The Sept. 27 fatal crash of a Maryland State Police helicopter performing an emergency medical services (EMS) mission in suburban Washington has yet again put air ambulance choppers in the spotlight as regards air safety.
The nearly 20-year-old Eurocopter Dauphin had picked up two automobile accident victims and was attempting to land in foggy weather when it crashed, killing the pilot, a paramedic, a volunteer emergency worker and one of the two car crash victims onboard.
The crash was one of eight fatal EMS helicopter crashes in the U.S. in the past 12 months, resulting in 31 fatalities. National Transportation Safety Board (NTSB) member Debbie Hersman, who led the Safety Board’s team of investigators at the crash site said “We are very concerned about the safety of this part of the industry. If it’s not safe, you shouldn’t go.”
So far in calendar year 2008, 24 people have died on medical chopper flights, the most deaths recorded in a year previously was 18 in 2004. The six fatal crashes in 2008 to date equal the highest recorded in any previous calendar year.
In 2006, the NTSB issued a special report on air ambulance crashes that included recommendations, many of which the FAA has yet to implement.
The Safety Board called on the FAA to impose stricter requirements on all emergency medical services flights.
The NTSB undertook the special report after investigating 55 EMS accidents in the three-year span between January 2002 and January 2005 that resulted in 54 fatalities and 18 serious injuries. Although the number of flight hours flown by EMS helicopter operations has increased from about 162,000 in 1991 to an estimated 300,000 in 2005, the average accident rate has also increased from 3.53 accidents per 100,000 flight hours between 1992 and 2001 to 4.56 accidents per 100,000 flight hours between 1997 and 2001.
“The very essence of the EMS mission is saving lives. Operating an EMS flight in an unsafe environment just makes no sense,” commented NTSB Acting Chairman Mark Rosenker.
The Safety Board report identified the following recurring safety issues:
- Less stringent requirements for EMS operations conducted without patients on board.
- A lack of aviation flight risk evaluation programs for EMS operations.
- A lack of consistent, comprehensive flight dispatch procedures for EMS operations and,
- No requirements to use technologies such as terrain awareness and warning systems (TAWS) to enhance EMS flight safety.
The Board recommended that the FAA require the installation of terrain warning systems on all EMS aircraft. The report reviewed several technologies that can assist in flight operations – terrain awareness warning systems (TAWS) and night vision imaging systems (NVIS). Controlled flight into terrain is a common factor in helicopter EMS accidents that could be alleviated by the use of TAWS. The investigations of 17 of the 55 accidents determined that TAWS might have helped pilots avoid terrain.
In addition to TAWS, the Safety Board found that some EMS operators were using NVIS to enhance a pilot’s ability to avoid terrain. The Board determined that if used properly, NVIS could help EMS pilots identify and avoid hazards during nighttime operations. However, because NVIS are not feasible in some situations such as populated areas with ambient light or numerous streetlights, the NTSB did not make a recommendation on this subject.
For its part, the FAA says “Helicopter Emergency Medical Service (HEMS) operations are unique due to the emergency nature of the mission. In August 2004, the FAA initiated a new government and industry partnership to improve the safety culture at HEMS operators and recommend short-and long-term strategies for reducing accidents.
“While the FAA has not ruled out proposing new or changing existing rules, the agency has prompted significant short-term safety gains that do not require rulemaking,” the FAA added.
The FAA says it has “a solid record of facilitating safety improvements and new technologies for EMS helicopters, including certification of Night Vision Goggles (NVGs).”
The FAA supports the voluntary implementation of TAWS and did consider the possibility of including rotorcraft in the TAWS rulemaking process. Through this process, 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, such as modification of the standards used for these systems.
For example, helicopters typically operate at lower altitudes so TAWS could potentially generate false alerts and “nuisance” warnings that could negatively impact the crew’s response to a valid alert. TAWS application to HEMS would require study of TAWS interoperability within the lower altitude HEMS environment, and possibly a modification of TAWS system standards.
At the FAA’s request, RTCA established a Special Committee (SC-212) to develop H-TAWS standards for use in future FAA rulemaking. The final report was delivered to RTCA in March 2008. Those standards are being reviewed by the FAA’s Aircraft Certification Service for the development of an HTAWS technical standards order.