The Safety of Air Ambulances
Released: 2006-05-23T00:00:00

An Analysis of Air Ambulance Safety Data

A recent increase in the number of crashes involving air ambulances has raised concernsamong aviation safety experts. According to a National Transportation Safety Board (NTSB) specialstudy focusing on aviation emergency medical operations released in January 2006, 55 crashesinvolving air ambulances occurred in the United States between January 2002 and January2005. (1) The NTSB notedthat this number of crashes has not been seen since the 1980s. Given that the current air ambulancefleet is estimated to consist of about 750 helicopters and 150 fixed wing aircraft, (2) each year over the past threeyears, about one in every 50 helicopter air ambulances has been involved in a crash. An article in USA Today offered the following stark analogy: "If commercial airlines lost the same proportion oflarge passenger jets as air ambulance companies lost helicopters, 90 airliners would crash eachyear." (3)

Because there is no centralized database of flight records for the air ambulance industry, noone knows for sure if safety is eroding or if this increase in accidents can be explained by the largegrowth in the use of helicopters and airplanes for medical evacuation and patient transport. TheNTSB notes that while industry estimates suggest that the number of hours flown by air ambulanceshas increased by about 85% over the past 15 years, the estimated accident rate for helicopter airambulances has also risen from 3.52 accidents per 100,000 flight hours between 1992 and 2001 to4.56 accidents per 100,000 flight hours between 1997 and 2001. (4) The NTSB, however, did notprovide its own estimates of accident rates or more recent figures on the annual accident rates forair ambulances.

Available accident statistics and analyses reviewed by CRS have focused on helicopter airambulance operations, which make up more than 80% of the air ambulance fleet. Consequently thisreport concentrates on safety data and finding related to helicopter air ambulances, although manyof the issues and observations may be more broadly applicable to both helicopter and fixed-wingair ambulances.

While much of the flight hour data to substantiate accident rate statistics for air ambulanceoperations remains sketchy, CRS analyzed helicopter air ambulance safety data and computedaccident rates using accidents between 1991 and 2004 identified in the 2006 NTSB special studyreport, and accident data and industry estimates of hours flown by helicopter air ambulance operatorscited in a comprehensive safety review and risk analysis of air ambulance accidents published by theAir Medical Physician Association (AMPA). (5) This analysis estimated that the overall accident rate among airambulance operators from 1991 to 2004 to be 3.50 accidents per 100,000 flight hours and the fatalaccident rate to be 1.13 accidents per 100,000 flight hours. Looking only at the data since 1998when a notable spike in accidents was first observed, the estimated overall accident rate rose to anaverage of 4.75 accidents per 100,000 flight hours and the estimated fatal accident rate increasedslightly to 1.25 accidents per 100,000 flight hours. Three-year moving averages of the estimatedaccident rate were computed across the 14 year period based on available flight time estimates andare shown in Figure 1 . (6) The trend in the three-year moving average accident rates suggests a steady increase in the accidentrate from 1991 through 2003, with a slight reversal of this trend in 2004. The data also show a slightrise in the fatal accident rate over the past five years. While these data demonstrate an increase inhelicopter air ambulance accident rates, particularly since 1998, they cannot be regarded asconclusive because of the lack of reliable data on the overall number of hours flown. However, thesedata, based on best available information, strongly suggest that there is cause for concern regardingthe safety trend for air ambulance operations.

Figure 1. Three-Year Moving Average of Estimated Overall and Fatal AccidentRates for Helicopter Air Ambulance Operations

Sources

Special Investigation Reporton Emergency Medical Service Operations.

A Safety Review and Risk Assessment in Air MedicalTransport,

Note

There are two key concerns regarding these accident rate estimates. First, the trend showsa steady increase in estimated accident rates over the past 14 years, with a more marked increasedsince 1998. Second, these estimated accident rates are notably higher than many other commercialaviation sectors. In particular, over the same period (from 1991-2005), non-scheduled air taxioperators, which fly under the same rules as air ambulance operators carrying patients, experiencedan overall accident rate of 2.52 accidents per 100,000 flight hours and a fatal accident rate of 0.67fatal accidents per 100,000 flight hours. (7) While air ambulance operations, particularly helicopter airambulance operations, by their nature may arguably be inherently more risky than other commercialaviation operations, the relatively higher estimated accident rates coupled with the observed trendof increasing accidents and estimated accident rates suggests that the causes of these accidents andpossible options to reduce these numbers is an appropriate topic for policy analysis.

When the NTSB previously examined commercial emergency medical service helicopteroperations in 1988, it estimated that the overall accident rate between 1980 and 1985 was 12.34 per100,000 flight hours, almost twice the estimated accident rate experienced by non-scheduledhelicopter air taxis during that period. (8) Moreover, the fatal accident rate of 5.40 per 100,000 flight hourfor helicopter air ambulances between 1980 and 1985 was estimated to be about 3 Â½ times the fatalaccident rate for non-scheduled helicopter air taxis and all turbine-powered helicopters. (9) While more recent accidentrate estimates among helicopter air ambulance operators have been climbing steadily, they stillappear to be much lower than estimates for the early 1980s. However, the lower observed accidentrates in the early 1990s suggest that safety improvements can be made in air ambulance operationsto reduce the overall and fatal accident rates compared to recently observed levels. Specifically,between 1991 and 1995, the helicopter air ambulance industry had an estimated 1.81 accidents and0.91 fatal accidents for every 100,000 flight hours, accident rates that closely resemble those of othercommercial aviation operations such as the previously cited statistics for non-scheduled air taxioperators. Arguably, based on these data, the helicopter air ambulance industry has alreadydemonstrated that it can achieve a better safety record than what it has experienced since 1998.

Although air ambulance operations can be inherently riskier than other aviation operationsbecause the environment in which they operate is more dynamic and unpredictable, some expertshave raised concerns that the air ambulance industry and the FAA are simply accepting a higheraccident rate than other areas of the aviation industry rather than taking steps to reduce the numberof accidents. (10) Whilethe FAA and the air ambulance industry have acknowledged that ongoing safety concerns exist,critics argue that their actions to date -- largely consisting of advisory materials andrecommendations requiring only voluntary compliance by operators -- are inadequate. To furtherassess the root causes of air ambulance accidents and assess possible policy changes to improvesafety in the air ambulance industry, it may be beneficial to examine the operational role of airambulances as well as the current state of the air ambulance industry and management practices inthe air ambulance industry.

The Role of Air Ambulances

When most people think of an air ambulance operation they are likely to first considerhelicopter transports of trauma patients, such as car accident victims. This has historically been thepredominant form of air ambulance service since its beginnings in the early 1970s. Large scale useof air evacuation of wounded troops was demonstrated to be an effective means of reducing combatmortality both in the Korean and Vietnam conflicts. Based on this experience, civilian air ambulanceuse in the United States began on a small scale starting in the early 1970s and has grown significantlysince. Although some studies have found little or no benefit from helicopter evacuations of civiliantrauma patients, numerous studies point to improved chances for recovery and significant reductionsin mortality rates when air ambulance services are made available to trauma patients. (11) Medical theory andpractice holds that providing critically injured patients with surgical intervention within the first hourafter injury -- the so-called "Golden Hour" -- can significantly improve the chances for survival andrecovery. (12) In practice,air ambulances, particularly helicopters, can play an important role in this intervention by providingrapid patient transport to trauma centers where they can be effectively treated, and in some casesproviding advanced life support capabilities en route. The availability of this service provides animportant role, especially in rural communities that lack readily accessible advanced care facilitiesand medical specialists.

More recently, there has been increased utilization of air ambulances, both helicopters andairplanes, for both on-scene response and inter-facility transport of critical cardiac patients and strokevictims. Both helicopters and fixed-wing aircraft are also utilized for other inter-facility transfersto give patients access to specialty care facilities and medical specialists. While the on-sceneresponse of a helicopter at a traffic accident is probably what first comes to mind when the term airambulance is used, today about 54% of all air medical transports are from hospital to hospital, whileon-scene responses make up 33%. The remaining 13% include organ and medical supply andspeciality medical team transports. (13) Air ambulances can also play an important role in emergencyevacuation of critical care patients and transport of medical supplies and staff to disaster areas, aswas demonstrated in the aftermaths of Hurricanes Katrina and Rita in 2005. (14)

While some critics assert that air ambulance transports are being over utilized, (15) there is generallywidespread acceptance of the benefit provided by both the general public and the medicalcommunity. The air ambulance community acknowledges that utilization of air ambulances in somecases may, in retrospect, prove to have been unnecessary. This, they argue, is to be expected if themedical community is to assure that the maximum number of patients who could potentially benefitfrom air ambulance services are provided with this service. Over the past 15 years, guidelines forair medical dispatch have been refined by the air ambulance community and emergency roomphysicians. These various guidelines set forth circumstance-specific and patient-specific criteria fordecision makers assessing whether to dispatch a flight as well as for analysts reviewing and modelingutilization and refining resource allocation across a particular geographic area. (16) The industry also arguesthat while air ambulance services are comparatively costly when examined on a single-case basis,appropriately used air medical transport is cost-effective on a system-wide basis, largely due to moreefficient coverage of large geographic areas, reduced patient transport times, and more rapidintervention that can reduce overall patient care costs. (17) In general, air ambulance services have garnered widecommunity support and endorsement from the medical community as being a beneficial andcost-effective service for improving access to critical health care and increasing the chances ofsurvival and recovery for trauma victims and critically ill patients, particularly in areas where accessto specialized health care is limited. Consequently, air ambulance utilization is likely to continue itssteady growth throughout the United States, particularly in rural areas. This expectation of continuedgrowth for the industry draws particular attention to the ongoing safety concerns, because continuedgrowth without any improvement to safety could trigger widespread public concern over the safetyof these operations which has already been evidenced to some degree based on recent mediacoverage of the issue. (18)

State of the Air Ambulance Industry

The civilian air ambulance industry can trace its origins back to the early 1970s with thecreation of the Maryland State Police aviation program in 1970 and the first hospital-based medicalhelicopter service at St. Anthony's Hospital in Denver, Colorado in 1972. Prior to then, policedepartments in the 1960s and early 1970s had used helicopters on occasion to transport criticalpatients, but provided very limited en route patient care. The air ambulance industry gradually grewduring the 1970s and by 1980 included 32 helicopter emergency services flying 39 helicopters. During the 1980s, the industry grew fivefold and by 1990 included 174 helicopter emergencyservices and 231 helicopters. The industry experienced continued growth in the 1990s expandingto 231 helicopter emergency services flying 400 helicopters by 2000. (19)

A variety of factors, including increases in Medicare reimbursement rates for air ambulanceservices and recent declines in available emergency medical and advanced patient care services inrural areas, have resulted in a significant growth in the air ambulance industry over the past fiveyears. In 2005, there were 272 helicopter emergency services flying 753 helicopters in the UnitedStates, roughly an 88% increase in the number of helicopter air ambulances compared to the size ofthe industry in 2000. In 2005, there were also an estimated 150 fixed-wing airplanes dedicated toair ambulance operations used mostly for inter-hospital transfers. (20) Based on industry flighthour estimates, growth in the use of air ambulances has been increasing at a rate of about 4.5% peryear over the past 15 years, and most observers believe that this steady growth in both the size of thededicated air ambulance fleet in the United States and the utilization of air ambulances will continueover the next several years.

While some states and municipalities and other public agencies operate air ambulances aspublic aircraft, most air ambulance services are privately owned and operated, either directly by ahospital or hospital consortium or by private aviation medical service providers. The Maryland StateHighway Patrol has a comprehensive helicopter air ambulance capability that covers the entire state,while the California Highway Patrol and the Virginia and Delaware State Police provide airambulance services in portions of those states. Several county police forces and emergency medicalunits throughout the United States also perform air ambulance missions. Also, federally operatedaircraft provided by the U.S. Coast Guard in Alaska and the U.S. Army in Hawaii conduct civilianair ambulance operations. CRS estimates that federal, state, and local government-operated aircraftcurrently account for about 10% of air ambulance operations in the United States. However, privateoperators make up the large majority of air ambulance services across the United States. (21) Unlike aircraft that areoperated by a state or local agency which are considered public aircraft and therefore not under directFAA oversight, air ambulances operated by private companies are regulated by the FAA, andtherefore have been the focus of safety studies examining safety within the industry and the FAA'sactions to monitor and regulate safety. (22) These private aviation medical providers may operate underdirect contract providing aircraft and flight crews to a specific hospital or hospital consortium, or asis becomingly increasingly more common, may act more as a independent entity with affiliationswith various hospitals over a large geographic region.

In the late 1990s, regulatory changes requiring ambulance services, including air ambulances,to bill patients separately from hospital charges as well as increases in Medicare reimbursement forair ambulance flights in some regions, brought about significant changes to the industry. (23) Most helicopteremergency medical services in the 1980s and early 1990s were either run directly by hospitals andemergency facilities or, more commonly, operated under hospital-managed contracts with aviationcompanies that provided the helicopters and pilots. (24) Today, many of these services are now operated by stand-alone,private entities with hospital affiliations, and in many locations, there is direct competition betweenair ambulance service providers within a region.

While some states and local governments provide air ambulance services as a public goodor quasi-public good, privately-run operations are far more common. The Maryland State PoliceAviation Command, as an example of a state-run system, derives about two-thirds of its fundingfrom automobile registration fees and the remainder from general state treasury funding for the statepolice. Patients are consequently not required to pay for transport and medical costs provided by thisservice. In the privately-operated air ambulance model, by contrast, patients or their insurers aredirectly billed for charges incurred for air ambulance transport. Although privately-operated airambulance services provide an important function in the communities they serve, critics argue thatthe financial pressures associated with operating these services as well as insufficient regulatoryrequirements and oversight may be significant factors that could negatively affect flight safety acrossthe industry.

Although competition and associated pressures to conduct missions was already present whenthe NTSB examined air ambulance helicopter safety in 1988, it was generally concluded thathelicopter patient transport at that time was not profitable on the basis of transportation alone. Infact, a 1986 survey cited by the NTSB found that patients were, on average, only charged for about75% of the direct cost of air ambulance transport. (25) Hospitals made up for these losses through charges for otheradvanced care services provided at the hospital. Thus, the competition that existed in the 1980s waslargely between hospitals. From a business perspective, air ambulances, at that time, were largelyseen as a marketing tool to increase public recognition of the hospital within the community andattract patients. In the current environment, however, the competition appears to be more directlyrelated to the flight mission as the business model for most private-sector air ambulance services hasbeen shifting toward stand-alone operators that market their services to local hospitals, emergencyofficials, and even to the general public. (26) One example of marketing to the general public is the sales ofyearly "memberships" that will cover any gaps not paid by insurance for air ambulancetransports. (27) Variouscompetitive pressures, including direct competition among services and the desire to satisfy hospitaland emergency medical service administrators that oversee air ambulance contracts, can potentiallyaffect flight safety if they factor into decisions regarding whether to accept or continue a flightmission. Operating air ambulances as private businesses may also create financial pressures thatcould lead some operators to forego safety improvements or enhancements that are not specificallyrequired in order to keep operational costs at a minimum. These various operational pressures thatexist in the air ambulance industry and their potential impact on safety will be considered in greaterdetail along with other possible causal and contributing factors in air ambulance crashes.

Causes of Air Ambulance Crashes

The large majority of air ambulance accidents occur due to a chain of circumstancesinvolving pilot decision-making and performance and flight conditions such as weather and terrain. In particular, darkness, reduced visibility, and rising terrain present significant challenges and risksto air ambulance operators -- particularly helicopter operators -- and are often cited as causal factorsin accidents. Pilot knowledge or "situation awareness" regarding weather conditions and terrain has also been found to be a significant factor in a large number of air ambulance accidents.

CRS analyzed a database of 120 helicopter air ambulance accidents compiled by theHelicopter Association International that occurred between 1991 and 2004. Causal factors werecategorized based on brief descriptions of the accident circumstances and weather conditionsprovided in this database. The results of this analysis are shown in Figure 2 .

Figure 2. Factors in Helicopter Air Ambulance Accidents (1991 -2004)

Source

Air Medical Service Accidents, 1991 thru 1994,

Note

Interaction Between Pilots and Flight Conditions. The interplay between the pilot or flight crew (the operator) and environmental factors such asweather and terrain played a part in roughly 80% of the accidents examined. This finding closelymatches other analyses examining the causes of air ambulance crashes. (28) One of the most commoncausal factors in these accidents, cited in 27.5% of the crashes, was what aviation safety experts referto as controlled flight into terrain (CFIT), a broad category that generally involves a loss of situationawareness regarding surrounding terrain, often in poor visibility or at night. The other most citedfactor, also identified in 27.5% of the accidents, was aeronautical decision making and situationawareness (ADM/SA), which refers to a pilot's knowledge of factors affecting the safety of flight andthe ability to evaluate risk based on these factors and make appropriate informed decisions. Anothercontributor to helicopter air ambulance crashes, related to errant pilot decision making, is continuinga flight using outside visual references as is permissible under visual flight rules (VFR) into poorweather and visibility conditions, known to aviators as instrument meteorological conditions (IMC). Continued VFR into IMC, as it is referred to by air safety experts, was cited as a causal factor in 9%of helicopter air ambulance crashes. Other pilot-related factors cited in a number of accidentsincluded loss of aircraft control, pilot technique, and visual illusions, all factors that frequently cropup in poor visibility conditions when a pilot loses visual reference to the horizon or the ground belowand is unable to effectively transition to flight solely by reference to cockpit instruments. Theseflight operational factors are a central concern and have been the focus of the NTSB's safetyrecommendations regarding air ambulance operations as well as the efforts of the FAA and the airambulance industry to encourage voluntary implementation of systems safety and risk managementconcepts in air ambulance operations.

Pilot Situation Awareness of Weather Conditions. In its most recent review of air ambulance safety, the NTSB found that situation awareness can oftenbe lacking in air ambulance operations for a variety of reasons, but was chiefly concerned with thelack of formal flight dispatch procedures among operators. Air ambulance pilots lack the benefit ofconsistent, comprehensive flight dispatch procedures and often rely on emergency (911) dispatchers,referred to in the industry as communications specialists, or emergency medical personnel thattypically have no formal training in flight dispatch procedures. In 11 of the 55 accidents reviewedby the NTSB in their 2006 special study, incomplete or missing information regarding weather, routeof flight, and coordination with on-scene rescue personnel factored into the causal chain of theaccident. The NTSB, consequently, recommended that the FAA require air ambulance operators touse formalized dispatch and flight-following procedures that include up-to-date weather informationand assistance in flight risk assessment decisions. (29) In response to this recommendation, policymakers might opt toassess the benefits and costs of implementing formal flight dispatch procedures and specific trainingin these procedures to both flight crews and ground communication specialists in the emergencymedical field that coordinate and dispatch air ambulance missions.

Mission Pressures. Aviation safety experts havealso pointed to pressures to complete the mission as factors that can lead to poor judgment amongair ambulance pilots and contribute to accidents. In 1988, the NTSB found that mission pressurescould be exacerbated by a lack of on-site supervision among operators, particularly those operatorsthat service a broad geographic area. In many of these instances, the NTSB found that a pilot'simmediate supervisor was not located at the pilot's base station or hospital, and in some cases, waslocated in a distant city. The NTSB concluded that isolation from management forces pilots to lookfor structure and guidance from other sources, particularly hospital emergency service administratorsand personnel. This arrangement can result in pilots placing greater importance on the medicalmission and potentially may compromise sound judgment with regard to flight safety. The NTSBnoted that:

[h]ospital management, the EMS medical personnel,and the dispatchers can all intentionally or unintentionally put pressure on the pilots to take a flightin marginal weather conditions. The reasons for these pressures include misunderstanding or lackof understanding of weather-related considerations, genuine zeal to get a job done, or evencompetition between EMS programs. (30)

The NTSB also found that, besides the pressures to complete missions based on medical needinfluencing flight safety considerations, the relationship between air ambulance operators andhospitals can play a role in decisions regarding whether to accept or continue a mission. Pilots mayfeel pressured to accept or continue missions in marginal weather conditions in order to satisfyhospital administrators and maintain good business relations with them. In privately-operated airambulance services, the hospital is, in essence, a customer of the air ambulance service, and pilotsmay feel compelled to satisfy their customer by accepting and completing a maximum number ofmissions. These pressures may be even greater at hospitals and in regions where there is directcompetition among air ambulance providers.

A survey of helicopter air ambulance pilots found that while pressure to accept or continuemissions is a significant concern, pilots more frequently cited pressure to speed up response time asthe most significant pressure factor affecting mission safety. Internal and external pressures to speedup response time could cause pilots to miss important risk factors and fail to obtain a fullunderstanding of the weather, route of flight, obstacles and obstructions en route, and other keypieces of information during the flight preparation process.

Policymakers may consider options to require specific training and implementation of riskmanagement techniques for air ambulance operators dealing with the specific operationalenvironment and operational pressures of the air ambulance industry. While the FAA has provideda variety of training materials and resources on aeronautical decision making that are both generalin nature as well as specific to unique considerations for helicopter and air ambulance operations,decision making and various external pressures that may effect pilot judgment on air ambulancemissions is often not covered in depth during initial and recurrent pilot training. Therefore,policymakers may consider more formal training and testing of aeronautical decision makingconcepts specific to air ambulance operations as a possible option for mitigating accidents relatedto poor judgment and decision making errors.

Besides training in aeronautical decision making, formal techniques for evaluating theoperational risks associated with each flight assignment may benefit pilots in the decision makingprocess. The FAA has recommended that helicopter air ambulance operators implement formaloperational risk assessment programs to evaluate flight safety and risk for every mission. (31) The recommendedpractices include empowering pilots to be the final decision authority in accepting or declining amission assignment; incorporating formal risk assessment tools for gauging the level of risk on aspecific mission; and carrying out a risk mitigation plan to reduce risks to acceptable levels whenfeasible. Factors considered in formal pre-flight risk assessments include weather and visibilityconditions; terrain and route of flight; pilot qualifications, experience ,and fitness for duty; anymaintenance issues such as inoperative equipment; and aircraft performance capabilities andlimitations. Examples of techniques for mitigating risk factors may include more stringent weatherminimums for less experienced pilots; more stringent weather minimums when certain equipmentis inoperative or otherwise unavailable; and the use of special equipment to improve a pilot'ssituation awareness and ability to see and avoid terrain and obstructions at night and in poorvisibility. While the FAA has issued voluntary guidance to helicopter air ambulance operators setup these risk management programs, the NTSB has recommended that these flight risk evaluationprograms be made mandatory for all air ambulance operators, and require formal training in the riskevaluation process for all employees directly involved in flight missions, not just pilots. (32)

Conditions in the Flight Environment. Withregard to environmental conditions, night, weather, obstructions (such as power-lines) andmountainous terrain, or some combination of these factors was found to have played a role in a largenumber of the helicopter air ambulance accidents reviewed by CRS. Presently, air ambulanceoperators, for the most part, are not required to equip their aircraft with instruments that couldimprove situation awareness regarding height above terrain and potential terrain collisions, nor arethey required to utilize any special equipment that could enhance visibility at night and in poorweather conditions. While the FAA, in its guidance to air ambulance operators and inspectors whooversee these operations issued in January, 2006, identified this equipment as a means to avoid lossof control and CFIT accidents, it has not required use of this equipment to date. (33) However, the NTSBissued a recommendation to the FAA, based on its 2006 special study findings, that wouldspecifically require the use of terrain warning systems on air ambulances. (34)

Mechanical Failures and Maintenance RelatedCrashes. In addition to flight operational factors and conditions of flight, asignificant proportion (about 22%) of the helicopter air ambulance accidents examined were foundto be attributable, at least in part, to some type of mechanical failure. This finding roughly matchesthat of an earlier comprehensive study looking specifically at maintenance-related helicopter airambulance accidents over a 24-year period which concluded that 23% of all helicopter air ambulanceaccidents reviewed were maintenance-related. (35) That study found that 50% of helicopter air ambulance crashesattributable to mechanical or maintenance-related causes were engine related, while 24% were dueto failures of the main rotor drive or transmission, 13% were attributed to malfunctions of the tailrotor system, and another 13% were attributed to faulty flight controls. These findings suggest thatmaintenance of air ambulances poses a significant safety risk. However, neither the FAA nor theNTSB has identified maintenance practices among air ambulance aircraft as a specific area forconcern. Consequently, present efforts to prevent air ambulance crashes are focused, instead, on riskfactors associated with flight operations and pilot performance. Available data suggests thatpolicymakers might also choose to consider a more in-depth examination of maintenance practicesin the air ambulance industry to identify ways to reduce maintenance-related accidents.

Options for Improving Safety

Based on available data summarized above suggesting that flight operational factors are thecentral cause of the large majority of air ambulance accidents, options for improving safety havefocused on possible changes to flight operations and practices among air ambulance operators. These various options have been framed in terms of possible alternatives for changing regulatorystandards and oversight of air ambulance operators, incorporating system safety and riskmanagement principles into the decision making processes regarding air ambulance missions,providing additional or supplemental training for flight crews as well as medical crews, andincorporating various technologies to aid pilots and improve safety in low visibility conditions.

Regulatory Standards and Oversight

Media coverage of air ambulance safety has raised concerns over the degree of oversight thatthe FAA has devoted to air ambulance operators, asserting that the FAA has been unable to keeppace with the industry's rapid growth. (36) Those expressing concern believe that the FAA has been lax ininspecting air ambulance operations, particularly for new operators and operational bases, as wellas at remote base stations that are distant from company headquarters. (37) In terms of regulations,critics also contend that the FAA has been slow to take action to better regulate safety among airambulance operators. The NTSB noted that while the FAA has taken a positive step towardimproving air ambulance safety by creating a task force in August 2004 to look into helicopter airambulance accidents, that task force had not yet made any specific recommendations or proposalsfor regulatory change. (38) The FAA has, however, issued special guidance to helicopter air ambulance operators and hasintensified efforts to review these operators' training and procedures.

Conducting Special Emphasis Inspections. In Fall2005, the FAA initiated a special emphasis inspection program targeting helicopter air ambulanceoperators. The inspection program is designed to focus on policies, procedures, training,communications, and management of flight operations and the development of safety culture amongoperators with the goal of identifying and correcting factors known to contribute to accidents amonghelicopter air ambulances. (39) The FAA has also issued a special bulletin for developing andcritiquing air ambulance operator training programs and operating procedures that are specificallydesigned to prevent loss of control and CFIT accidents. (40) FAA inspectors will be looking for specific improvements topilot training to deal with inadvertent flight into low visibility conditions, flight solely by referenceto cockpit instruments, and recovery from unusual aircraft attitudes. (41) Inspectors will also belooking at air ambulance operators to see if they have implemented various procedures, such aspre-flight assessments of obstacles and terrain considerations along the route of flight, and the useof approved technologies to aid in-flight situation awareness in an effort to curtail accidents.

Applying Consistent Regulatory Requirements During All Phasesof Operation. The NTSB also noted that when patients are not on board, forexample during positioning flights or en route to an accident scene, air ambulance operators mayoperate under a less stringent set of regulations, because the FAA regards medical personnel onboard as essential crew members. (42) When operating under these less stringent regulations, airambulance operators have no set minimum requirements for in-flight visibility nor do any regulationspertaining to flight and duty time for pilots apply. The NTSB found that, of the 55 air ambulanceaccidents studied, 35 occurred while operating under these less stringent regulations without patientson board. In 10 of these accidents, the flights were being conducted in weather conditions thatwould not have met the minimum requirements for operation under the more stringent set ofcommercial regulations required for flights with patients on board. The NTSB concluded that, inits opinion, medical personnel on board do not meet the definition of required crew members forflight operational purposes, and therefore recommended that the FAA require air ambulanceoperators to comply with more stringent commercial flight regulations whenever medical personnelare on board, as they currently do when carrying patients.

The fact that air ambulance operations without patients are conducted under separateregulatory guidelines also has a potential impact on those operations conducted with patients onboard. This is because without any specific duty time regulations being applied to flights conductedwithout patients, such flights are not counted in a pilot's duty time totals. Therefore, lengthy flightoperations without patients on board could contribute to pilot fatigue and affect safety duringsubsequent flights with patients on board. While regulations currently include industry specificflight time and rest time requirements for helicopter air ambulance pilots, (43) flights flown withoutpatients are not required to be considered in complying with these regulations. Therefore,notwithstanding the NTSB's recommendation to conduct all flights with medical personnel on boardas commercial operations subject to specific duty time limitations, policy makers may consideralternative approaches to account for and limit pilot duty times in air ambulance operations in amanner that more accurately reflects actual flight time logged, regardless of whether patients are onboard or not.

Addressing Concerns Over Pilot Fatigue. Addressing the specific issue of pilot fatigue and duty time regulations among air ambulanceoperators is regarded by many aviation safety experts as being very important because thecombination of stress, rotating shift work, and operating at or near the minimal flight crew staffinglevels needed to maintain 24/7 operations is common across the industry and predisposes pilots toacute and chronic fatigue. (44) While fatigue has not been identified as a causal or contributingfactor in very many air ambulance accidents, this may largely be due to the difficulty insubstantiating the presence of fatigue following an accident. In 1988, the NTSB noted that, whilepilot fatigue had only been identified in one of the accidents it reviewed, pilot fatigue was suggestedby some in the EMS helicopter industry to be the primary cause of accidents. (45) Since that time, becauseno notable changes have taken place with regard to regulations or practices pertaining to pilot dutytimes across the industry, preventing pilot fatigue would appear to still be a significant objective forimproving safety in air ambulance operations. Therefore, in addition to addressing the broaderquestion of whether air ambulance flights should adhere to commercial flight regulations during allphases of a mission, including times when patients are not on board, policymakers may considerpossible changes in pilot duty time and flight time regulations to address concerns over the potentialrole of fatigue in the safety of flight operations.

To fully address the issue of pilot fatigue, specific regulations pertaining to flight time andrest requirements may need to be examined separately from the issue of requiring air ambulanceoperators to conform to other commercial operating regulations. In particular, those regulationspertaining to weather minimums and weather reporting requirements, when conducting flights withmedical personnel on board, may need to be examined as a separate issue. Specifically, airambulance operators have voiced concerns that applying existing commercial flight regulations topatient pick-up flights may significantly limit the ability of air ambulances to accept missions inreduced visibility. This, according to an industry trade group, is due to the fact that commercialregulations, as currently written, require approved weather reporting at the intended destination inorder to fly solely by reference to instruments. (46) This could significantly limit operators to visual flight conditionsonly. Working around this issue may require specific exemptions or a separate set of requirementsfor air ambulance operators. Although regulations and policies pertaining to weather and flight dutytime standards for air ambulance operations are both important issues for consideration, uniformlyapplying commercial flight regulations designed primarily for other purposes to all facets of airambulance operations may be an imperfect solution. Policy makers may consider tailoring theseregulations to the specific safety concerns and operational needs of the air ambulance industry bydealing with those regulations pertaining to weather minimums and those regulations pertaining topilot duty times as distinct policy issues.

Increasing Maintenance Oversight. As previouslymentioned, little attention has been given to the oversight of maintenance practices at facilities thatmaintain and repair air ambulance aircraft. However, consistent with this report's findings, anin-depth study of maintenance-related accidents found that about 23% of helicopter air ambulanceaccidents may be attributed, in part, to mechanical or maintenance issues. About one-third of theseaccidents were regarded as being the result of inadequate or improper maintenance. (47) Given that aviation safetyexperts have devoted considerable attention to airline maintenance practices, the lack of any specificfocus on maintenance of air ambulance operations is somewhat surprising, but this is likelyattributable to the fact that these maintenance safety issues are largely eclipsed by concerns overflight operational safety issues which account for the large majority of air ambulance crashes. Nevertheless, policymakers may consider whether additional oversight and scrutiny of air ambulancemaintenance practice may be able to provide additional insight into specific maintenance practicesthat compromise safety and available options for preventing maintenance-related incidents andaccidents.

Improving Aircraft Crashworthiness. Aircraftcrashworthiness and accident survivability is another regulatory issue that hasn't received muchattention with regard to air ambulance safety. A comprehensive examination of helicopter airambulance crash injuries and fatalities found that main cabin occupants of air ambulance helicoptershad about 4.5 times the risk of death or serious injury compared to occupants of otherhelicopters. (48) Thestudy concluded that the increased risk is likely attributable to cabin design modifications toaccommodate emergency medical missions. The study went on to identify greater relative risksamong lighter weight air ambulance helicopters (i.e., helicopters weighing less than 4,500 pounds)in crashes where there was a post-crash fire, among occupants not wearing shoulder harnesses, andfor mechanical-related crashes. For larger helicopters (i.e., helicopters weighing more than 4,500pounds), these distinctions between air ambulances and other helicopters were not as noticeable. This finding could have important implications if the service model for helicopter air ambulanceoperations continues to shift toward more autonomous private operators who may be more likely touse smaller, lighter-weight helicopters to keep aircraft acquisition and operating costs low. Thestudy concluded that the use of energy-absorbing seats that can handle greater crash forces incombination with lap and double-shoulder (five-point) harnesses, along with greater attention tocrashworthiness in designing cabin modifications for air ambulance operations could significantlyimprove occupant survivability and reduce the severity of crash-related injuries. Based on ananalysis of military helicopter crash data, the study also concluded that the use of helmets by flightcrews and medical crews could significantly reduce the risk of serious and fatal head injuries in acrash. Policymakers may consider whether specific design guidance or standards for seats, seatbelts,and interior design modifications as well as operational requirements for equipment such as shoulderharnesses and helmets could reduce fatalities and mitigate injury risks in air ambulance crashes. Equipment and design standards and requirements would likely have to strike a balance betweenproviding flight and medical crews with adequate protective measures while ensuring that thesesafety measures do not unduly prevent or interfere with patient care and other critical missionfunctions.

Implementing System Safety and Risk Management Principles

The degree to which safety principles are trained and practiced as a matter of routine withinthe air ambulance industry is a matter of considerable interest. While the FAA and tradeorganizations within the industry have issued guidance to operators to improve safety practices, (49) available accident statisticssuggest that these safety measures either have not yet been adequately adopted and implementedacross the industry or have not been particularly effective. The principal trade organization of airambulance operators, the Association of Air Medical Services, recently launched an initiative, called"Vision Zero", with the goal of attaining an industry-wide commitment to "...to reduce and eliminateerrors of consequence--those events within the transport medicine environment that result in seriousinjury or fatality -- and to reduce the entire spectrum of helicopter accidents by 80% over the nextdecade." (50) While theseefforts suggest that the industry as a whole is concerned about the current level of safety among airambulance operators and desires to take positive steps to improve safety, some, including the NTSB,argue that voluntary measures to improve safety such as this are insufficient, and certainsafety-related changes such as formal dispatch procedures and risk management practices shouldrequire mandatory, industry-wide compliance. Policymakers, either at the FAA or in Congress, willultimately have to weigh the merits of this argument and determine whether the safety benefits ofthese initiatives outweigh the costs associated with implementing them.

In its special study examining air ambulance accidents occurring between January 2002 andJanuary 2005, the NTSB found that a formal risk evaluation of the mission may have prevented 13of the 55 accidents reviewed. (51) However, the NTSB found that most operators have notimplemented a formal risk evaluation process, even though guidelines for setting up such a processhas been made available by the FAA. While the FAA has issued guidelines for implementing riskassessment programs for helicopter air ambulance operations, this material is only advisory in natureand is not required to be implemented. (52) Therefore, the NTSB formally recommended that the FAArequire all air ambulance operators to develop and implement flight risk evaluation programs andtrain all employees involved in decision-making and support of flight operations on participating inthese risk evaluation processes. (53)

In the airline industry, several initiatives to improve the collection and analysis ofsafety-related operational data have taken root and are now common practice. For example, aircarrier flight operational quality assurance (FOQA) programs collect extensive flight operationaldata. Using data mining techniques, operations that fall outside the defined parameters of safeoperations are identified and subsequently investigated to determine the circumstances surroundingthe incident, with the goal of reducing or eliminating events that compromise safety and could leadto an accident. Many airline safety programs also include internal reporting mechanisms andspecific "whistleblower" protections for employees that identify hazardous operational practices. Mechanisms have been put in place at several airlines, through a program called the Aviation SafetyAction Program (ASAP), allowing employees to voluntarily provide confidential reports regardingsafety concerns to the FAA with specific protections against negative consequences, except in thosecases involving suspected criminal actions or drug and alcohol misuse. (54) The objective of theseprograms is to provide a mechanism for preemptively identifying and correcting unsafe operationsbefore they lead to an accident. While comprehensive FOQA and ASAP programs may be toocomplex to effectively implement in the air ambulance industry, policymakers may consider whethersimilar approaches to information sharing and safety data analysis regarding critical safety issuescould be feasibly implemented across the air ambulance industry.

Training and Procedures for Flight and Medical Crews

It has been reported that, in 2000, representatives from the air ambulance industry approachedthe FAA with a proposal to require that air ambulance pilots and crew members receive training increw resource management (CRM). This type of training is mandatory for airline crews and focuseson how to effectively communicate risk information and use available resources to assess andmanage operational risks. (55) However, this proposal has not yet resulted in any FAArecommendations or regulatory proposals. Presently, there are no specific training requirement forpilots on topics such as CRM, risk management, and aeronautical decision making beyond thegeneral understanding of these topics required to obtain commercial pilot certification andappropriate ratings required for employment, such as helicopter and instrument ratings. Thesegeneral requirements are considered relatively minimal, and many safety experts argue that they donot receive adequate coverage in general flight training and pilot testing. Moreover, trainingreceived on these topics in the course of general flight training is not tailored to the specificoperational conditions and pressures that a pilot or crew member might experience in air ambulanceoperations. Thus, any specific training in dealing with operational risks unique to the flightenvironment of air ambulances is provided solely at the discretion of the operator. While someoperators provide this training in various forms, there is no industry standard for course content orobjectives for these types of training programs.

In the NTSB's 1988 study of helicopter air ambulance safety, it found that among the 14instrument-rated pilots involved in the crashes it examined, only one was current to fly solely byinstruments. (56) Similarly, a later analysis of pilot qualifications among air ambulance operators concluded that,while a greater percentage of air ambulance operators were instrument rated, a lack of instrumentcurrency or proficiency could be a detriment because instrument-rated pilots may overestimate theirinstrument training skills and press on in deteriorating conditions, despite not having adequate recentexperience and practice with instrument flight procedures. (57) Examining trainingpractices in the medical helicopter industry, the NTSB found a wide range of approaches to training,and noted that while many operators had well-defined training programs on paper, actual trainingdid not adequately address real-world conditions in the operational environment. The NTSBrecommended supplemental training material on aeronautical decision making be incorporated intoinitial and recurrent training for pilots. The NTSB also recommended that guidelines for FAAinspectors be revised to include reviews and approvals of initial and recurrent training for pilots toensure that they provide adequate levels of instruction on poor weather operations and accident sceneprocedures. (58) Therecently initiated FAA targeted inspection program for helicopter air ambulance operators (59) appears to directly addressthese concerns, and therefore, the effectiveness of ongoing FAA inspections of helicopter airambulance operators may be of particular interest as an issue for oversight of the FAA.

Besides flight crew training, there has also been a recent emphasis on providingaviation-specific training to other members of the air ambulance team, principally communicationsspecialists that dispatch and monitor air ambulance flights. The FAA has also suggested, but doesnot yet require, special training for ground communications specialists that dispatch and track airambulance flights covering aviation weather, flight operations, and flight tracking procedures. (60) Unlike the airlines, whichmust used FAA-certified dispatchers, air ambulance pilots are typically dispatched by EMSdispatchers or communication specialists who typically do not receive any formal training in aviationoperations or aviation weather. The NTSB has recommended that all air ambulance operatorsimplement formal flight dispatch procedures utilizing dedicated aviation dispatchers with formalaviation-specific knowledge and experience that can assist pilots in assessing weather data, providecomprehensive flight following, and aid pilots in making informed decisions whether to accept orcontinue a mission. (61) Policymakers will need to determine the feasability of requiring dedicated flight dispatchers in theair ambulance environment, and whether these services require an FAA certified dispatcher approvedunder existing FAA training and certification requirements for flight dispatchers. Alternatively,policymakers may evaluate whether mandatory training of existing emergency medicalcommunication specialists that work with or for air ambulance operators on aviation-specificdispatch procedures, aviation weather, aircraft capabilities, flight following, and so on, would meetthe intent of this recommendation. At least one company has already developed aviation-specifictraining for emergency medical communication specialists conforming to FAA recommendedtraining for ground communication specialists and hopes that this form of training will be mandatedfor the entire industry. (62)

Technology to Improve Safety in Low Visibility Conditions

Various technologies are available to improve visibility and pilot situation awareness ofterrain, obstacles, and weather. While these technologies may be of benefit to improve the safetyof air ambulance missions, some operators have expressed concern over the cost of installing andmaintaining these systems if doing so was made mandatory as the NTSB has recommended. Othershave questioned whether these technologies are appropriately suited for air ambulance use, orwhether modifications may be needed to tailor these devices to the unique mission profiles and needsof air ambulance operators, particularly for use on helicopter air ambulance missions.

Terrain Warning Systems. The NTSB's recentassessment of air ambulance safety included a recommendation to equip all helicopters and aircraftused in emergency medical services with terrain awareness and warning systems (TAWS, previouslyreferred to as enhanced ground proximity warning systems or EGPWS). (63) These devices providepilots with visual displays and audible alerts for terrain avoidance. Advanced Class A TAWS(TAWS-A) that rely on detailed terrain databases, Global Positioning System (GPS) data or othermeans of precise aircraft positioning, and radio altimeters to provide height above terrain informationare already required on all commercially operated aircraft with 10 or more passenger seats. Slightlyless sophisticated versions of TAWS, called Class B TAWS (TAWS-B), which do not include radioaltimeter height above terrain inputs, are required on all turbojets and turboprops, whethercommercially or privately operated, having six or more passenger seats. A typical TAWS-Binstallation may cost between $10,000 and $30,000 per aircraft depending on existing equipmentconfigurations. While some larger fixed-wing air ambulance aircraft may already fall under therequirement for TAWS-B installation if they have seating for six or more passengers, most helicopterand airplanes used as air ambulances do not. The NTSB specifically recommended that airambulance operators install TAWS and provide adequate training in the use of TAWS to their flightcrews, although it did not specify whether these aircraft should be equipped with TAWS-A orTAWS-B. (64) TheNTSB believes that TAWS could help prevent many controlled flight into terrain or CFIT accidents,which, as previously noted constituted one of the two most common causal factors cited in airambulance accidents.

Some operators have voiced concern, however, that false alarms generated by the TAWSsystems could distract pilots. These operators are worried that high false alarm rates -- particularlyamong helicopter air ambulances that frequently operate in close proximity to terrain in a mannernot typical of other aircraft and flight operations -- could largely negate any benefit that TAWS mayprovide in terms of improving pilot situation awareness regarding terrain clearance. While falsealarms are a potential concern when using TAWS systems because they may distract pilots, theNTSB and other aviation safety experts believe that the benefits of TAWS in improving pilotsituation awareness regarding the surround terrain far outweigh any negative effects that might occurdue to false alarms. However, further operational testing of TAWS usage in simulated air ambulancemissions may be needed to fully assess the suitability of TAWS in helicopter air ambulanceoperations.

Technologies to Enhance In-Flight Visibility. Inaddition to TAWS, a variety of technologies are available to improve pilot situation awarenessregarding terrain and obstacles during low visibility conditions and at night. As shown in Figure2 , nighttime visual conditions were a contributing factor in 14% and reduced visibility due toweather was a factor in 9% of the helicopter air ambulance crashes examined between 1991 and2004. Technologies to improve visibility under these restricted visibility conditions and at nightcould mitigate these types of accidents.

One broad category of available technologies to improve pilot vision, referred to as nightvision imaging systems (NVIS), rely on various forms of infrared sensors or cameras to enhance apilots view of the outside scene and avoid terrain and obstructions at night. One example of NVIStechnology is night vision goggles NVGs), used extensively in military helicopter operations, whichcan be worn by pilots to improve out-the-window visibility and aid in the avoidance of terrain andobstacles, such as power lines. An FAA study found that properly used NVGs can increase safety,enhance situation awareness, and reduce pilot workload during flights at night. (65) Although the FAA hasapproved the use of NVGs and recommends they be deployed for helicopter air ambulanceoperations, the NTSB found that most operators do not use NVGs because they have only beenrecently made available for non-military aviation use, equipping aircraft and training pilots isexpensive, and they can only be used effectively in sparsely populated areas where there isn't muchambient light. While the NTSB found that the use of night vision goggles may have mitigated 13of the 55 accidents it examined in its 2006 special study, it did not formally recommend NVG usage, recognizing that these systems are not usable in all situations.

Besides NVGs, other imaging systems are available for aviation use. Forward lookinginfrared cameras (FLIR) can provide enhanced images of night and low visibility scenes. FLIRimages can be projected on screens in the cockpit or through head-up displays (HUDs) that overlaythe enhanced image on top of the out the window scene. Recently certified enhanced vision systems(EVS) use similar principles to present images generated from special infrared cameras in thecockpit, usually on a HUD. EVS systems have been specifically certified by the FAA for use ininstrument flight operations for flying approaches to airports in poor visibility and at night andseveral business and commercial jets have been equipped with this new technology. Such systemscould potentially be used to improve visibility and situation awareness in air ambulance operations,especially for helicopter air ambulance operations that fly into unprepared landing sites wherenavigational aids and instrument approach procedures are not available to guide the pilot.

In addition to the aforementioned technologies that rely on cameras or sensors to enhancevision by capturing information outside the spectrum of what is visible to the human eye, the FAAhas also approved synthetic vision systems (SVS) for operational use. Unlike EVS, which relies onsensors or cameras to collect information from the outside scene, SVS relies on precise positioning,principally from very precise GPS receivers, (66) and accurate onboard terrain databases to present pilots with acomputer-generated image of the known terrain features and obstacles in and around the aircraft'sflight path. These images can be overlaid on top of navigational instruments, or like EVS, can beprojected on a head-up display to overlay on top of the out-the-window view. Coupled with highlyaccurate positioning information, SVS can potentially provide helicopter air ambulance pilots withaccurate navigation and terrain avoidance capabilities in low visibility and night conditions. Asthese technologies further advance, some combination of EVS and SVS imaging may be able toprovide air ambulance pilots with situation awareness of terrain and obstacles that matches, or insome cases, surpasses visual capabilities in unrestricted daylight conditions. Systems that combineEVS and SVS imaging are currently in the testing and certification process and may provide a meansto enhance cockpit situation awareness in air ambulance operations in the near future. (67)