"It's certainly technologically possible and economically feasible," Sanger said.
At the crash site yesterday, officials with the NTSB, Federal Aviation Administration and the state police were scouring the wreckage in search of clues to what happened. About 20 people, including investigators and employees of the helicopter's manufacturer, briefly halted their work as a photographer and videographer from the news media were shuttled to the site in a golf cart to capture images of the downed helicopter.
Deborah A.P. Hersman, a member of the NTSB, said the debris is contained within a 200-yard area inside Walker Mill Regional Park, adding that the helicopter's main components are "accounted for, but heavily damaged," indicating the aircraft did not encounter fire or an in-flight break-up.
Crews discovered cockpit instruments outside the aircraft that show the helicopter was en route to the Andrews runway, Hersman said. So far, a thorough investigation of the instrument landing system, which enables the pilot to land the aircraft, showed normal operations, she said.
Hersman said that emergency medical services missions are among the riskiest helicopter flights. She said the agency has investigated eight fatal EMS accidents in the past 12 months involving 31 deaths.
"We are very concerned about this segment of the industry, and that's why we sent a whole team here," Hersman said.
She would not say whether poor visibility and foggy weather were responsible for the crash, though she noted that conditions were better when the copter took off than when it crashed. She did say that for years, the NTSB has warned EMS flight operators to take full stock of weather conditions before flying.
"We would like to see TAWS installed on all EMS operations so they can have adequate clearance of obstacles and avoid terrain," she said.
The dangers of EMS flights at night and in poor weather were pointed out in a 2006 study by the Center for Injury Research and Policy at the Johns Hopkins University Bloomberg School of Public Health. The study found that 56 percent of EMS helicopter crashes in darkness involved fatalities, compared with only 24 percent that occurred during the day.
Weather was found to be an even more dangerous factor. When pilots were flying under conditions requiring the use of instruments, 77 percent of crashes were fatal compared with 31 percent of crashes that occurred during conditions of good visibility.
