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?
2
A veeroff or overrun off the
runway surface during takeoff or landing
Do business aircraft go off the runway more often?
3
0
0.5
1
1.5
2
2.5
3
3.5
4
Y2010 Y2011 Y2012
Business
Commercial
Runway excursion rate per million flights
Worldwide data, accidents & incidents
Source: NLR-ATSI
Business
Commercial
0 0.5 1 1.5 2 2.5
ICAO Annex 13 Accident Rate1980-2008
Rate per million flights
Runway excursion accident rate
4
Difference is getting sm
aller last 5 yrs
Source: NLR-ATSI
Is runway excursion risk importantfor 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.
5
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.
6
Flight phase and excursion type
7
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
Top factors in runway excursions
8
0% 5% 10% 15% 20% 25% 30% 35% 40% 45%
High on approach
Hard land
Abort/reject - After V1
Aquaplaning
Tire failure
Incorrect use of stopping devices
Tailwind
System failure
Crosswind
Fast approach/TD
Long flare
wet/contaminted rwy
CommercialBusiness
Percentage of all excursions with known factors
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.
9
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.
10
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 go-around;
– Higher values in commercial ops. 11
Source: NLR-ATSI/FSF
Fast approaches
Speed difference at threshold (VTH – Vapp )>15 kts;
3-5 times more likely on business a/c operations.
12
Source: NLR-ATSI
Long flare (long landing, deep landing)
Rate of landings >2,400 ft touchdown from threshold
13
Commercial
Business
0% 2% 4% 6% 8% 10% 12% 14% 16% 18% 20%
Source: NLR-ATSI
8 Times more likely on business ops
-20 ─ -15
-15 ─ -10
-10 ─ -5
-5 ─ 0
0 ─ 5
5 ─ 1010 ─ 1515 ─ 2020 ─ 2525 ─ 3030 ─ 35
0%
5%
10%
15%
20%
25%
30%
35%
CommercialBusiness
Tailwind operations
14
Headwind Kt.Tailwind Kt.
More tailwind landings in business ops
Source: NLR-ATSI/FSF
Runway length in overruns occurrences
15
LA-Business
LA-Passenger/cargo
TO-Business
TO-Passenger/cargo
0 500 1000 1500 2000 2500 3000
Average runway length (m)
A/c type depended No data on day-to-day ops
Source: NLR-ATSI
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.
16
Runway width in veeroffs occurrences
17
Business
Commercial
0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0
Average runway width (m)
Matches with runways normally used
Source: NLR-ATSI
Wheel track comparison
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Commercial a/c
5-14 m
Business a/c
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).
Demonstrated crosswinds (dry rwy)
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1950 1960 1970 1980 1990 2000 2010 20200
5
10
15
20
25
30
35
40
45
50 Business JetsPassenger aircraft
Year of certification
Cros
swin
d (k
ts)
Buss Jets average: 26 kts
Passenger a/c average: 30 kts.
Source: NLR-ATSI
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. 21
Remember there is more than factorcausing runway excursions
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Excess approach speed, Late touchdown, Delayed application wheel brakes.
Example
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....
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SANTOS DUMONT AIRPORT, Brazil
Landing overrun
Take-off overrun
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