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Air ambulance safety is under intense scrutiny as accidents increase, particularly those involving helicopters operating in difficult conditions

Frequently arcane, US federal aviation regulations – FARs – have evolved over the decades to address the realities and requirements of a wide spectrum of operations. The evolution – and proliferation – of regulations is frequently in response to safety issues and the latest operating sector to come under scrutiny is emergency medical service (EMS).

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© JASON RANDALL

The NTSB wants to see a better system of trip risk assessment at dispatch
A recent spate of accidents prompted a special investigation by the US National Transportation Safety Board (NTSB), which in January made four recommendations to the Federal Aviation Administration to improve EMS safety. Perhaps the most significant of these is the call for all EMS flights with medical crew on board to be operated under FAR Part 135 regulations, even when there is no patient on board.

NTSB board members at the 25 January public hearing on the special report questioned why some EMS flights are allowed to be conducted under Part 91 private operator rules, while others are required to be flown under more stringent Part 135 on-demand operator regulations. “That sounds more like a bingo game than sound policy,” said member Ellen Engleman Connors.

In the early 1990s, NTSB investigation of regional airliner accidents produced a series of recommendations that resulted in the FAA’s “One Level of Safety” initiative and the so-called “Commuter Rule” that required all scheduled carriers operating aircraft with as few as 10 seats to upgrade from Part 135 to the Part 121 standards applied to major airlines operating large aircraft.

Now the “duality” in EMS operations is drawing similar criticism from the NTSB. ”That Part 135 is required when carrying a patient or organ, but not medical crew, is a ridiculous loophole that needs to be closed,” said board member Deborah Hersman. But closing the loophole may not be simple.

That less stringent rules apply for operations without patients on board is one of four safety issues identified by the NTSB’s special review of 55 EMS accidents that occurred in the USA between January 2002 and January 2005 – a number not seen since the 1980s, the board says. The 41 helicopter and 14 fixed-wing accidents resulted in 55 fatalities and 18 serious injuries, with another 23 fatalities in nine additional accidents that have occurred since January 2005.

The NTSB last studied EMS safety in 1988, after a string of 59 accidents between May 1978 and December 1986. That review resulted in a 1991 FAA advisory circular on helicopter EMS operations and a subsequent reduction in the number of accidents. But the air medical industry has grown dramatically since 1991 and the accident rate is again increasing.

Data deficit

One problem operators and regulators face in addressing safety is that there is no reliable measure of EMS operations. Estimating that the hours flown by EMS helicopters increased from 162,000 in 1991 to 300,000 in 2005, while the fleet grew to between 650 and 750 aircraft, the NTSB believes the accident rate is increasing but the industry itself “doesn’t know”, says Dawn Mancuso, executive director of the Association of Air Medical Services (AAMS). “There is no required reporting of flight hours,” she says.

AAMS is this month launching a web-based database and has the industry’s commitment to confidential reporting of operator activity. “That will allow us to formalise a rate,” Mancuso says. “We have seen an increase in accidents but there has also been a huge increase in the number of assets.” That suggests there is much more EMS flying today but, for now, “that remains pure conjecture”, she says.

Lacking a statistical basis for its study, the NTSB highlighted seven accidents that illustrated the four safety issues identified. The crash of an AgustaWestland A109A in California in December 2003 and a Beech King Air B90 in Kansas in February 2004, illustrated the need for all operations to be under Part 135, the report says.

The A109A hit a mountain in high winds and heavy rain while en route to pick up a patient, killing the pilot and two flight nurses. The King Air hit terrain while on a repositioning flight, killing the pilot, a paramedic and a nurse who had been on duty for 14h and awake for 21h at the time of the accident. In all, 35 of the 55 accidents occurred in Part 91 operations with medical crew but no patients on board.

There are no duty-time restrictions under Part 91 and significantly stricter weather requirements under Part 135, the NTSB says. EMS operators can fly positioning flights – which often carry medical crew – under Part 91 but must follow Part 135 procedures when patients or organs are on board. “The NTSB does not believe EMS should be allowed to operate under Part 91 just because there is not a patient aboard,” Jeff Guzzetti, NTSB deputy director for regional operations, told the public hearing. “Operations should not be differentiated. The safety of EMS operations would improve if the entire flight plan is Part 135.”

But under Part 135, AAMS says, operators cannot fly under instrument flight rules (IFR) to pick up a patient at a location that does not have FAA-approved weather reporting. “The most important issue is access to the IFR system en route to a place without official weather reporting,” says Mancuso. “The only options are not to fly, or to fly visual flight rules.” AAMS and other industry organisations will meet with the FAA in March to discuss weather reporting requirements.

Citing the January 2003 Utah crash of an A109K2 at night in dense fog and the January 2005 Wyoming crash of a King Air E90 at night in icing, the NTSB wants the FAA to require all EMS operators to implement flight risk evaluation programmes.

“None of the operators in the 55 accidents had a risk evaluation programme,” said Guzzetti. In all, 13 of the accidents would not have occurred if flight risk evaluation had been in place, he says: “They would have been rejected or the risk mitigated.” A guidance document was issued by the FAA in August, but the NTSB “wants a requirement not a recommendation”, says Mancuso.

Enhanced vision

The March 2004 Texas crash of a Bell 407 that hit terrain while manoeuvring in reduced visibility, and the July 2004 South Carolina crash of a 407 that hit trees after picking up a patient from a road accident, highlight the need for formal despatch and flight-following procedures, says the NTSB. “A flight despatcher with aviation-specific knowledge was missing in 11 of the 55 accidents,” says Guzzetti.

The last of the four recommendations is that EMS operators be required to install terrain awareness warning systems (TAWS), as illustrated by a Bell 407 that hit Nevada’s Battle Mountain in August 2004 while returning with a patient under Part 135. The NTSB believes TAWS could have prevented 17 of the 55 accidents, but the AAMS believes the board underestimates the cost of the system and overestimates it effectiveness on helicopters. “Is this the best use of resources?” Mancuso asks.

The NTSB says night-vision imaging systems might have helped in 17 of the accidents but stopped short of recommending their use because image-intensifying night-vision goggles (NVG) do not work in urban areas. Some EMS operators are already using NVGs. Mancuso says AAMS plans a workshop later this year to study available technologies, including infrared enhanced vision systems.

GRAHAM WARWICK / WASHINGTON DC