Fatal accidents involving helicopter emergency medical services (HEMS) flights in the United States have declined dramatically since 2008 — the deadliest year on record, when nine fatal crashes claimed 29 lives.
The next nine fatal accidents were spread over a period of more than four years — two in 2009, four in 2010, one each in 2011 and 2012, and one in the early days of 2013. Together, those crashes killed 28 people (see Table 1, p. 24).
Industry representatives credit the decline to HEMS operators’ voluntary adoption — in advance of anticipated new regulatory requirements from the U.S. Federal Aviation Administration (FAA) — of a range of safety initiatives, including safety management systems (SMS), flight operational quality assurance (FOQA), improved education and training, helicopter terrain awareness and warning systems (HTAWS) and, perhaps most importantly, night vision goggles (NVGs).
“There’s no other single advancement that’s had such an immediate impact,” said Christopher Eastlee, president of the Air Medical Operators Association (AMOA). “We don’t run into stuff we don’t see anymore.”
NVGs are in use today by at least 90 percent of U.S. HEMS operators, up from only 2 to 5 percent in 2006, Eastlee said. Among those using NVGs are all major operators, each of which has installed the systems in all, or nearly all, of its helicopters.
AMOA, established in 2008 to respond to the surge in fatal HEMS crashes, represents operators of more than 730 of the country’s approximately 800 EMS aircraft, including all major operators.
Industry representatives, including AMOA and the Association of Air Medical Services (AAMS), noted, however, that appropriate training in the use of NVGs is essential if the devices are to be effective in helping to avoid collisions with terrain and obstacles.
Unfamiliarity with Hazards
Training also was emphasized in an accident report by the U.S. National Transportation Safety Board (NTSB), which cited “the pilot’s unfamiliarity with the hazards of a low-contrast area while using night vision goggles” as a contributing factor in the Feb. 5, 2010, crash of a Eurocopter AS350 in El Paso, Texas.
While maneuvering to land in the desert for a simulated patient pick-up, the helicopter orbited the landing site, using a non-NVG-compatible spotlight, then made a wide orbit, banked 45 degrees, “entered a steep nose-down attitude and impacted the ground,” the NTSB report said. The probable cause was the pilot’s loss of situational awareness, which resulted in controlled flight into terrain.
The 17,600-hour pilot and two paramedics — the only people in the helicopter — were killed, and the NTSB said the helicopter was substantially damaged in the crash, which occurred during the pilot’s second flight with the company, and his first “uninstructed … NVG flight since his recent company training,” which he had completed Jan. 29, after 7.5 hours using NVGs.1
The accident occurred in a remote area with no light from the moon and little cultural lighting (that is, man-made lighting, such as the lights of a town), and the pilot’s NVG training “had all been conducted on nights with high moon illumination and in populated areas with high amounts of cultural lighting and did not prepare the pilot for flight in the conditions encountered on the night of the accident,” the report said. “The low visual contrast conditions, combined with the narrow field of view of the NVGs, reduced the pilot’s ability to maintain situational awareness. The lack of attempted recovery prior to ground impact suggests that the pilot did not recognize the helicopter’s descent rate and bank angle.”
NVGs are known for their “tendency to distort depth perception and distance estimation, with the quality of depth perception being dependent on ambient light, terrain surface conditions, the ability of the NVG device and the pilot’s experience in flying in those conditions,” the report added.
Vigilance and Caution
Bill Winn, general manager of the National EMS Pilots Association (NEMSPA), said that, in addition to NVGs, increased vigilance and caution by pilots has helped reduce the number of accidents.
The surge in crashes in 2008 led to heightened management scrutiny and actions to “promote conservative decision making on the part of their pilots,” said Winn, a pilot for Intermountain Life Flight in Salt Lake City.
In addition, medical crewmembers have been encouraged to take a more active role in questioning pilots about the continuing safety of flight, and the en route decision point (EDP) process promoted by NEMSPA has emphasized that pilots should never deviate from safe airspeed and altitude, Winn said. EDP guidelines specify that airspeed should never be less than 30 kt below normal cruise airspeed and altitude should never be less than the FAA’s specified minimum en route altitude for uncontrolled airspace — no lower than 300 ft during the day (or 500 ft at night) above the highest obstacle along the route of flight.
Blair Marie Beggan, director of communications for AAMS, which represents providers of air and ground medical transport systems, said the HEMS industry has worked hard “to achieve a steadily declining accident rate, through a multi-layered approach.”
Enhanced education and training are essential not only in the use of NVGs but also in recurrent training in simulators and aircraft, Beggan and Eastlee agreed.
“While there are other safety objectives … none of them can provide a level of risk mitigation equal to that of a frequent training program that makes use of available flight training devices, simulators or operational aircraft with instructors providing simulated scenarios including inadvertent [entry into] instrument meteorological conditions (IMC) on at least a semiannual recurrent basis,” Eastlee said.
AMOA member operators also provide recurrent air medical resource management training for medical crewmembers “to ensure a positive crew resource environment,” he said.
Continuing education and training, in combination with SMS, are intended to “combat complacency and increase personal accountability” and to improve the safety culture throughout the HEMS industry, Beggan said.
Nearly all AMOA members have implemented SMS, the organization said, adding that SMS is an essential, collective approach that combines all safety objectives into one system.
Data collection and analysis is a key ingredient in safety oversight, another element of SMS, and industry representatives have advocated one form of oversight through FOQA or similar flight data monitoring programs.
A number of HEMS operators have begun using FOQA, and “some individual operators have learned quite a bit from their own systems,” Eastlee said. Eventually, those using FOQA hope to coordinate their efforts to improve prospects for inter-company data sharing and analysis, he said.
Winn said that, in addition to helping identify and correct procedural errors, FOQA also has served as a deterrent for pilots tempted to depart from standard operating procedures.
“Any pilot who knows big brother is there watching and who might have been tempted to cowboy the aircraft or push weather won’t do it,” he said.
Eastlee said that, in recent years, the industry also has emphasized various other forms of oversight, through enhanced regulations and procedures, management monitoring of those enhancements, and guidance on risk assessment and mitigation. Another element of oversight comes in the form of operational control centers, which the FAA said already were in place at nearly 90 percent of HEMS operations in 2009. The FAA has proposed, in rules changes expected to be made final in late March, that control centers be required for any operator with 10 or more helicopters.
The industry also is “fully supportive of heightened FAA regulations for helicopter air medical services,” Beggan said.
Those regulatory changes, which were first proposed in 2010, are expected to be issued in final form in late March.
The 2010 proposals call for all HEMS flights with medical personnel aboard to be conducted under U.S. Federal Aviation Regulations (FARs) Part 135, which governs commuter and on-demand operations and imposes stricter limits for weather minimums and flight crew duty and flight time limitations and rest requirements. Under current requirements, those flights may be conducted under the less stringent rules of FARs Part 91.
Despite industry support for NVGs, the proposed changes would not require their use; the FAA said in introducing the proposed rules changes that more research was needed on their effectiveness before such a requirement would be considered. Instead, the proposed changes called for installation of HTAWS equipment within three years after issuance of a final rule.
At the time, many industry groups asked the FAA to consider allowing operators to install HTAWS or NVGs or both, arguing that each technology has unique safety benefits.
In addition to the large numbers of HEMS aircraft equipped with NVGs, about two-thirds now have HTAWS, Eastlee said.
In its proposed rules changes, the FAA had asked for comments on a possible future requirement for the installation of lightweight aircraft recording systems in EMS helicopters. The devices would not only enable participation in FOQA programs but also allow the NTSB to collect data in case of an accident.
The NTSB has for several years urged the FAA to require the collection and analysis of safety data by these operators through flight data monitoring programs. In a package of HEMS safety recommendations issued in 2009, the NTSB noted the development of flight data recording devices that were low cost, lightweight and compact enough to enable even small operators to implement flight data monitoring.
“Such data would be particularly useful in evaluating pilot performance in daily operations according to specific parametric operational standards, such as altitude, bank angle, pitch attitude and airspeed limitations,” the NTSB said. “Frequent downloading and analysis of these data can aid operators in implementing an SMS by identifying exceedances that occur during operations in order to implement corrective actions. In addition, periodic review of flight data from HEMS flights would provide information on aircraft proximity to terrain and weather that could assist in evaluating pilot performance to determine if pilots are conducting HEMS flights in accordance with company operating practices.”
In issuing the recommendations, the NTSB said a flight data monitoring program might have helped prevent the June 29, 2008, collision of two Bell 407 EMS helicopters in Flagstaff, Arizona (ASW, 7/09, p. 32). All seven occupants were killed in the crash, which destroyed both helicopters. The NTSB said the probable cause of the accident was each pilot’s failure to see and avoid the other helicopter as both aircraft approached the Flagstaff Medical Center helipad.
“The systematic monitoring of data from HEMS flights could provide operators with objective information regarding the manner in which their pilots conduct HEMS flights and … a periodic review of such information, along with other available information such as pilot reports and medical crew feedback, could assist operators in detecting and correcting unsafe deviations from company operating practices,” the NTSB said.
Among the areas in need of more attention is the infrastructure in place for the low-level altitudes where EMS helicopters operate, Beggan said.
“The FAA has invested billions of dollars over the last several decades into a strong infrastructure for commercial air carriers,” she said. “By comparison, HEMS providers operate at low-level altitudes for which there is little infrastructure in place, including a scarcity of accurate weather reporting and … in some areas, no radar-based air traffic control.”
A recurring theme in fatal HEMS crashes has been bad weather, and especially inadvertent entry into IMC, which often is cited in HEMS accident reports.
For example, an Aug. 31, 2010, crash in Walnut Grove, Arkansas, that killed the pilot, flight nurse and flight paramedic, was attributed by the NTSB to the pilot’s loss of control of the helicopter following several minutes of multiple course reversals considered “consistent with spatial disorientation and subsequent loss of control due to an inadvertent encounter with [IMC].”2
In some cases, the absence of accurate weather reporting has factored in a crash, Beggan said.
Eastlee agreed that many of the difficulties that have plagued HEMS operations are associated with the low-altitude operations that are a necessary part of their mission.
“Large airplanes can fly over bad weather, but … everything for us involves flying through it,” he said.
Overall, EMS helicopters transport patients on 400,000 flights every year, and another 400,000 operations are conducted without patients aboard.
“That’s a tremendous volume of very successful flying,” Eastlee said, adding, however, that the accidents of recent months demonstrate that some ongoing safety enhancements must be strengthened.
- NTSB. Accident Report no. CEN10FA113. Feb. 5, 2010.
- NTSB. Accident Report no. CEN10FA509. Aug. 31, 2010.