1. U.S. Rotorcraft Accident Data and Statistics
Presented to: FAA/Industry Safety Forum
By: Lee Roskop, Operations Research Analyst
Date: Jan 2012

2. U.S. Registered Rotorcraft Accidents 30 Year History: 1982-2011

3. U.S. Registered Rotorcraft Accidents Focus on 10 Year History: 2001-2010

4. Progressing from accident totals to accident rates requires flight hours.
The FAA’s General Aviation and Part 135 Activity Survey is the source for U.S. rotorcraft flight hour estimates used calculations used in this presentation.

5. U.S. Registered Rotorcraft Accidents Estimated Accident Rates: 2001-2010

6. U.S. Registered Rotorcraft Accidents Estimated Accident Rates: 2001-2010
Start of IHST initiative and goal to
reduce accident rate 80% in 10 years
2006 – 2010: IHST was analysis centered
2011 – 2015: IHST is implementation centered
IHST’s goal is a rate of 1.8 by 2016. *

7. What are the usual environmental conditions for rotorcraft accidents?
Based on NTSB data for U.S. rotorcraft accidents from :
Over 88% occur in daylight conditions
Over 95% occur in VMC

8. What industry sectors result in the most rotorcraft accidents?
Helicopter EMS?

9. What industry sectors result in the most rotorcraft accidents?
Helicopter EMS?
Air Tour?

10. What industry sectors result in the most rotorcraft accidents?
Helicopter EMS?
Air Tour?
Offshore?

11. What industry sectors result in the most rotorcraft accidents?
Helicopter EMS?
Air Tour?
Offshore?

12. Rotorcraft Accidents by NTSB Classification 10 Years from CY01 to CY10 – 1,672 Accidents
External Load 1.9%
6 Other Categories 1.5%
Aerial Observation 3.3%
Flight Test 1.4%
Business 4.7%
Positioning 4.9%
Instruction/Training 21.7%
Other Work 7.4%
EMS 7.8%
Personal/Private 20.0%
Aerial Application – purpose of flight is Part 137 operations, typically involves spraying/disbursing a product such as pesticide or fertilizer
Aerial Observation – purpose of flight may be varied, from photography/filming, fish/game spotting, property review, oil and mineral exploration, or traffic monitoring
Business – support of internal company operations without a paid, professional crew. May include pax transport but not Part 135 “for hire” operations.
EMS – Part 91 or Part 135 medical flight
External Load – Part 133 operations
Flight Test – Maintenance or testing on aircraft
Instruction/Training – either dual instruction, solo student flight, or pilot checkride
Not Categorized – whether intentionally or by omission, the NTSB did not categorize the flight
Other Work – a miscellaneous category that can includes a diverse set of operations to include aerial demonstration, utilities patrol, aerial advertising, livestock herding, or sightseeing
Personal/Private – Part 91 operation in support of no particular operation other than the operators desire to fly
Positioning – movement of the aircraft from one location to another for another mission
Public Use – public aircraft status at time of accident, typically in support of a law enforcement agency such as police, sheriff, or border patrol, but also includes agencies such as the forest service
Public Use 7.8%
Aerial Application 8.2%
Not Categorized 9.3%

13. IHST’s Analysis of U.S. Accidents CYs 2000, 2001, 2006 – 523 accidents
Electronic News Gathering 1.7%
Personal/Private 18.5%
Utilities Patrol/Construction 2.1%
External Load 2.7%
Logging 2.7%
Instruction/Training 17.6%
Firefighting 3.6%
Offshore 4.2%
Aerial Observation 4.2%
Business 4.8%
Aerial Application 10.3%
Air Tour / Sightseeing 5.9%
Emergency Medical Services 7.6%
Law Enforcement 6.5%
Commercial 7.5%

14. 2011 Analysis of U.S. Accidents
Offshore 0.8%
Firefighting 0.8%
Business 1.6%
Personal/Private 27.6%
Air Tour / Sightseeing 1.6%
Utilities Patrol/Construction 2.4%
External Load 2.4%
Law Enforcement 3.1%
Aerial Observation 4.7%
Instruction/Training 18.9%
Emergency Medical Services 6.3%
Commercial 11.0%
Aerial Application 18.9%

15. Hopefully the last few slides left you with a better impression than this…
…but percentage of accidents within each industry sector is only half of the story.

16. Personal/Private Accidents Compared to Flight Hours
The tragedy of personal/private helicopter operations: low volume of flight hours results in a high volume of accidents.
As evident, the number of helicopter accidents in the personal/private category is not at all proportionate to the number of flight hours flown. In fact, there is a stunningly large gap between the low percentage of U.S. helicopters hours flown in personal/private operations as compared to the high percentage of U.S. helicopter accidents. The bottom line in the comparison is that for the 10 years analyzed, the personal/private category accounted for only about 5% of U.S. helicopter hours flown yet resulted in about 20% of the helicopter accidents.

17. Instruction/Training Accidents Compared to Flight Hours
Instruction/Training has a similar problem to Personal/Private: a higher percentage of rotorcraft accidents as compared to rotorcraft hours flown. It does seem that the gap has closed some since 2006, but there are still years since then where large spikes occur. While the gap is not as large nor as consistent as what is seen with Personal/Private, the problem is still there.

18. Aerial Application Accidents Compared to Flight Hours
Same as the personal/private and instruction training: percentage of accidents is high relative to flight hour exposure. The concerning aspect of the Aerial Application chart is the trend the last 3-4 years. The gap between the two lines is getting larger. Though we do not yet have the estimated CY2011 flight hours, we do know that aerial application accounted for about 20% of the accidents in 2011 and it is likely that the percentage of rotorcraft hours is comparable to the historical norms of about 5%. That would be a second consecutive year with a delta of about 15%. Again, affirmation of a trend moving in the wrong direction.

19. HEMS Accidents Compared to Flight Hours
This slide really is for comparison purposes. HEMS accidents have been closely scrutinized leading to focused manpower and resources devoted to safety improvements. Yet, notice how historically over the last 10 years how HEMS has consistently had a LOWER percentage of rotorcraft accidents relative to the percentage of rotorcraft hours flown. Contrast this what we just saw on the slides for personal/private as well as instruction/training and aerial application.
Using estimated flight hours as well as accidents for personal/private and HEMS, we can generate 10 Year ( ) comparative accident rates truly illustrate the magnitude of the personal/private problem. HEMS rate (per 100,000 flight hours) is 3.9 compared personal/private at 29.6.

20. Accident rate comparison
HEMS 2001 – 2010
3.9 accidents per 100,000 flight hours

21. Accident rate comparison
HEMS 2001 – 2010
3.9 accidents per 100,000 flight hours
Personal/Private 2001 – 2010
29.6 accidents per 100,000 flight hours
Over 7 Times Higher than Helicopter EMS

22. Another approach to examining rotorcraft accident trends: Cro Amsaa

23. Cro Amsaa?
…is not this (Cro Magnon).

24. Cro Amsaa
…is not this (Cro Magnon).
…but is this!

25. Cro Amsaa Analysis
In this model, each accident constitutes a “system failure”. We keep a cumulative count of system failures and plot those against an elapsed number of calendar days. The plot shown is entirely independent of flight hours.

26. Cro Amsaa Analysis
The value of Beta tells a story about the safety of our system
If Beta = 1: safety of the system is not changing
If Beta > 1: failures occurring faster
If Beta < 1: failures occurring slower
All Accidents CY
The Beta value from is less than 1, indicating a system where safety is improving.
The Beta value from is also below 1, but is lower than the overall Beta from This is an indicator of improved safety in the system during the time frame.
All Accidents CY
All Accidents CY

27. Cro Amsaa Analysis Bottom line:
Overall, the safety of our system got slightly better from 2001 to 2010.
Comparatively,
2001 to 2005: system safety was stagnant to slightly deteriorating
2006 to 2010: system safety was improving
All Accidents CY
The Beta value from is less than 1, indicating a system where safety is improving.
The Beta value from is also below 1, but is lower than the overall Beta from This is an indicator of improved safety in the system during the time frame.
All Accidents CY
All Accidents CY

28. Cro Amsaa – All Rotorcraft Accidents
Our Mean Time Between Failure (MTBF) offers further confirmation of a system that is trending toward better safety the last 5 years:
Note the increase in the MTBF for 2006 to 2010 in comparison to 2001 to 2005.
All Accidents CY
All Accidents CY
All Accidents CY

29. Cro Amsaa - Only Personal/Private
Personal/Private Accidents CY
Personal/Private Accidents CY
Personal/Private Accidents CY

30. Cro Amsaa - Only Personal/Private
Although the Personal/Private sector improved from 2006 to 2010, the sector still lags behind the beta of the overall system for every block of years examined.
Beta values of overall system during same block of years
Personal/Private Accidents CY
0.938
Personal/Private Accidents CY
1.026
Personal/Private Accidents CY
0.849

31. Cro Amsaa - Only Personal/Private
Using MTBF as a measurement, Personal/Private improved from 2006 to 2010 as compared to 2001 to 2005.
Personal/Private Accidents CY 01 – 10c
Personal/Private Accidents CY
Personal/Private Accidents CY

32. Cro Amsaa - Only Personal/Private
The Personal/Private MTBF did improve by 2.5 days from 2006 to 2010 as compared to 2001 to 2005.
But the MTBFs don’t compare favorably to other industry sectors, e.g. HEMS.
Personal/Private Accidents CY
HEMS MTBF CY 01 – 10:
30.23
Personal/Private Accidents CY
HEMS MTBF CY 01 – 05:
25.05
Personal/Private Accidents CY
HEMS MTBF CY 06 – 10:
31.35

33. Gathering data on U.S. rotorcraft can be difficult, but we’re not so desperate that we’ve resorted to this technique yet.

34. What do we know about Personal/Private rotorcraft accidents?
The IHST’s study of 523 U.S. accidents across 3 years provides the most complete analysis of:
What happened (Occurrence Categories)
Why it happened (Problem Statements)
How it could have been prevented (Intervention Recommendations)
The next several slides will look specifically at these areas for the 97 Personal/Private accidents (18.5% of the 523 total accidents) in the IHST’s U.S. data set.

35. Personal/Private Accidents: Occurrence Categories tell “What happened

36. Personal/Private Accidents: More about “Loss of Control”
Loss of control occurrences were further divided into more specific sub-areas.
For Personal/Private, the Loss of Control sub-areas most frequently cited were (in descending order):
Performance Management
Exceeded Operating Limits
Lost Tail Rotor Authority

37. Personal/Private Accidents: Problem Statements tell “Why did it happen

38. Personal/Private Accidents: Problem Statements tell “Why did it happen
For purposes of this presentation we will take a closer look at just a couple of the problem statements.

39. Personal/Private Accidents: Further details for selected problem statements
“Pilot Judgment & Actions” problems most frequently occurred in the following sub-areas:
Decision Making, Landing Procedures, Procedure Implementation, Flight Profile
“Pilot Situational Awareness” problems most frequently occurred in the following sub-areas:
Awareness of External Environment, Awareness of Visibility/Weather, Awareness of Internal Aircraft Issues
Decision Making
Pilot disregarded cues that should have led to termination of the current action or maneuver
Willful disregard for rules and Standard Operating Procedures
Pilot misjudged own limitations/capabilities
Landing Procedures
Forced landing situation where pilot had problems landing from an autorotation
Selection of an inappropriate landing site
Procedure Implementation
Pilot control/handling deficiency of the aircraft
Inappropriate energy/power management
Flight Profile
Pilot selected an unsafe altitude
Pilot selected a profile that required an unsafe power margin

40. Personal/Private Accidents: Intervention Recommendations tell “How it could have been prevented”
Top 4 “Training/Instructional”
Basic Training
Safety Training
Advanced Maneuver Training
Aircraft Make and Model Transition Training
Inflight Power/Energy Management Training
Enhanced Aircraft Performance & Limitations Training
Training emphasis for maintaining awareness of cues critical to safe flight
Flight training on common operational pilot errors
Autorotation Training Program
Simulator Training - Advanced Maneuvers
Model specific transition training
Specialized training for pilots migrating from fixed to rotor wing aircraft

41. Personal/Private Accidents: Intervention Recommendations tell “How it could have been prevented”
For purposes of this presentation we will take a closer look at only Systems and Equipment recommendations.
Top 4 “Training/Instructional”
Basic Training
Safety Training
Advanced Maneuver Training
Aircraft Make and Model Transition Training
Inflight Power/Energy Management Training
Enhanced Aircraft Performance & Limitations Training
Training emphasis for maintaining awareness of cues critical to safe flight
Flight training on common operational pilot errors
Autorotation Training Program
Simulator Training - Advanced Maneuvers
Model specific transition training
Specialized training for pilots migrating from fixed to rotor wing aircraft

42. Personal/Private Accidents: A closer look at the top “Systems and Equipment” intervention recommendations
Post Incident Survivability
Crash resistant fuel systems
Install Wire Strike Protection System
Improve helicopter specific ELT practices/standards
Situational Awareness Enhancers
Install proximity detection system
Wire detection system for low altitude operations
Cockpit Indication/Warning
Automate carburetor anti-ice function or early warning alert
Fuel system status

43. The first recorded incident of a pilot choosing to ignore statistical data at the risk of his crew and passengers happened a long time ago…

44. …in a galaxy far, far away.
But sir, the possibility of successfully navigating an asteroid field is approximately 3,720 to 1!!
Never tell me the odds!!

45. What do we know about Instructional/Training Accidents?
Second highest number of accidents of any industry sector studied by the IHST’s review of U.S. helicopter accidents
92 accidents in Instructional Training
17.6% of the 523 total accidents studied

46. Instructional/Training Accidents: Occurrence Categories tell “What happened?”

47. Instructional/Training Accidents: More about “Loss of Control”
Loss of control occurrences were further divided into more specific sub-areas.
For Instructional/Training, the Loss of Control sub-areas most frequently cited were (in descending order):
Performance Management
Interference with Controls
Dynamic Rollover

48. Instructional/Training Accidents: Problem Statements tell “Why did it happen?”

49. Instructional/Training Accidents: Problem Statements tell “Why did it happen?”
For purposes of this presentation we will take a closer look at just a couple of the problem statements.

50. Instructional/Training Accidents: Further details for selected problem statements
“Pilot Judgment & Actions” problems most frequently occurred in the following sub-areas:
Procedure Implementation, Landing Procedures, Crew Resource Management, Decision Making
“Pilot Situational Awareness” problems most frequently occurred in the following sub-areas:
Awareness of External Environment
Decision Making
Pilot disregarded cues that should have led to termination of the current action or maneuver
Willful disregard for rules and Standard Operating Procedures
Pilot misjudged own limitations/capabilities
Landing Procedures
Forced landing situation where pilot had problems landing from an autorotation
Selection of an inappropriate landing site
Procedure Implementation
Pilot control/handling deficiency of the aircraft
Inappropriate energy/power management
Flight Profile
Pilot selected an unsafe altitude
Pilot selected a profile that required an unsafe power margin

51. Instructional/Training Accidents: Intervention Recommendations tell “How it could have been prevented”

52. Instructional/Training Accidents: Intervention Recommendations tell “How it could have been prevented”
For purposes of this presentation we will take a closer look at only Systems and Equipment recommendations.

53. Instructional/Training Accidents: A closer look at the top “Systems and Equipment” intervention recommendations
Post Incident Survivability
Crash resistant fuel systems
Install Wire Strike Protection System
Cockpit Warning/Indication
Install low rotor warning
Provide power available versus power required indicator
Low airspeed indicator warning
Situational Awareness Enhancers
Wire detection system for low altitude operations
Automatic hover recovery system
Proximity detection system

54. The IHST study of U.S. rotorcraft accidents went quite a bit deeper than this.

55. What do we know about Aerial Application Accidents?
Third highest number of accidents of any industry sector studied by the IHST’s review of U.S. helicopter accidents.
54 accidents in Aerial Application
10.3% of the 523 total accidents studied
Despite trailing Personal/Private and Instructional/Training in the IHST study’s percentage of total accidents, concerns in this industry sector are growing.

56. Percentage of Aerial Application Helicopter Accidents – Last 5 Years

57. Percentage of Aerial Application Helicopter Accidents – Last 5 Years
Percentages the last 2 years are comparable to Personal/Private. Also, like Personal/Private, the flight hour exposure level is relatively low.

58. Knowing when U.S. Aerial Application rotorcraft accidents are more likely to occur does not require much guessing…

59. Aerial Application Accidents by Month: 10 years from 2001-2010

60. Aerial Application Accidents by Month: 10 years from 2001-2010
76% of accidents during 6 month peak U.S. growing season of May - Sep

61. Future challenges – what to do now?
Personal/Private, Instructional/Training, and Aerial Application pose unique problems
Difficult population of operators to reach
Not likely to attend major industry or government safety forums
Less awareness/exposure to industry-wide safety initiatives and best practices
Small fleet sizes, often just 1 aircraft
Have to convince them of the benefits to make any change
Must be low cost or no cost
Must make the case that it will show immediate results

62. The goals set by the rotorcraft community for reductions in U. S
The goals set by the rotorcraft community for reductions in U.S. rotorcraft accidents will require no higher than single digit annual accident totals in each industry sector of Personal/Private, Instructional/Training, and Aerial Application.

63. This is where we stood at the end of 2011:
The goals set by the rotorcraft community for reductions in U.S. rotorcraft accidents will require no higher than single digit annual accident totals in each industry sector of Personal/Private, Instructional/Training, and Aerial Application.
This is where we stood at the end of 2011:
Personal/Private: accidents
Instructional/Training: accidents
Aerial Application: accidents
So, there is some work to be done.

64. Difficult problems sometimes lead to a new level of cooperation and innovation to find a solution….

65. Difficult problems sometimes lead to a new level of cooperation and innovation to find a solution….
…the results may surprise everyone.

66. If you found the portions of this presentation that referenced the work by the IHST useful, please go to the following address for more information, including detailed analysis reports:

67. Questions?