People are surprised to learn that helicopter crashes are more prevalent in Helicopter Air Medical Operations. Generally, the statistical number of incidents of injury, accident or death in 14 C.F.R.§ 121 (known as “Part 121”, or commercial passenger aviation) operations are incredibly low. There are more serious injuries and deaths resulting from helicopter air medical operations.
For example, in 2010, according to the NTSB (which is charged with investigating every aviation accident in the United States, and many abroad), there were no fatalities in any of the Part 121 accidents in 2010. This despite some 17.5 million Part 121 flight hours. Of all of the Part 121 flight hours in 2010, the most common defining event was a turbulence encounter, accounting for 26% of all Part 121 accidents in 2010.
Most of the defining events for Part 121 accidents in 2010 (just as they have been in general for the last 10 years) were events such as ground collisions, ground handling, runway incursion, cabin safety, system failure, bird strikes etc., many or most of which are ground events. More than half of the Part 121 accidents that occurred in 2010 occurred during takeoff or landing (according to NTSB data, this is generally true of Part 121 accidents every year). Less than half of Part 121 accidents in 2010 happened en route. However, the major factor in Part 121 accidents is turbulence (even though, as a cumulative total, there are more incidents during takeoff and landing than there are en route). En route, turbulence is the biggest factor in accidents because commercial airlines fly at multiples of the altitude that, for example, helicopters do.
Given the relative flying altitudes, flight durations, weather events, cruise speeds etc., involved in Part 121 operations, turbulence, as it is understood in Part 121 accidents, does not have anything to do with the relatively high incidents involved in helicopter air medical operations or helicopter accidents in general.
Interestingly, according to NTSB data, most helicopter air medical operations involving fatalities do not occur when patients are being transported. Rather, most occur when helicopters are en route to get patients or when they are transporting organs. The inference to be drawn is that, while helicopters have great pilots, those pilots are taking chances while flying that they do not take when a patient is on board.
Air medical operations are conducted under both Part 135 and Part 91, depending on whether patients are being carried on board the aircraft. Helicopter Emergency Medical Services (“HEMS”) missions en route to collect patients, or organs, or to reposition aircraft after accomplishing patient transport operations, are generally conducted under Part 91. Trips conducted to transport patients or organs on board are conducted under Part 135. Some air medical helicopter operations, particularly for emergency medical services are conducted by state or local government entities as public use flights, whether patients are on board or not.
Although fixed-wing aircraft are also used for Part 91 and Part 135 medical missions, there were only 10 fixed wing fatalities in air medical operations during the entire decade between 2000 and 2009.
A Statistical Overview of HEMS Accident Frequency and Type
HEMS accounted for about 80 percent of all air medical accidents during the ten-year period 2001-2010. Against this backdrop, we examine HEMS accidents, where in 2010 alone, there were 13 Helicopter Emergency Medicine Accidents (“HEMS”), 7 of which were fatal. http://www.ntsb.gov/doclib/reports/2012/ARA1201.pdf (at page 2) Six of the Seven HEMS fatalities in 2010 involved operations under Part 91. From 200 through 2010 (the most recent year NTSB statistics are available), 33 percent of HEMS accidents were fatal. Most HEMS accidents occurred during airborne phases of flight and during 2010, all HEMS fatalities occurred during airborne phases of flight.
Obviously this is explained in part by the fact that unlike fixed-wing air medical operations, HEMS do not generally operate out of establish aerodromes. Instead, they operate out of off-airport locations where patients are in need of timely, critical care. In every year except 2007, the number of Part 91 air medical helicopter accidents without patients aboard have been significantly higher than any other category of air medical flying. http://www.ntsb.gov/doclib/reports/2011/ARA1101.pdf (at page 23)
It may be useful to breakdown the 31 accidents involving 32 helicopters in air medical operations between 2007-2009. Eighteen were being operated under Part 91, 13 were conducted under Part 135, and one was conducted as a public use flight. Eleven of the accidents, involving 12 helicopters, were fatal. Collision with objects on takeoff or landing accounted for 7 of the 31 accidents, but no fatalities. On the other hand, four of the five controlled flight into terrain accidents were fatal, including the crash of the Maryland State Police Public use flight carrying accident victims on approach to Andrews Air Force Base. Two of the three loss of control in-flight accidents were fatal, as were two of the three unintended flights into instrument meteorological conditions accidents. The midair collision between two HEMS helicopters conducting Part 135 operations in Flagstaff, Arizona, in June 2008 was also fatal to all on board. The other two fatalities involving a non-power plant system were coded as other. http://www.ntsb.gov/doclib/reports/2011/ARA1101.pdf (at page 24)
What Are The Typical Causes?
In any aviation operation, pilot training and experience, and pilot judgment are some of the most important factors in safe flight. With helicopter operations generally, and particularly HEMS operations, pilot experience, training and judgment are even more critical because of the conditions they fly in, such as bad weather, night, rural areas where wires or other low strike points may not be lighted or marked and air-traffic may be uncontrolled. HEMS operations also face an unparalleled need for speed to save lives. Review of individual NTSB probably cause reports, NTSB factual data and other aviation industry data would tend to suggest that fatal and serious injury helicopter accidents are most often the result of a number of factors including loss of control, visibility issues, wired strikes, system component failure or post-impact fire. Although some of these issues pose dangers during Part 121 operations, they simply do not pose the same risks, largely due to obvious differences in the nature of the aviation operation, the equipment, altitude, avionics, take-off and landings from tightly controlled air-space and the use of aerodromes. In addition, HEMS operations often involve situations in which minutes may literally save life and limb, prompting hurried behavior. While that is not to suggest that HEMS pilots are not some of the best helicopter pilots flying, they do face particular challenges, to which Part 121 pilots or even fixed-wing air medical operations pilots are less exposed.
There are also tremendous swings in helicopter air medical pilot training. From 2007-2009, for example, NTSB data suggest that the accident helicopter pilots’ median age was 54, ranging from 35 to 69. Median total flight hours were 7,125 with a range from 2,685 to 18,000. The median time in the type of accident helicopter was 375 hours, ranging from 11 to 4,241. Statistics suggest that such variations in flight time and the corollary impact on experience and judgment may be significant factors in the number of crashes. http://www.ntsb.gov/doclib/reports/2011/ARA1101.pdf (at page 26). HEMS operations more often than not must use unimproved landing sites at accident scenes and helipads and hospitals or medical facilities. Loss of control in flight was the most common event for both fatal and non-fatal helicopter crashes, followed by collisions on takeoff or landing and system component failure of the power plant.
Even though HEMS pilots may have thousands of flight hours, and are unquestionably some of the best helicopter pilots in the world, owners and operators of HEMS operations should continuously emphasize the consistent causes of HEMS crashes and adapt training programs to focus on those causes.
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