NTSB report urges TAWS for all EMS, Part 135 helicopters

 - September 28, 2006, 10:18 AM

Terrain awareness and warning systems (TAWS) designed specifically for helicopters may soon be in hot demand, following the January 25 release of a report by the NTSB calling for the FAA to impose tighter safety guidelines for helicopter emergency medical service flights.

The NTSB studied 55 EMS helicopter accidents occurring in the three years from 2002 to 2005 and concluded that TAWS should be installed on all EMS aircraft and that operators should comply with Part 135 regulations on all flights. The NTSB also recommended that the FAA require all EMS operators to use formalized dispatch and flight-following procedures that include a dispatcher with aviation experience who is able to provide pilots with weather information and assistance with flight risk assessment decisions, and that the FAA require all EMS operators to develop and implement flight risk evaluation programs.

NTSB spokesperson Lauren Peduzzi told HAI Convention News that the FAA has 90 days to respond to the NTSB recommendations. “Our next steps are doing the advocacy work with the FAA,” she said.

In its January 26 fact sheet, “EMS Helicopter Safety,” the FAA supported the voluntary implementation of TAWS. The agency said it did consider including rotorcraft in its 2002 rule requiring the installation of TAWS devices in all U.S.-registered turbine-powered airplanes with six or more passenger seats. However, the FAA concluded that “there are a number of issues unique to VFR helicopter operations that must be resolved before the FAA considers mandating the use of TAWS in this area,” including the possibility that TAWS, when installed in helicopters operating at low altitudes, could generate false alerts or “nuisance” warnings that could lead pilots to ignore real danger.

Steven Kilbourne, senior test pilot for Honeywell Aerospace, has been working specifically with the company’s Mark XXI and Mark XXII enhanced ground proximity warning system (EGPWS) products since their debut in the helicopter market in 2001. “If you took a purely fixed-wing system and put it in a helicopter, you’d be very unhappy,” he said, noting that Honeywell’s helo EGPWS products are delivered as standard equipment on the Sikorsky S-76 and S-92 as well as the AgustaWestland AW139.

Kilbourne said that about 500 of the Honeywell EGPWS units are currently in service in helicopters, primarily with corporate flight departments and oil rig operators. He said pilots can select from three different levels of sensitivity depending on their particular mission to reduce the incidence of “nuisance” warnings.

However, some EMS operators are reluctant to adopt TAWS because of the potential of such nuisance warnings. “At altitudes that helicopters fly at, you would constantly be warned of rising terrain,” said William Butts, director of operations for Intermountain Life Flight of Salt Lake City, which was involved in one of the fatal accidents highlighted in the NTSB report. “It’s something that is our goal for this year, to look at those [systems] and see what the cost would be.”

While some operators interviewed for this article said that the cost of a TAWS system might be prohibitive, Kilbourne said the Mark XXI can be installed for a little more than $15,000–less than replacing a seat on some helicopters, he said. The Mark XXII costs about $43,400 plus installation. Both models plug into a variety of cockpit displays and weigh only a few pounds, he said, but the XXII offers additional features including pitch and roll information.

Chelton Flight Systems also offers a helicopter TAWS product bundled with its FlightLogic synthetic vision EFIS. No one from the company could be reached yesterday for pricing information or further comment.

At the request of the NTSB, Honeywell Aerospace produced a simulation using its EGPWS to determine whether the August 2004 crash of a Bell 407 in Battle Mountain, Nev., could have been prevented if it had been equipped with TAWS. The NTSB concluded from the demonstration that a “Caution Terrain” aural alert would have been issued 35 seconds before the impact, and a “Warning Terrain” aural alert would have been given 21 seconds before and continued all the way until impact.

In January 2003, an Agusta A109-K2 owned and operated by Intermountain Life Flight crashed while attempting to maneuver in dense fog, killing the pilot and a paramedic and seriously injuring a nurse onboard.

“This accident happened to us and we took it very seriously, and we recognized that we needed to change some of the things that we were doing,” Butts told HAI Convention News. He said that over the last year the company has implemented an instrument currency training program for its helicopter pilots, as well as a risk assessment matrix that each pilot must complete before deciding whether to accept a flight.

Butts said the company has no plans to install TAWS in its two IFR-certified Agusta A109-K2s and two Bell 407s, though its two King Airs are already outfitted with TAWS. The company puts about 1,500 hours a year on its helicopters and is considering replacing at least two of them within the next five years, which could affect its TAWS purchase decision. He said the company’s 14 pilots use night vision goggles on about 80 percent of all night flights.

“The main problem we see with the NTSB report is that it was taken in isolation, focusing on a few accidents without looking at the whole system,” said Tom Judge, executive director of LifeFlight of Maine and past president of the Association of Air Medical Services. “In our move to increase safety we could potentially lose thousands of lives per year especially in rural America. We would decrease the access to care, and thousands of people would die because they couldn’t get to the hospital.”

Judge told HAI Convention News that in developing its recommendations the NTSB “misunderstood” many aspects of EMS operations, and incorrectly concluded that TAWS would increase safety more than other measures, including increasing the number of automated weather reporting stations.