Transcript Slide 1
Why do business aircraft go off the
runway more often than commercial
aircraft?
Gerard van Es
58th annual Business Aviation Safety Seminar
Montreal, Canada
April, 2013
What is a runway excursion?
A veeroff or overrun off the
runway surface during takeoff or landing
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Do business aircraft go off the runway
more often?
Runway excursion rate per million flights
4
Business
3.5
Commercial
3
2.5
2
1.5
1
0.5
0
Y2010
Y2011
Y2012
Worldwide data, accidents & incidents
Source: NLR-ATSI
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Runway excursion accident rate
ICAO Annex 13 Accident Rate
1980-2008
Commercial
Business
0
0.5
1
1.5
Rate per million flights
2
2.5
Source: NLR-ATSI
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Is runway excursion risk important
for business aviation?
35% of all take-off & landing accidents with business ops
involved a runway excursion;
Can result in fatalities and/or significant damage to a/c;
In top 6 of NTSB Priorities on Business Aviation safety.
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Some accident/incident data analysis
Source: NLR-ATSI Air Safety Database
Inclusion criteria:
– Runway excursions with known causes;
– Period 1980-2010;
– Worldwide;
– Single engine aircraft excluded;
– Turbine/turboprop aircraft.
>1600 excursions met these criteria.
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Flight phase and excursion type
Type
Phase
Business
Commercial
Aircraft overrun
Landing
38%
39%
Aircraft overrun
Take-off
10%
12%
Veeroff
Landing
36%
39%
Veeroff
Take-off
16%
10%
Source: NLR-ATSI
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Top factors in runway excursions
wet/contaminted rwy
Long flare
Fast approach/TD
Crosswind
System failure
Commercial
Business
Tailwind
Incorrect use of stopping devices
Tire failure
Aquaplaning
Abort/reject - After V1
Hard land
Percentage of all excursions with known factors
High on approach
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
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Exposure to risk factors
Similar distribution of top causal factors between business
and commercial operations;
Difference in exposure to risk factors?
– Knowledge of day to day operations needed;
– Based on FDM/FOQA data;
– Focus on landing.
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Wet/contaminated runway operations
Reduction runway friction;
No good data on number of business operations on
wet/contaminated runways;
Business a/c can operate at smaller airports:
• Runway surface condition monitoring less sophisticated;
• Less equipment for snow removal.
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Unstabilised approaches
Influence on fast & high approaches;
Comparison typical rates:
– Commercial operations: 1-8% of all approaches;
– Business operations: 1-14% of all approaches;
Go-around rates following unstabilised approaches are low:
– Only 1-2 % of unstabilised approaches resulted in a goaround;
– Higher values in commercial ops.
Source: NLR-ATSI/FSF
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Fast approaches
Speed difference at threshold (VTH – Vapp )>15 kts;
3-5 times more likely on business a/c operations.
Source: NLR-ATSI
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Long flare (long landing, deep landing)
Rate of landings >2,400 ft touchdown from threshold
Business
8 Times more likely on business ops
Commercial
0%
5%
10%
15%
20%
Source: NLR-ATSI
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Tailwind operations
35%
More tailwind landings in business ops
30%
25%
Commercial
Business
20%
15%
10%
5%
0%
Tailwind Kt.
Headwind Kt.
Source: NLR-ATSI/FSF
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Runway length in overruns occurrences
Average runway length (m)
TO-Passenger/cargo
A/c type depended
TO-Business
No data on day-to-day ops
LA-Passenger/cargo
LA-Business
0
1000
2000
3000
Source: NLR-ATSI
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Landing distance assessment
Issues with landing distance assessments at time of arrival:
– Not always required by operator (dispatch assessment
only);
– Confusion on whether reverse thrust has been included;
– Sometimes based on (un)factored AFM instead of realistic
landing performance data;
– No (good) data for contaminated runways;
– No guidance on how to use actual operational landing
distance information;
– No safety factors applied.
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Runway width in veeroffs occurrences
Average runway width (m)
Commercial
Matches with runways normally used
Business
0.0
10.0
20.0
30.0
40.0
50.0
Source: NLR-ATSI
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Wheel track comparison
Commercial a/c
Business a/c
5-14 m
2.5-6 m
Maximum allowable deviation from centerline is 9.1
m;
VMCG and X-wind adjustments could be needed on
narrow rwys (not common on business a/c).
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Demonstrated crosswinds (dry rwy)
50
Business Jets
45
Passenger aircraft
Crosswind (kts)
40
35
30
25
20
15
Buss Jets average: 26 kts
10
5
0
1950
Passenger a/c average: 30 kts.
1960
1970
1980
1990
Year of certification
2000
2010
2020
Source: NLR-ATSI
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Crosswind and contaminated runways
Not part of certification – advisory only;
Advisory material normally available for commercial a/c:
– But not perfect!
Often limited advisory material for business a/c, e.g.:
– Only for an icy runway;
– Statements like “extreme care should be taken...”, no hard
numbers;
– Crosswind limits based on non-validated correlation with
runway friction coefficient.
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How to manage the risk?
Check out the different initiatives and tools, e.g.:
European Action Plan for the Prevention of Runway
Excursions (EAPPRE);
IATA/FSF Runway Excursion Risk Reduction (RERR) Toolkit;
FSF - Runway Excursion Risk Awareness Tool:
– Can be used during dispatch.
FSF - ALAR toolkit;
Guidance material from NBAA.
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Remember there is more than factor
causing runway excursions
Example
Excess approach speed,
Late touchdown,
Delayed application wheel brakes.
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Conclusions
Runway excursion causes are the same for business and
commercial aircraft;
Exposure to certain risk factors is often higher during
business operations:
–
–
–
–
Unstabilised approaches;
Long landings;
Fast landings;
High tailwind landings.
Less guidance for operations on contaminated runways for
business a/c;
Lack of FDM/FOQA data for business operations (less
awareness of rwy excursion risk factors).
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It can happen more than once....
SANTOS DUMONT AIRPORT, Brazil
Landing overrun
Take-off overrun
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