US HEMS Accident Rates 2006-2015

The safety of US Helicopter Emergency Medical Service (HEMS) operations has been a topic we have discussed previously.  With HeliExpo approaching, when 10 years of the International Helicopter Safety Team (IHST) will be marked and with US NTSB Board Member Robert Sumwalt just publishing a HEMS article in Professional Pilot, we thought we’d take a look at how the US HEMS accident rates have changed over the last decade.

US HEMS Accident Data

Sumwalt helpfully tabulates ten years of accidents (reproduced at the bottom of this page). With 90 deaths and 93 helicopters lost in 92 accidents (one was a mid air collision), Sumwalt notes there has been an accident every 40 days on average. We have converted that into a graph and added 3 year moving averages to better examine the trends (unfortunately HEMS flying hours data is not readily available to refine the data).

us hems accident rates

US HEMS Safety Analysis

Accidents: The 3 year moving average has dropped 33% from 12 to 8 per annum, though it seems to have plateaued over the last 5 years.  In 2015 there were 7 accidents (22% less than the 10 year average).

Fatal Accidents: The 3 year moving average finishes as it started at 4, though the 3 year moving average peaked in 2011 at 7 (due to 12 fatal accidents in 2010).  There has been negligible change in the last 4 years. In 2015 there were 5 fatal accidents (14% more than the 10 year average).

Fatalities: The 3 year moving average has dropped 33% from 13 to 9 per annum, though it seems to have plateaued over the last 5 years. In 2015 there were 9 fatalities (identical to the 10 year average).

US HEMS Accident Trend – Where Next?

As Sumwalt highlights, new long awaited Federal Aviation Administration (FAA) regulation changes are coming into effect.

On 20 February 2014, the FAA) issued an extensive package of changes to Parts 91, 120 and 135 (following the spike in fatal accidents and fatalities in 2013).  This followed proposals in late 2010 (6 years after a specific FAA Task Force was originally created) and the year after the NTSB held a 2009 public hearing on HEMS (triggered by the 20 fatalities in 2008) and issued a series of safety recommendations.

But will they spark a noticeable downward trend?  Well, maybe.  Some of the safety benefit should have already been gained by the enthusiastic early adopters, so the improvement from late, unenthusiastic operators is unlikely to be huge.

A recent voluntary industry commitment to Crash Resistant Fuel Systems (CFRS) on older aircraft without the benefit of a CRFS should have an effect on fatalities and on the stubborn fatal accidents rate per annum.  However that benefit is by is very nature balanced by the continued operation of aircraft certified in the early 1990s or earlier.

Any wider adoption of the various safety initiatives that Sumwalt mentions, including wider implementation and maturity of Safety Management Systems, plus more capable, modern aircraft should also have a positive effect but only time will tell if the industry acts in a concerted way.

UPDATE 24 December 2016: Dr Ira Blumen, program/medical director for the University of Chicago’s Aeromedical Network (UCAN) has been tracking US HEMS safety performance since 2000. A recent report based on his data noted:

In 1980, a HEMS crewmember had a 1 in 50 chance of being in a fatal accident; today that number is 1:850. 

From 1972 to 2016 there were 342 helicopter EMS accidents…123 of those 342 resulted in at least one fatality. Some 1,053 personnel were involved in those accidents; 328 died, 116 sustained serious injuries, 136 had minor injuries and 473 were uninjured… [meaning] 68.8 percent survived

Unfettered competition has allowed the nation’s HEMS fleet to mushroom from 151 aircraft in 1986 to 309 in 1996 to 648 in 2006 to 852 today. If you add in dual-purpose aircraft, the number is 979, and it could be as high as 1,048 if you count non-operational spares. [However] “This is the first year ever there has been a contraction in the number of helicopters,” Blumen said. 

…the average aircraft flew 800 hours in 1994 and 600 hours between 2003 and 2008, at which time flying dropped precipitously after the accidents of 2008 and the ensuing negative publicity.  “People said, ‘We are not sending our patients in helicopters,’” Blumen noted. Now the number of flight hours per helicopter is moving up again, averaging 490 in 2016.

Extra Resources

See our previous articles:

We have also plotted data for accident rates in Gulf of Mexico (GOM) oil and gas operations.

Aerossurance has extensive helicopter safety, airworthiness, operations, assurance and accident analysis experience.  For aviation advice you can trust, contact us at:

US HEMS Accidents (Credit: NTSB)

US HEMS Accidents (Credit: NTSB)