ORIGINAL ARTICLE
A 26-year comparative review of United Kingdom helicopter emergency medical services crashes and serious incidents Adam Chesters, MSc FCEM, Phillip H. Grieve, BSc (Hons), and Timothy J. Hodgetts, CBE OStJ, Essex, United Kingdom
BACKGROUND: The use of helicopter emergency medical services (HEMS) has increased substantially in the United Kingdom since 1987. There are currently no data on the rate of crashes and serious incidents related to HEMS in the United Kingdom. The aims of this article were to present data from a 26-year period since the start of HEMS operations in the United Kingdom and to compare them with published data from Germany, Australia, and the United States. Factors identified as affecting the safety of HEMS operations will also be discussed. METHODS: A PubMed search was performed to retrieve published data on accident rates and safety discussions for international HEMS using the key words HEMS, helicopter, emergency medical services, accident, incident, and crash. The details of every helicopter crash in the United States since the beginning of HEMS operations was obtained and reviewed to identify those that involved HEMS aircraft. This novel UK information was compared with published data from three international systems. RESULTS: A total of 13 accidents or serious incidents involving HEMS aircraft were identified from Civil Aviation Authority records, only 1 of which was a fatal accident. It was estimated that approximately 230,000 HEMS missions occurred in the United Kingdom between 1987 and 2013, giving an absolute accident incidence of approximately 0.0057% and a fatal accident incidence of approximately 0.00043%. The accident and fatal accident rate per 10,000 missions in the United Kingdom was 0.57 and 0.04, respectively. This compares with published rates from Germany, Australia, and the United States with accident rate per 10,000 missions ranging between 0.57 and 0.75 and fatal accident rates per 10,000 missions ranging between 0.04 and 0.23. CONCLUSION: Accidents and serious incidents relating to HEMS operations in the United Kingdom have been comprehensively identified for the first time, allowing an estimation of overall accident and fatal accident rates and comparison with other countries’ HEMS operations. Data collection and analysis were hampered by obscurity of data sources and poor availability of data. In a time of increasing HEMS use in the United Kingdom, it is essential to be mindful of safety, and standardization of data collection will improve focus in this important area. (J Trauma Acute Care Surg. 2014;76: 1055Y1060. Copyright * 2014 by Lippincott Williams & Wilkins) KEY WORDS: Helicopter emergency medical services; fatal accident rate; helicopter crash; accident analysis; aeromedical transport.
T
he use of helicopter emergency medical services (HEMS) has increased significantly in the United Kingdom since the Cornwall Air Ambulance became the first air ambulance service to begin operations in 1987. In 2013, there were 24 air ambulance services in the United Kingdom, operating a total of 35 helicopters.1 Some are partly government funded and operated by the regional Ambulance Service, but the majority of them are funded by charitable organizations. There are no commercial air ambulance operations. The majority of these
Submitted: November 27, 2013, Revised: December 12, 2013, Accepted: December 17, 2013. From the Essex and Herts Air Ambulance Trust (A.C.), The Business Centre, Earls Colne Business Park, Earls Colne, Colchester, Essex; and East Anglian Air Ambulance (T.J.H.), Norwich, United Kingdom; and Reach Air Medical Services (P.H.G.), Santa Rosa, California. A.C. and P.H.G. regularly form part of operational helicopter emergency medical service crew, undertake missions at night, and under both visual and instrument flight rules. T.J.H. is the director of clinical quality and development for such a service. Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jtrauma.com). Address for reprints: Adam Chesters, MBChB MSc, Essex and Herts Air Ambulance Trust, The Business Centre, Earls Colne Business Park, Earls Colne, Colchester, Essex, CO6 2NS, United Kingdom; email: [email protected]. DOI: 10.1097/TA.0000000000000170
services currently operate during daylight hours only, responding mostly to primary emergencies in support of the regional ambulance services. All of the services operate twinengine aircraft, with five different types of helicopter in service in the United Kingdom: Eurocopter EC135 (17 of 35, 48.6%), MD Helicopters Explorer MD902 (11 of 35, 31.4%), Eurocopter AS365 Dauphin (3 of 35, 8.6%), Bolkow BK105 (2 of 35, 5.7%), and AgustaWestland AW109 (2 of 35, 5.7%). Crew configurations vary across the services, being made up of a combination of doctors, paramedics, HEMS crewmen, and pilots. All but one service usually operates with a single pilot. For a summary of key operational information for the UK helicopter air ambulances, including the approximate years of first service for each of their helicopter services, see Table 1. In 1998, the three-person crew of the Kent Air Ambulance died when the aircraft collided with power lines and crashed while returning from a HEMS mission. This incident remains the only fatal aviation accident related to HEMS in the United Kingdom to date. There are currently no data on the overall rate of crashes and serious incidents related solely to HEMS in the United Kingdom. Studies on HEMS accidents are rarely published, and international data relating to numbers of accidents are only present for three other countries or
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TABLE 1. Key Operational Information for HEMS Operators in the United Kingdom Air Ambulance Service Cornwall Devon Dorset and Somerset Hampshire and Isle of Wight Surrey and Sussex Kent Wiltshire London Great Western Thames Valley Essex Hertfordshire Midlands East Anglian Warwickshire and Northamptonshire Wales Derbyshire Leicestershire Rutland Lincolnshire and Nottinghamshire North West Yorkshire Great North Magpas Helimedix* Scotland Scottish
No. Helicopters
Current Helicopter Type
Year(s) of First Operation
1 2 1 1 1 1 1 1 1 1 1 1 3 2 1 3 1 1 2 2 3 1 2 Charity
EC135 EC135 EC135 EC135 MD902 MD902 MD902 MD902 BK105 MD902 MD902 MD902 EC135 EC135 AW109 EC135 AW109 MD902 EC135 MD902 AS365 MD902 EC135 1
1987 1992, 2008 2000 2007 1997 1989 1990 1989 2008 1999 1998 2008 1991, 1998, 1999 2001, 2007 2003 2001, 2003, 2006 2008 1994 1999, 2005 2000, 2007 1995, 2004, 2005 1997* 1989, 1993 BK105
*Magpas Helimedix first responded to medical emergencies in joint operations with the Police helicopter and then, between 2007 and 2010, used the East Anglian Air Ambulance helicopter 1. They acquired a dedicated aircraft in 2012.
regions.2Y6 The need for HEMS has been described in the context of impact on trauma patient mortality7 and in terms of financial costYtoYclinical benefit ratio,8 but these discussions have yet to be placed in the context of the overall safety of HEMS operations so far in the United Kingdom. There has been a recent move toward the expansion of HEMS to include night missions with an announcement by the Civil Aviation Authority (CAA) in May 2012 of a change to night flying
regulations, which will allow aircraft to operate under visual flight rules in the hours of darkness.9 Previously, all civil aircraft flying at night in the United Kingdom had to comply with instrument flight rules but from September 2012, this requirement was removed. This development requires a closer review of safety considerations of HEMS operations in general and specifically the identification of lessons and trends from other countries.
Figure 1. AAIB definitions of accident and serious incident. 1056
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Figure 2. Number of HEMS missions per year of service (UK numbers extrapolated from known German data).
In the United Kingdom, the CAA operates a Mandatory Occurrence Reporting scheme, which reflects both United Kingdom and European legislation.10 A reportable occurrence in relation to an aircraft is defined as ‘‘any incident which endangers or which, if not corrected, would endanger an aircraft, its occupants or any other person.’’ In the United Kingdom, the Air Accident Investigation Bureau (AAIB), a branch of the Department of Transport that is independent of the CAA, investigates all aviation accidents and serious incidents. The AAIB definition of an accident and a serious incident is shown in Figure 1. The aims of this article were to present crash and serious incident data over a 26-year period since the start of HEMS operations in the United Kingdom and to compare these data with published data from Germany, Australia, and the United States. Factors identified as affecting the safety of HEMS operations will also be discussed in the context of UK operations and the data presented.
PATIENTS AND METHODS A request was submitted to the CAA for a list of all turbine helicopter crashes and serious incidents between April 1, 1987, (the first date of operations of Cornwall Air Ambulance) and March 31, 2013. In addition, a search of the online AAIB database of reports for the same date range and with the filters ‘‘general aviationYrotorcraft’’ and ‘‘commercial air transportYrotorcraft’’ was performed. The following categories of incidents were excluded: ‘‘foreign accidents,’’ ‘‘military accidents,’’ and those outside of the desired date range. After application of the exclusion criteria, the two lists generated were used to cross-reference each other and produce a single list of all remaining accidents and serious incidents. This list was hand-searched to identify those occurrences with aircraft engaged in HEMS activity. The full AAIB report of all identified incidents was obtained. In addition, a PubMed search was performed to retrieve published data on accident rates and safety discussions for international HEMS. All Boolean combinations of the key words HEMS, helicopter, emergency medical services, accident, incident,
and crash were used to identify relevant studies. The abstracts of identified studies were reviewed, and the full text of relevant articles was obtained. Secondary references of identified articles were scrutinized for any studies missed by the original search criteria. Data were compared on the basis of accident rate per 10,000 missions, which is a common reporting method across the associated literature. For the relevant data, it was ensured that the definitions of ‘‘accident’’ and ‘‘incident’’ were similar, and it was clarified whether reported rates included accidents, incidents, or both. To analyze the data in this way, the total number of HEMS missions in the United Kingdom is required. These data have not routinely been collected, and therefore, accurate numbers do not exist. To establish a reasonable figure on which to base all further analysis, estimates of the total number of UK HEMS missions were obtained from the only published source of data, the Association of Air Ambulances (AAA) in the United Kingdom, which published data for the year 2006. By contrast, the total number of HEMS missions in Germany from the commencement of operations in 1970 to the end of 2009 has been published. As a fellow European country, albeit with a longer-standing and perhaps differently tasked and used HEMS operation, it has been assumed for the purposes of this analysis that there is a similar trend in increasing HEMS use. To account for larger absolute numbers of HEMS missions in Germany, the known figure for the United Kingdom in 2006 was calculated as a percentage of the known figure for Germany in the same year. With the use of the same percentage figure (approximately 20%), the extrapolated mean number of missions per year in the United Kingdom was calculated based on the mean number of German HEMS missions per year. This was then multiplied to represent a period of 26 years to allow comparison with international data and rounded to the nearest 1,000 as a working figure for the purposes of convenient analysis. As a check of approximate validity of this extrapolation, the number of missions per helicopter in Germany for the first 20 years of operations was calculated based on published data. The trend approximately intersects the known number of
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TABLE 2. Summary of HEMS Accidents and Incidents Reported to the CAA and AAIB Between 1987 and 2013 Year
Aircraft Type
Persons on Board
Injuries on Board
Aircraft Damage
Stage of Flight
Accident or Serious Incident
1991 1993 1997 1998 2000 2001 2001 2002 2005 2010 2006 2011
Aerospatiale AS355 Aerospatiale SA365 Aerospatiale SA365 Aerospatiale AS355 Agusta A109 Bolkow BK105 Agusta A109 Bolkow BK105 MD 900 Explorer Aerospatiale SA365 MD 900 Explorer MD 900 Explorer
1 4 4 3 3 3 3 4 4 4 4 4
None None None 3 fatal 3 minor 3 minor 2 minor None None None None None
Rotor blades and tail Landing gear Rotor blade Destroyed Extensive Tail rotor and skid Tail, all blades, landing gear Rotor blade Rotor blades Cabin door Rotor blades/head and gearbox None
Landing Ground Landing Cruise Landing Landing Cruise Take off Landing Cruise Landing Take off
A A A A A A A A A SI A SI
A, accident; SI, serious incident.
missions per helicopter in the United Kingdom for the year 2006 (the 19th year of HEMS operations in the United Kingdom). When the extrapolated number of missions per helicopter in the United Kingdom is used to estimate yearly number of missions, the total number approximates the extrapolation of the 20% sum of the mean number of German HEMS missions. For details of these calculations, see Figure 2 and Supplementary Digital Content 1, at http://links.lww.com/TA/A386. A final working number of 221,000 to 246,000 HEMS missions in the United Kingdom for the period 1987 to 2009 were rounded to 230,000 for the purposes of further calculation.
RESULTS Identification of UK Accident and Incident Data and Data for Comparison The CAA database interrogation returned 569 reports of turbine helicopter crashes or serious incidents between January 1, 1987, and August 23. 2013. A total of 214 foreign accidents, 21 military accidents, and 4 accidents occurring outside the date range of HEMS operations in the United Kingdom were excluded, resulting in a total of 330 incidents for further review. The result of the AAIB database search was used to cross-reference each of these 330 incidents by hand. Following this process, a total of 12 accidents or serious incidents involving HEMS aircraft were identified, only 1 of which was a fatal accident (involving an aircraft type that is no longer used in the UK HEMS industry). After review of
the individual reports, one further incident was identified because it was mentioned in a report involving the same aircraft but had not previously been reported to the AAIB or CAA in its own right. This gave a total of 13 accidents or serious incidents to analyze. Following a PubMed search, relevant articles were found, which described comparable incident, accident, and fatality rates in three countries as follows: the United States, Germany, and Australia. During the course of the literature search, unpublished data pertaining to HEMS safety in the United States, which were available in two US government reports, were identified.11,12
Description of UK Data and International Comparison During the period April 1987 to August 2013, an estimated total of 230,000 HEMS missions have been carried out in the United Kingdom. In the same period, there have been a total of 13 accidents or serious incidents reported to the CAA and investigated by the AAIB. One of these occurrences was a fatal crash. These incidents are summarized in Table 2. During the time frame studied, an absolute accident incidence of approximately 0.0057% and a fatal accident incidence of approximately 0.00043% were found. Both the accident rate and the fatal accident rate were calculated in terms of rate per 10,000 missions to allow direct comparison with published data from the other three countries. This comparison is shown in Table 3. The phase of flight in which the accident or incident occurred was presented by one other source, and this was
TABLE 3. Comparison of HEMS Accidents and Fatal Accidents per 10,000 Missions Country Australia 1 Germany 2 USA 3, 4 United Kingdom
Years
Accident Rate per 10,000 Missions
Fatal Accident Rate per 10,000 Missions
1992Y2002 1970Y2009 2000Y2009 1987Y2013
0.60 0.57* 0.75 0.57**
0.20 0.11 0.23 0.04
*German rate includes accidents and serious incidents as defined by the Federal Agency for Flight Accident Investigation. **UK rate includes accidents and serious incidents (as defined by the AAIB). US and Australian rates are for accidents only.
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TABLE 4. Phase of Flight in Which Accident or Incident Occurred Based on UK and German Data Flight Phase Take off Cruise Landing Total
Germany 1970Y2009, United Kingdom 1987Y2013, n (%) n (%) 29 (29.3) 26 (26.3) 44 (44.6) 99
3 (23.1) 3 (23.1) 7 (53.8) 13
p
0.53
statistically similar to the phase of flight occurrences in our study (p=0.53). These data are presented in Table 4.
DISCUSSION This study is the only study to date that identifies and analyzes all accidents and serious incidents related to HEMS operations in the United Kingdom since 1987, when the first air ambulance mission was undertaken in this country. Although formal statistical analysis has not been undertaken because of the requirement for estimation of total number of missions that was used to calculate the accident and incident rate, the rates presented compare favorably with other countries’ published data. This is important because the perception of a low total number of accidents and incidents in the United Kingdom (compared with countries with higher total HEMS missions) is likely to be a function of total number of HEMS missions rather than the existence of an inherently more safe system in the United Kingdom. The recognition and publication of a similar and standardized accident rate (rate per 10,000 missions) may facilitate operations governance through identification of systems whose rates are considerably higher than might be considered ‘‘acceptable.’’ Most (9 of 13, 69%) of the occurrences identified were without injury to the crew on board. One accident resulted in fatalities of all on board, and the remaining three (23%) resulted in minor injuries only. This is similar to the results from the German database analysis reported by Hinkelbein et al.3 An analysis of medical helicopter accidents in the United States during a 10-year period reported that 37 (44%) of 84 resulted in neither injury nor fatality.2 In this study, 27 (32%) of 84 involved fatalities of persons on board the aircraft. For the single fatal accident in the United Kingdom, the AAIB report confirms that the accident occurred away from the airfield and was associated with a postcrash fire. These two variables have been shown to be predictive of fatality associated with aviation crashes, with one analysis of composite risk demonstrating a 62% chance of pilot fatality when both of these factors are present.13 In another study, 76% of crashes with postcrash fire were fatal compared with 29% of other crashes.14 It is noteworthy that the only HEMS accident in the United Kingdom that was associated with fire of any kind was also the only fatal accident. There are limitations with this study. All accident rate calculations are based on an estimated total number of missions flown since 1987 extrapolated from German data, with a single published report of annual HEMS missions for the United Kingdom in 2006 as a reference point. No other
information is available because no single body has specifically collected aviation data regarding HEMS operations. The AAA has begun collecting this information from member organizations, and it is envisaged that such data will progressively become more available. Two trend calculations have been performed in an attempt to validate the approximate mission numbers for the United Kingdom, but it is accepted that the true number of missions flown (and therefore the true accident rates) for this period will never be known. The calculated rates seem feasible in that they are roughly comparable with data from other countries, which are based on actual reported numbers. There is a limitation of comparing different international systems and of comparing all HEMS operations in a single country as a group. There will be variance in organizations’ standard operating procedures such as range of operations, crew composition, instrument rating of the pilot, response to primacy incidents, secondary transfers, and so on. Such variance makes it difficult to produce a national picture. This is offset to some degree by the tight regulations of the CAA such that all HEMS operations will operate according to the same overarching set of flight rules. In comparing international services, it is recognized that these flight rules may differ. The relative influence of operational differences, such as flying at night, requires further analysis but may not be substantial. For example, in 2010, of the seven fatal accidents involving HEMS aircraft in the United States, three occurred at night and four occurred during daylight hours.15 In contrast, a simulator-based study reported that instrument-proficient pilots more safely managed an unexpected encounter with instrument meteorologic conditions than those without instrument rating.16 This latter point is relevant because inadvertent requirement for instrument meteorologic conditions has been associated with an increased risk of aviation crashes.13 In the United Kingdom, HEMS operations may be changing. The change of regulations by the CAA to allow visual flight rule flights during the hours of darkness have led to some services declaring an intention to operate at night. It should be noted that the UK accident rates presented here represent a period over which no (or very few) HEMS aircraft operated at night. It should also be noted that extending flying hours would also increase the absolute number of HEMS missions flown in the United Kingdom with the associated implications to the absolute number of accidents with an accident rate similar to that of international countries already operating far more frequently. The current national picture in the United Kingdom is one of individual air ambulance services having accountability for their own operations governance, while remaining ultimately accountable to the CAA. The AAA17 is a membership body for those organizations that form part of the air ambulance services in the United Kingdom, which emphasizes the importance of close cooperation between members. The AAA operates to a code of conduct and has an important role in interservice communication and some elements of voluntary data collection but does not have any overarching regulatory or data recording capacity. In contrast, the National Police Aviation Service18 became operational in 2012 and provides centralized air support to the 43 police forces in England and
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Wales, replacing the previous structure whereby individual police forces operate their own helicopters. The National Police Aviation Service operates under a UK legal statute that requires police air support to be carried out through a single national collaboration. Centralization of this allied emergency service may provide a more unified regulatory environment, with a clearer national oversight and may facilitate important data collection and national industry communication.
CONCLUSION Accidents and serious incidents relating to HEMS operations in the United Kingdom have been comprehensively identified for the first time. This has allowed an estimation of overall accident and fatal accident rates and comparison of these rates with those of other countries’ HEMS operations. In a time of potential for the increased use of HEMS aircraft in the United Kingdom, it is essential to remain mindful of safety. This could be facilitated by the central collection of basic operational data such as mission frequency and characteristics, which will allow accident rates to be monitored and compared between services, between modes of emergency medical transport, and internationally. The use of HEMS in prehospital emergency medicine and interfaculty transfer must be considered in the context of both clinical efficacy and operational safety. AUTHORSHIP A.C. had the idea for the research and assisted with the data collection and analysis. P.H.G. assisted with the data collection and analysis. A.C., P.H.G., and T.J.H. participated in the construction, review, and revision of the manuscript. All listed authors read and approved the final manuscript submission.
ACKNOWLEDGMENT We acknowledge the helpful contribution of Professor Timothy Harris and Captain Nicola Smith in the review of key parts of the final manuscript.
DISCLOSURE The authors declare no conflicts of interest.
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REFERENCES 1. UK HEMS. Information about your local air ambulance. 2013. Available at: www.ukhems.co.uk/localairambulance.html. Accessed October 15, 2013. 2. Bledsoe B, Smith M. Medical helicopter accidents in the United States: a 10-year review. J Trauma. 2004;56(6):1325Y1329. 3. Hinkelbein J, Schwalbe M, Neuhaus C, Wetsch W, Genzwurker H. Incidents, accidents and fatalities in 40 years of German helicopter medical system operations. Eur J Anaesthesiol. 2011;28:766Y773. 4. Holland J, Cooksley D. Safety of helicopter aeromedical transport in Australia: a retrospective study. Med J Aus. 2005;182:17Y19. 5. Hinkelbein J, Dambier M, Viergutz T, Genzwurker H. A 6-year analysis of German emergency medical services helicopter crashes. J Trauma. 2008; 64:204Y210. 6. Thies K, Sep D, Derksen R. How safe are HEMS-programmes in Germany? A retrospective analysis. Resuscitation. 2006;68(3):359Y363. 7. Butler D, Anwar I, Willet K. Is is the H or the EMS in HEMS that has an impact on trauma mortality? A systematic review of the evidence. Emerg Med J. 2010;27(9):692Y701. 8. Taylor C, Stevenson M, Jan S, Middleton P, Fitzharris M, Myburgh J. A systematic review of the costs and benefits of helicopter emergency medical services. Injury. 2010;41(1):10Y20. 9. Civil Aviation Authority. IN-2012/145: Introduction of Visual Flight Rules (VFR) at Night in the UK. 2012. Available at: www.caa.co.uk/docs/33/ informationnotice2012124corrected.pdf. Accessed October 15, 2013. 10. Civil Aviation Authority. CAP: Mandatory Occurance Reporting Scheme. 2011. Available at: www.caa.co.uk. Accessed October 15, 2013. 11. National Transportation Safety Board. Helicopter Emergency Medical Services. Public Hearing. Washington, DC; 2009. 12. National Transportation Safety Board. Review of US Civil Aviation Accidents: Review of Aircraft Accident Data, 2007Y2009. Washington, DC; 2011. 13. Guohua L, Gebrekristos H, Baker S. FIA Score: a simple risk index for predicting fatality in aviation crashes. J Trauma. 2008;65:1278Y1283. 14. Baker S, Grabowski J, Dodd RSD, Lamb M, Li G. EMS helicopter crashes: what influences fatal outcome? Ann Emerg Med. 2006;47(4):351Y356. 15. National Transportation Safety Board. Review of US Civil Aviation Accidents. Review of Aircraft Accident Data 2010. Washington, DC; 2012. 16. Wuerz R, O’Neal R. Role of pilot instrument proficiency in the safety of helicopter emerency medical services. Acad Emerg Med. 1997;4(10): 972Y975. 17. Association of Air Ambulances. Available at: http://www.associationofair ambulances.co.uk/. Accessed December 12, 2013. 18. West Yorkshire Police. National Police Aviation Service. 2012. Available at: http://www.westyorkshire.police.uk/npas. Accessed December 12, 2013.
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A 26-year comparative review of United Kingdom helicopter emergency medical services crashes and serious incidents Adam Chesters, MSc FCEM, Phillip H. Grieve, BSc (Hons), and Timothy J. Hodgetts, CBE OStJ, Essex, United Kingdom
BACKGROUND: The use of helicopter emergency medical services (HEMS) has increased substantially in the United Kingdom since 1987. There are currently no data on the rate of crashes and serious incidents related to HEMS in the United Kingdom. The aims of this article were to present data from a 26-year period since the start of HEMS operations in the United Kingdom and to compare them with published data from Germany, Australia, and the United States. Factors identified as affecting the safety of HEMS operations will also be discussed. METHODS: A PubMed search was performed to retrieve published data on accident rates and safety discussions for international HEMS using the key words HEMS, helicopter, emergency medical services, accident, incident, and crash. The details of every helicopter crash in the United States since the beginning of HEMS operations was obtained and reviewed to identify those that involved HEMS aircraft. This novel UK information was compared with published data from three international systems. RESULTS: A total of 13 accidents or serious incidents involving HEMS aircraft were identified from Civil Aviation Authority records, only 1 of which was a fatal accident. It was estimated that approximately 230,000 HEMS missions occurred in the United Kingdom between 1987 and 2013, giving an absolute accident incidence of approximately 0.0057% and a fatal accident incidence of approximately 0.00043%. The accident and fatal accident rate per 10,000 missions in the United Kingdom was 0.57 and 0.04, respectively. This compares with published rates from Germany, Australia, and the United States with accident rate per 10,000 missions ranging between 0.57 and 0.75 and fatal accident rates per 10,000 missions ranging between 0.04 and 0.23. CONCLUSION: Accidents and serious incidents relating to HEMS operations in the United Kingdom have been comprehensively identified for the first time, allowing an estimation of overall accident and fatal accident rates and comparison with other countries’ HEMS operations. Data collection and analysis were hampered by obscurity of data sources and poor availability of data. In a time of increasing HEMS use in the United Kingdom, it is essential to be mindful of safety, and standardization of data collection will improve focus in this important area. (J Trauma Acute Care Surg. 2014;76: 1055Y1060. Copyright * 2014 by Lippincott Williams & Wilkins) KEY WORDS: Helicopter emergency medical services; fatal accident rate; helicopter crash; accident analysis; aeromedical transport.
T
he use of helicopter emergency medical services (HEMS) has increased significantly in the United Kingdom since the Cornwall Air Ambulance became the first air ambulance service to begin operations in 1987. In 2013, there were 24 air ambulance services in the United Kingdom, operating a total of 35 helicopters.1 Some are partly government funded and operated by the regional Ambulance Service, but the majority of them are funded by charitable organizations. There are no commercial air ambulance operations. The majority of these
Submitted: November 27, 2013, Revised: December 12, 2013, Accepted: December 17, 2013. From the Essex and Herts Air Ambulance Trust (A.C.), The Business Centre, Earls Colne Business Park, Earls Colne, Colchester, Essex; and East Anglian Air Ambulance (T.J.H.), Norwich, United Kingdom; and Reach Air Medical Services (P.H.G.), Santa Rosa, California. A.C. and P.H.G. regularly form part of operational helicopter emergency medical service crew, undertake missions at night, and under both visual and instrument flight rules. T.J.H. is the director of clinical quality and development for such a service. Supplemental digital content is available for this article. Direct URL citations appear in the printed text, and links to the digital files are provided in the HTML text of this article on the journal’s Web site (www.jtrauma.com). Address for reprints: Adam Chesters, MBChB MSc, Essex and Herts Air Ambulance Trust, The Business Centre, Earls Colne Business Park, Earls Colne, Colchester, Essex, CO6 2NS, United Kingdom; email: [email protected]. DOI: 10.1097/TA.0000000000000170
services currently operate during daylight hours only, responding mostly to primary emergencies in support of the regional ambulance services. All of the services operate twinengine aircraft, with five different types of helicopter in service in the United Kingdom: Eurocopter EC135 (17 of 35, 48.6%), MD Helicopters Explorer MD902 (11 of 35, 31.4%), Eurocopter AS365 Dauphin (3 of 35, 8.6%), Bolkow BK105 (2 of 35, 5.7%), and AgustaWestland AW109 (2 of 35, 5.7%). Crew configurations vary across the services, being made up of a combination of doctors, paramedics, HEMS crewmen, and pilots. All but one service usually operates with a single pilot. For a summary of key operational information for the UK helicopter air ambulances, including the approximate years of first service for each of their helicopter services, see Table 1. In 1998, the three-person crew of the Kent Air Ambulance died when the aircraft collided with power lines and crashed while returning from a HEMS mission. This incident remains the only fatal aviation accident related to HEMS in the United Kingdom to date. There are currently no data on the overall rate of crashes and serious incidents related solely to HEMS in the United Kingdom. Studies on HEMS accidents are rarely published, and international data relating to numbers of accidents are only present for three other countries or
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TABLE 1. Key Operational Information for HEMS Operators in the United Kingdom Air Ambulance Service Cornwall Devon Dorset and Somerset Hampshire and Isle of Wight Surrey and Sussex Kent Wiltshire London Great Western Thames Valley Essex Hertfordshire Midlands East Anglian Warwickshire and Northamptonshire Wales Derbyshire Leicestershire Rutland Lincolnshire and Nottinghamshire North West Yorkshire Great North Magpas Helimedix* Scotland Scottish
No. Helicopters
Current Helicopter Type
Year(s) of First Operation
1 2 1 1 1 1 1 1 1 1 1 1 3 2 1 3 1 1 2 2 3 1 2 Charity
EC135 EC135 EC135 EC135 MD902 MD902 MD902 MD902 BK105 MD902 MD902 MD902 EC135 EC135 AW109 EC135 AW109 MD902 EC135 MD902 AS365 MD902 EC135 1
1987 1992, 2008 2000 2007 1997 1989 1990 1989 2008 1999 1998 2008 1991, 1998, 1999 2001, 2007 2003 2001, 2003, 2006 2008 1994 1999, 2005 2000, 2007 1995, 2004, 2005 1997* 1989, 1993 BK105
*Magpas Helimedix first responded to medical emergencies in joint operations with the Police helicopter and then, between 2007 and 2010, used the East Anglian Air Ambulance helicopter 1. They acquired a dedicated aircraft in 2012.
regions.2Y6 The need for HEMS has been described in the context of impact on trauma patient mortality7 and in terms of financial costYtoYclinical benefit ratio,8 but these discussions have yet to be placed in the context of the overall safety of HEMS operations so far in the United Kingdom. There has been a recent move toward the expansion of HEMS to include night missions with an announcement by the Civil Aviation Authority (CAA) in May 2012 of a change to night flying
regulations, which will allow aircraft to operate under visual flight rules in the hours of darkness.9 Previously, all civil aircraft flying at night in the United Kingdom had to comply with instrument flight rules but from September 2012, this requirement was removed. This development requires a closer review of safety considerations of HEMS operations in general and specifically the identification of lessons and trends from other countries.
Figure 1. AAIB definitions of accident and serious incident. 1056
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Figure 2. Number of HEMS missions per year of service (UK numbers extrapolated from known German data).
In the United Kingdom, the CAA operates a Mandatory Occurrence Reporting scheme, which reflects both United Kingdom and European legislation.10 A reportable occurrence in relation to an aircraft is defined as ‘‘any incident which endangers or which, if not corrected, would endanger an aircraft, its occupants or any other person.’’ In the United Kingdom, the Air Accident Investigation Bureau (AAIB), a branch of the Department of Transport that is independent of the CAA, investigates all aviation accidents and serious incidents. The AAIB definition of an accident and a serious incident is shown in Figure 1. The aims of this article were to present crash and serious incident data over a 26-year period since the start of HEMS operations in the United Kingdom and to compare these data with published data from Germany, Australia, and the United States. Factors identified as affecting the safety of HEMS operations will also be discussed in the context of UK operations and the data presented.
PATIENTS AND METHODS A request was submitted to the CAA for a list of all turbine helicopter crashes and serious incidents between April 1, 1987, (the first date of operations of Cornwall Air Ambulance) and March 31, 2013. In addition, a search of the online AAIB database of reports for the same date range and with the filters ‘‘general aviationYrotorcraft’’ and ‘‘commercial air transportYrotorcraft’’ was performed. The following categories of incidents were excluded: ‘‘foreign accidents,’’ ‘‘military accidents,’’ and those outside of the desired date range. After application of the exclusion criteria, the two lists generated were used to cross-reference each other and produce a single list of all remaining accidents and serious incidents. This list was hand-searched to identify those occurrences with aircraft engaged in HEMS activity. The full AAIB report of all identified incidents was obtained. In addition, a PubMed search was performed to retrieve published data on accident rates and safety discussions for international HEMS. All Boolean combinations of the key words HEMS, helicopter, emergency medical services, accident, incident,
and crash were used to identify relevant studies. The abstracts of identified studies were reviewed, and the full text of relevant articles was obtained. Secondary references of identified articles were scrutinized for any studies missed by the original search criteria. Data were compared on the basis of accident rate per 10,000 missions, which is a common reporting method across the associated literature. For the relevant data, it was ensured that the definitions of ‘‘accident’’ and ‘‘incident’’ were similar, and it was clarified whether reported rates included accidents, incidents, or both. To analyze the data in this way, the total number of HEMS missions in the United Kingdom is required. These data have not routinely been collected, and therefore, accurate numbers do not exist. To establish a reasonable figure on which to base all further analysis, estimates of the total number of UK HEMS missions were obtained from the only published source of data, the Association of Air Ambulances (AAA) in the United Kingdom, which published data for the year 2006. By contrast, the total number of HEMS missions in Germany from the commencement of operations in 1970 to the end of 2009 has been published. As a fellow European country, albeit with a longer-standing and perhaps differently tasked and used HEMS operation, it has been assumed for the purposes of this analysis that there is a similar trend in increasing HEMS use. To account for larger absolute numbers of HEMS missions in Germany, the known figure for the United Kingdom in 2006 was calculated as a percentage of the known figure for Germany in the same year. With the use of the same percentage figure (approximately 20%), the extrapolated mean number of missions per year in the United Kingdom was calculated based on the mean number of German HEMS missions per year. This was then multiplied to represent a period of 26 years to allow comparison with international data and rounded to the nearest 1,000 as a working figure for the purposes of convenient analysis. As a check of approximate validity of this extrapolation, the number of missions per helicopter in Germany for the first 20 years of operations was calculated based on published data. The trend approximately intersects the known number of
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TABLE 2. Summary of HEMS Accidents and Incidents Reported to the CAA and AAIB Between 1987 and 2013 Year
Aircraft Type
Persons on Board
Injuries on Board
Aircraft Damage
Stage of Flight
Accident or Serious Incident
1991 1993 1997 1998 2000 2001 2001 2002 2005 2010 2006 2011
Aerospatiale AS355 Aerospatiale SA365 Aerospatiale SA365 Aerospatiale AS355 Agusta A109 Bolkow BK105 Agusta A109 Bolkow BK105 MD 900 Explorer Aerospatiale SA365 MD 900 Explorer MD 900 Explorer
1 4 4 3 3 3 3 4 4 4 4 4
None None None 3 fatal 3 minor 3 minor 2 minor None None None None None
Rotor blades and tail Landing gear Rotor blade Destroyed Extensive Tail rotor and skid Tail, all blades, landing gear Rotor blade Rotor blades Cabin door Rotor blades/head and gearbox None
Landing Ground Landing Cruise Landing Landing Cruise Take off Landing Cruise Landing Take off
A A A A A A A A A SI A SI
A, accident; SI, serious incident.
missions per helicopter in the United Kingdom for the year 2006 (the 19th year of HEMS operations in the United Kingdom). When the extrapolated number of missions per helicopter in the United Kingdom is used to estimate yearly number of missions, the total number approximates the extrapolation of the 20% sum of the mean number of German HEMS missions. For details of these calculations, see Figure 2 and Supplementary Digital Content 1, at http://links.lww.com/TA/A386. A final working number of 221,000 to 246,000 HEMS missions in the United Kingdom for the period 1987 to 2009 were rounded to 230,000 for the purposes of further calculation.
RESULTS Identification of UK Accident and Incident Data and Data for Comparison The CAA database interrogation returned 569 reports of turbine helicopter crashes or serious incidents between January 1, 1987, and August 23. 2013. A total of 214 foreign accidents, 21 military accidents, and 4 accidents occurring outside the date range of HEMS operations in the United Kingdom were excluded, resulting in a total of 330 incidents for further review. The result of the AAIB database search was used to cross-reference each of these 330 incidents by hand. Following this process, a total of 12 accidents or serious incidents involving HEMS aircraft were identified, only 1 of which was a fatal accident (involving an aircraft type that is no longer used in the UK HEMS industry). After review of
the individual reports, one further incident was identified because it was mentioned in a report involving the same aircraft but had not previously been reported to the AAIB or CAA in its own right. This gave a total of 13 accidents or serious incidents to analyze. Following a PubMed search, relevant articles were found, which described comparable incident, accident, and fatality rates in three countries as follows: the United States, Germany, and Australia. During the course of the literature search, unpublished data pertaining to HEMS safety in the United States, which were available in two US government reports, were identified.11,12
Description of UK Data and International Comparison During the period April 1987 to August 2013, an estimated total of 230,000 HEMS missions have been carried out in the United Kingdom. In the same period, there have been a total of 13 accidents or serious incidents reported to the CAA and investigated by the AAIB. One of these occurrences was a fatal crash. These incidents are summarized in Table 2. During the time frame studied, an absolute accident incidence of approximately 0.0057% and a fatal accident incidence of approximately 0.00043% were found. Both the accident rate and the fatal accident rate were calculated in terms of rate per 10,000 missions to allow direct comparison with published data from the other three countries. This comparison is shown in Table 3. The phase of flight in which the accident or incident occurred was presented by one other source, and this was
TABLE 3. Comparison of HEMS Accidents and Fatal Accidents per 10,000 Missions Country Australia 1 Germany 2 USA 3, 4 United Kingdom
Years
Accident Rate per 10,000 Missions
Fatal Accident Rate per 10,000 Missions
1992Y2002 1970Y2009 2000Y2009 1987Y2013
0.60 0.57* 0.75 0.57**
0.20 0.11 0.23 0.04
*German rate includes accidents and serious incidents as defined by the Federal Agency for Flight Accident Investigation. **UK rate includes accidents and serious incidents (as defined by the AAIB). US and Australian rates are for accidents only.
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TABLE 4. Phase of Flight in Which Accident or Incident Occurred Based on UK and German Data Flight Phase Take off Cruise Landing Total
Germany 1970Y2009, United Kingdom 1987Y2013, n (%) n (%) 29 (29.3) 26 (26.3) 44 (44.6) 99
3 (23.1) 3 (23.1) 7 (53.8) 13
p
0.53
statistically similar to the phase of flight occurrences in our study (p=0.53). These data are presented in Table 4.
DISCUSSION This study is the only study to date that identifies and analyzes all accidents and serious incidents related to HEMS operations in the United Kingdom since 1987, when the first air ambulance mission was undertaken in this country. Although formal statistical analysis has not been undertaken because of the requirement for estimation of total number of missions that was used to calculate the accident and incident rate, the rates presented compare favorably with other countries’ published data. This is important because the perception of a low total number of accidents and incidents in the United Kingdom (compared with countries with higher total HEMS missions) is likely to be a function of total number of HEMS missions rather than the existence of an inherently more safe system in the United Kingdom. The recognition and publication of a similar and standardized accident rate (rate per 10,000 missions) may facilitate operations governance through identification of systems whose rates are considerably higher than might be considered ‘‘acceptable.’’ Most (9 of 13, 69%) of the occurrences identified were without injury to the crew on board. One accident resulted in fatalities of all on board, and the remaining three (23%) resulted in minor injuries only. This is similar to the results from the German database analysis reported by Hinkelbein et al.3 An analysis of medical helicopter accidents in the United States during a 10-year period reported that 37 (44%) of 84 resulted in neither injury nor fatality.2 In this study, 27 (32%) of 84 involved fatalities of persons on board the aircraft. For the single fatal accident in the United Kingdom, the AAIB report confirms that the accident occurred away from the airfield and was associated with a postcrash fire. These two variables have been shown to be predictive of fatality associated with aviation crashes, with one analysis of composite risk demonstrating a 62% chance of pilot fatality when both of these factors are present.13 In another study, 76% of crashes with postcrash fire were fatal compared with 29% of other crashes.14 It is noteworthy that the only HEMS accident in the United Kingdom that was associated with fire of any kind was also the only fatal accident. There are limitations with this study. All accident rate calculations are based on an estimated total number of missions flown since 1987 extrapolated from German data, with a single published report of annual HEMS missions for the United Kingdom in 2006 as a reference point. No other
information is available because no single body has specifically collected aviation data regarding HEMS operations. The AAA has begun collecting this information from member organizations, and it is envisaged that such data will progressively become more available. Two trend calculations have been performed in an attempt to validate the approximate mission numbers for the United Kingdom, but it is accepted that the true number of missions flown (and therefore the true accident rates) for this period will never be known. The calculated rates seem feasible in that they are roughly comparable with data from other countries, which are based on actual reported numbers. There is a limitation of comparing different international systems and of comparing all HEMS operations in a single country as a group. There will be variance in organizations’ standard operating procedures such as range of operations, crew composition, instrument rating of the pilot, response to primacy incidents, secondary transfers, and so on. Such variance makes it difficult to produce a national picture. This is offset to some degree by the tight regulations of the CAA such that all HEMS operations will operate according to the same overarching set of flight rules. In comparing international services, it is recognized that these flight rules may differ. The relative influence of operational differences, such as flying at night, requires further analysis but may not be substantial. For example, in 2010, of the seven fatal accidents involving HEMS aircraft in the United States, three occurred at night and four occurred during daylight hours.15 In contrast, a simulator-based study reported that instrument-proficient pilots more safely managed an unexpected encounter with instrument meteorologic conditions than those without instrument rating.16 This latter point is relevant because inadvertent requirement for instrument meteorologic conditions has been associated with an increased risk of aviation crashes.13 In the United Kingdom, HEMS operations may be changing. The change of regulations by the CAA to allow visual flight rule flights during the hours of darkness have led to some services declaring an intention to operate at night. It should be noted that the UK accident rates presented here represent a period over which no (or very few) HEMS aircraft operated at night. It should also be noted that extending flying hours would also increase the absolute number of HEMS missions flown in the United Kingdom with the associated implications to the absolute number of accidents with an accident rate similar to that of international countries already operating far more frequently. The current national picture in the United Kingdom is one of individual air ambulance services having accountability for their own operations governance, while remaining ultimately accountable to the CAA. The AAA17 is a membership body for those organizations that form part of the air ambulance services in the United Kingdom, which emphasizes the importance of close cooperation between members. The AAA operates to a code of conduct and has an important role in interservice communication and some elements of voluntary data collection but does not have any overarching regulatory or data recording capacity. In contrast, the National Police Aviation Service18 became operational in 2012 and provides centralized air support to the 43 police forces in England and
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Wales, replacing the previous structure whereby individual police forces operate their own helicopters. The National Police Aviation Service operates under a UK legal statute that requires police air support to be carried out through a single national collaboration. Centralization of this allied emergency service may provide a more unified regulatory environment, with a clearer national oversight and may facilitate important data collection and national industry communication.
CONCLUSION Accidents and serious incidents relating to HEMS operations in the United Kingdom have been comprehensively identified for the first time. This has allowed an estimation of overall accident and fatal accident rates and comparison of these rates with those of other countries’ HEMS operations. In a time of potential for the increased use of HEMS aircraft in the United Kingdom, it is essential to remain mindful of safety. This could be facilitated by the central collection of basic operational data such as mission frequency and characteristics, which will allow accident rates to be monitored and compared between services, between modes of emergency medical transport, and internationally. The use of HEMS in prehospital emergency medicine and interfaculty transfer must be considered in the context of both clinical efficacy and operational safety. AUTHORSHIP A.C. had the idea for the research and assisted with the data collection and analysis. P.H.G. assisted with the data collection and analysis. A.C., P.H.G., and T.J.H. participated in the construction, review, and revision of the manuscript. All listed authors read and approved the final manuscript submission.
ACKNOWLEDGMENT We acknowledge the helpful contribution of Professor Timothy Harris and Captain Nicola Smith in the review of key parts of the final manuscript.
DISCLOSURE The authors declare no conflicts of interest.
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