US Navy Helicopter Mishap Findings & Recommendations · 2011-10-11 · 28 Birthplace, Home and Future of Aerospace Medicine • Mishaps were compared for additive risk of night operations

Birthplace, Home and Future of Aerospace Medicine

US Navy Helicopter Mishap US Navy Helicopter Mishap Findings & RecommendationsFindings & Recommendations

Lt Col Rawson WoodLt Col Rawson Wood

Lt Col Rick MooneyLt Col Rick Mooney

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Statement of AccountabilityStatement of Accountability

• This brief represents the position of the researchers. It does not represent the position of any other organization including the United States Air Force or the Department of Defense

• This study is the fourth part of a study of all U.S. DoD rotary wing mishaps

Cleared for public release by ASC Public Affairs.Disposition Date: 3 May 2007Document Number: AFRL-WS 07-1100

3


BackgroundBackground

• 393 US Navy and USMC Class A and B mishaps from safety center database, divided into 2 deciles

• Fiscal year 1985-1994 (10 years) compared to FY 1995-2005 (11 years)

• Categorized by researcher, based on mishap review, as human factors (HF) or non-HF mishap • HF mishaps involve errors made by aircrew only,

not ATC, maintenance or supervisors• Airframe types combined (UH1 = UH1J + UH1N) • Excel & Epi Info™ used for analysis

4


OverviewOverview

• Force & Mishap Characterization• Overview By Type of Platform• Mishap Rates by Type and Decile• Fatality Rates Embarked and Ashore• The Risk at Night• The Risk By Phase of Flight, Mishap Cause &

Brownout• Human Factors & Velocity• Conclusions & Recommendations

5


Force & Mishap Characterization

6


Average Annual Inventory Size Average Annual Inventory Size FY 85 FY 85 –– 0505

0

50

100

150

200

250

300

350

400

Number in Fleet

AH-1

UH-1

H-46

H-53

H-60

7


Utilization Rates,Utilization Rates,Hours per AircraftHours per Aircraft--Year, FY 85 Year, FY 85 –– 0505

0

50

100

150

200

250

300

350

400

Hours per Aircraft-Year

AH-1

UH-1

H-46

H-53

H-60

8


% of Inventory, FY 85 % of Inventory, FY 85 –– 05, Involved in 05, Involved in Class A or B HF MishapsClass A or B HF Mishaps

0

5

10

15

20

25

30

% Involved

AH-1

UH-1

H-46

H-53

H-60

9


% of Inventory, FY 85 % of Inventory, FY 85 –– 05, Involved in 05, Involved in Class A or B NHF MishapsClass A or B NHF Mishaps

0

5

10

15

20

25

30

% Involved

AH-1

UH-1

H-46

H-53

H-60

10


Overview by Type of Platform

11


AHAH--1, Cobra1, Cobra

• Models AH-1J, T, W• First flew in 1967• Fleet size

• 207 (1990)• 154 (2000)

• Class A mishaps • 14 (1985-1994) • 12 (1995-2005)

• Fatalities• 20 (1985-1994)• 10 (1995-2005)

• Injured • 14 (1985-1994)• 13 (1995-2005)

12


UHUH--1, Iroquois (Huey)1, Iroquois (Huey)• Models: UH-1D, E, J, K, N• First flew in 1967• Fleet size

• 79 (1990)• 142 (2000)

• Class A mishaps • 25 (1985-1994)• 15 (1995-2005)

• Fatalities • 63 (1985-1994)• 24 (1995-2005)

• Injured • 54 (1985-1994)• 56 (1995-2005)

13


HH--46, Sea Knight46, Sea Knight

• Models C/HH-46A, D, E• First flew in 1962• Fleet size

• 481 (1990) • 319 (2000)

• Class A mishaps• 44 (1985-1994)• 20 (1995-2005)

• Fatalities • 89 (1985-1994)• 53 (1995-2005)

• Injured • 225 (1985-1994)• 41 (1995-2005)

14


HH--53, Super Stallion53, Super Stallion

• Models: CH-53A, D, E• First flew in 1964• Fleet size

• 141 (1990)• 185 (2000)

• Class A mishaps • 26 (1985-1994)• 15 (1995-2005)

• Fatalities • 99 (1985-1994)• 48 (1995-2005)

• Injured • 138 (1985-1994)• 43 (1995-2005)

15


HH--60, 60, SeaHawkSeaHawk

• SH-60B/F, UH-60L, VH-60N, HH-60H, others

• First flew in 1974• Fleet size

• 237 (1990)• 276 (2000)

• Class A mishaps • 15 (1985-1994)• 21 (1995-2005)

• Fatalities • 12 (1985-1994) • 24 (1995-2005)

• Injured • 21 (1985-1994)• 59 (1995-2005)

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Mishap Rates by Type and Decile

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U.S. Navy Helicopter Class A Mishap U.S. Navy Helicopter Class A Mishap RatesRates

0

1

2

3

4

5

6

7

AH-1 UH-1 H-46 H-53 H-60

Airframe

Cla

ss A

Mis

hap/

100k

Hrs

1985-19941995-2005

18


Class A Mishap Rate by Decile Class A Mishap Rate by Decile (1(1stst Decile compared to 2Decile compared to 2ndnd))

0.3850.66 - 2.711.34H-60

0.1970.77 - 3.001.51H-53

0.032*1.01 – 3.141.78H-46

0.6160.42 – 1.700.85UH1

0.1480.76 – 4.281.79AH1

P95% CIRR

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U.S Navy Helicopter Mishap Fatality U.S Navy Helicopter Mishap Fatality RatesRates

0

2

4

6

8

10

12

14

16

AH-1 UH-1 H-46 H-53 H-60

Airframe

Fata

litie

s/10

0K H

rs

1985-19941995-2005

20


Fatality Rate by Decile Fatality Rate by Decile (1(1stst Decile compared to 2Decile compared to 2ndnd))

0.860.44 - 1.960.94H-60

0.00068*1.26 - 2.581.80H-53

0.029*1.02 – 2.071.46H-46

0.120.89 - 2.391.45UH1

0.0026*1.35 – 6.943.03AH1

P95% CIRR

21


Injury Rate by Decile Injury Rate by Decile (1(1stst Decile compared to 2Decile compared to 2ndnd))

0.1100.39 - 1.120.67H-60

0.000*1.97 - 4.012.80H-53

0.000*3.37 – 6.734.76H-46

0.8250.65 – 1.420.96UH1

0.1980.73 – 3.691.63AH1

P95% CIRR

22


Fatality Rates Embarked & Ashore

23


EmbarkedEmbarked

24


U.S. Navy Helicopter Mishap Fatality Rate U.S. Navy Helicopter Mishap Fatality Rate 1985 1985 --19941994

0

10

20

30

40

50

60

70

AH-1 UH-1 H-46 H-53 H-60

Airframe

Fata

litie

s/10

0k H

rs

Ashore

At Sea

25


U.S. Navy Helicopter Mishap Fatality Rate U.S. Navy Helicopter Mishap Fatality Rate 19951995--20052005

0

5

10

15

20

25

30

35

40

AH-1 UH-1 H-46 H-53 H-60

Airframe

Fata

litie

s pe

r 100

k H

ours

Ashore

At Sea

26


Fatality Rate, Fatality Rate, Embarked compared to AshoreEmbarked compared to Ashore

0.0000*2.72 - 12.035.68H-60

0.0000*2.53 - 5.553.76H-53

0.0000*6.64 – 13.759.55H-46

0.0000*2.19 – 5.813.58UH1

0.00004*1.90 – 10.904.62AH1

P95% CIRR

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The Risk at Night

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• Mishaps were compared for additive risk of night operations and no increased risk was identified with the exception of UH-1 operations in the first decile

• UH-1 first decile night operations showed 2.51 times the relative risk of day operations for a mishap 95% CI (1.1-5.71) p = .024

• Second decile UH-1 night operations had no increased risk

The Risk at Night

29


The Risk by Phase of Flight, Mishap Cause & Brownout

USN Helicopter Fatalities & Injuries USN Helicopter Fatalities & Injuries by Phase Of Flightby Phase Of Flight

0 200 400 600 800

Cruise

T/O &G/A

Hover &Taxi

Landing

UninjuredInjuredFatal

31


Mishap Causes 1985 Mishap Causes 1985 -- 19941994

Engine

Tail Rotor

Unknown

Fire/other

HF-Midair

HF-CFIT

HF-Other

32


Mishap Causes 1995 Mishap Causes 1995 -- 20052005

Engine

Tail Rotor

Unknown

Fire/other

HF-Midair

HF-CFIT

HF-Other

33


Brownout Rates (/100K Hours)Brownout Rates (/100K Hours)

0

0.05

0.1

0.15

0.2

0.25

0.3

AH-1UH-1H-46H-53H-60

34


Human Factor vs. Non-Human Factor Mishaps

Fatality Rates/100K HoursFatality Rates/100K Hoursby HF and Nonby HF and Non--HF By MDSHF By MDS

0

2

4

6

8

10

12

AH-1 UH-1 H-46 H-53 H-60

Non-HF

HF

FY 85 - 05

Class A Mishap Rates/100K HoursClass A Mishap Rates/100K Hoursby HF and Nonby HF and Non--HF By MDSHF By MDS

0

0.5

1

1.5

2

2.5

3

3.5

AH-1 UH-1 H-46 H-53 H-60

Non-HF

HF

FY 85 - 05

37


Human Factors and Velocity

38


Human Factors Numerator DataHuman Factors Numerator Data

14 (14)17 (3)4 (4)4 (3)9 (2)3 (2)7 (3)Total

1 (8)1 (2)0 (1)0 (1)0 (1)0 (1)0 (0)H-60

2 (1) 4 (0)1 (0)1 (0)4 (1)0 (0)1 (0)H-53

4 (1)10 (1)2 (2)1 (1) 3 (0)1 (0)2 (1) H-46

4 (3)2 (0)1 (1) 0 (1)1 (0)1 (1) 2 (0)UH1

3 (1)0 (0)0 (0)2 (0)1 (0)1 (0)2 (2)AH1

CFITRotorStrike

PowerLine

SpatialDisorientation

VMC-IMCBrownoutMidairAirframe

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USN Helicopter HF MishapsUSN Helicopter HF MishapsFatality Rate/100K Hours Fatality Rate/100K Hours -- Low Speed vs. High SpeedLow Speed vs. High Speed

0

1

2

3

4

5

6

7

AH-1 UH-1 H-46 H-53 H-60

Low SpeedHigh Speed

40


USN Helicopter NHF MishapsUSN Helicopter NHF MishapsFatality Rate/100K Hours Fatality Rate/100K Hours -- Low Speed vs. High SpeedLow Speed vs. High Speed

00.20.40.60.8

11.21.41.61.8

2

AH-1 UH-1 H-46 H-53 H-60

Low SpeedHigh Speed

41


Conclusions & Recommendations

42


DiscussionDiscussion• Embarked operations: potential for “softer” water impact with

less obstacles, but data shows statistically significant increased fatality rates than in operations ashore (Drowning)

• Hover and ground ops less fatal than cruise operations (matches USAF & Army Data) - Due to V2

• Newer airframes look safer than older• Statistically significant improvements in fatality and injury rates

occurred across the AH-1, H-46 & H-53 airframes in the second decile!

• Only the H-46 achieved a statistically significant reduction in mishap rate in the second decile: RR 0.56 – 95%CI (.33 - .96) p = 0.0325

• Unlike the USAF and Army data, in the second decile, night operations impose no statistically significant increase in mishap rates compared to day operations

43


ConclusionsConclusions

• Rotary Wing operations have higher mishap rates than fixed-wing operations

• Embarked operations have higher Class A mishap and fatality rates than shore operations

• The cruise phase of flight has a higher mortality than other phases of flight (V2 Wins)

44


ConclusionsConclusions• USN database lacks data to conduct detailed analysis

• Number of airframes in fleet (obtained from civil sources)

• Number of night, NVG, IMC hours flown (estimated from pilot records)

• Number of hours flown over land versus embarked (not recorded – could MFOQA get this data?)

• Weather conditions at time/location of mishap (weather often discussed only if factor)

• Database not standardized with other services

• HFACS may improve this situation

45


RecommendationsRecommendations

• Track morbidity and mortality in addition to mishap rate information

• Improve and standardize mishap database to capture numerator and denominator data needed for analysis

• Establish a DoD center for analysis to standardize data collection throughout the Services and conduct analysis of systems used by more than one service

Documents

US Navy Helicopter Mishap Findings & Recommendations · 2011-10-11 · 28 Birthplace, Home and Future of Aerospace Medicine • Mishaps were compared for additive risk of night operations