WASHINGTON -- Federal aviation officials said Monday that they are concerned medical helicopter accidents may again be on the rise now that four fatal crashes have happened in less than six months.
"The recent spate of accidents has the FAA's full attention," said Alison Duquette, spokeswoman for the Federal Aviation Administration.
A helicopter carrying a 58-year-old patient, along with a flight nurse, paramedic and pilot, crashed into a wooded area near Huntsville, Texas, early Sunday, killing all aboard. The helicopter struck trees, spreading debris over 600 feet, according to preliminary data from the National Transportation Safety Board (NTSB).
The accident and three others since Dec. 30 have killed 13 people and are similar to a pattern that prompted the NTSB to conduct a special safety review of the air-ambulance industry in 2006, according to preliminary reports and an industry association.
All four of the recent fatal crashes happened at night and in places where pilots had little or no visual reference on the ground, such as a forest or over water, according to NTSB files.
"We're monitoring all these recent investigations with an eye towards whether they are related to previous recommendations we made," said Jeffrey Guzzetti, deputy director of the NTSB's aviation division.
The NTSB said in 2006 that most crashes were preventable. It issued recommendations for better technology and new rules to force pilots to be more cautious, especially at night and in poor weather.
The FAA, which regulates the air-ambulance industry, has taken numerous steps to improve safety in recent years but has balked at the more stringent suggestions by the safety board.
No accidents are acceptable on the helicopters that increasingly ferry the nation's sickest patients from remote locations to top trauma centers, said Tom Judge, program director for LifeFlight of Maine and a safety adviser to the Association of Air Medical Services.
There is no evidence that the crashes are anything more than an "unfortunate cluster," Judge said. "I think all of us are puzzled and are trying to understand what this is."
"Night continues to be a very big risk area," he said.
After a flurry of attention from crash investigators and regulators, the number of fatal air-ambulance helicopter crashes fell to two in 2006 and two in 2007, according to NTSB data. In 2008, there have been three fatal crashes. Recent crashes include:
*On Dec. 30, in Cherokee, Ala., an air-ambulance helicopter assisting in the search for a missing hunter crashed in a wooded area at night, killing a pilot, paramedic and flight nurse.
*On Feb. 5, a pilot and two medical workers died when a helicopter crashed in a bay near South Padre Island, Texas.
*On May 10, an air-ambulance helicopter crashed into trees near La Crosse, Wis., shortly after dropping off a patient at a hospital. The pilot, a physician and a nurse died.
*An FAA inspector and a pilot suffered serious injuries on May 29 when a helicopter crashed on top of the Spectrum Health Butterworth Hospital in Grand Rapids, Mich.
The pilot was receiving a routine check by the inspector. The crash prompted the evacuation of some hospital patients.
The NTSB recommended that air-ambulance companies adopt new technology to warn pilots when they flew too close to the ground and pay more attention to high-risk factors such as poor weather before departing. The NTSB also voted to encourage the FAA to approve the use of night-vision goggles.
The new technology has proved difficult to put in place, according to FAA documents and Judge.
None of the pilots on the four recent fatal crashes at night was using night-vision goggles, according to Guzzetti.