelt condolences to the families and friends of those who died. Bell Helicopter will be cooperating fully with the FAA and NTSB in their investigation of the crash. Under NTSB rules, we cannot comment on the investigation," Thomas Dolney, of Bell Helicopter Textron Inc., said in a statement Wednesday.
Omniflight Helicopters said in a statement that it had sold the helicopter to CareFlite on March 5. The company said it had operated the chopper in front line service since August 2001.
"At the time of the sale, all aircraft records were turned over to the new registered owner," Omniflight Helicopters said. "The aircraft was in airworthy condition and was sold in our continuing effort to standardize our aircraft fleet.”
Omniflight Helicopters, an air medical services provider based in Addison, said it was "deeply saddened" by the crash.
CareFlite is a nonprofit EMS service based in Grand Prairie that specializes in air transport.
NTSB Pushes for Improving Safety of EMS Flights from March 25, 2010
Improving the safety of emergency medical services flights has been on the National Transportation Safety Board's "most wanted improvements" list since 2008, a year when the industry suffered a record number of fatalities.
There were 41 people killed in 11 EMS helicopter accidents between December 2007 and February 2010, according to an NTSB report.
It said the pressure that crews face to respond quickly during difficult flight conditions, such as darkness or bad weather, has led to increased fatal accidents.
"What you see happen a lot is, you have aircraft that are being used in very difficult conditions -- a lot of times in the middle of the night, weather is bad and things like that -- and you push them into sort of dangerous situations, and crashes occur," said Kent Krause, a Dallas aviation attorney.
"You also may not have pilots that are as trained as they may be either in the military or some other areas, and then also whether the people operating the helicopters really have the wherewithal, the financial resources, to maintain the helicopters properly so that they operate properly," Krause said.
Last fall, the NTSB urged the government to impose stricter controls on emergency helicopter operators, including requiring the use of autopilots, night-vision systems and flight data recorders.
NBCDFW's Scott Gordon, Kevin Cokely and Omar Villafranca contributed to this report.
A National Transportation Safety Board official says a team of 10 has been assembled to investigate the CareFlite crash that killed a pilot and mechanic Wednesday.
NTSB air safety investigator Tom Latson said it's too early to say why the helicopter went down in Midlothian during a maintenance run. The pilot and mechanic were killed.
CareFlite president and CEO Jim Swartz said no patients were aboard the aircraft. Swartz said the helicopter was on a maintenance check flight that had departed CareFlite's home airport, Grand Prairie Municipal.