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Use of GRIB hazard forecasts in flight planning

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Use of GRIB hazard forecasts in flight planning
Bob Lunnon, Aviation Outcomes Manager, Met Office
WAFS Science meeting, Washington, April 20th 2009
В© Crown copyright Met Office
Introductory comment
• To some, this approach to using the GRIB
hazard products might seem obvious
• However, there needs to be very effective
dialogue between the various stakeholders
(including WAFCs, flight planning companies,
airlines, regulators) for cost-effective use of the
products to be possible
• We have an opportunity to ensure that all
concerned collaborate to ensure optimum use
of the products
В© Crown copyright Met Office
Use forecast of CAT as an
example for other hazards
• We have more experience in forecasting CAT
than other hazards, and in verifying our
forecasts
• We have estimates of the “cost” of a CAT
encounter
• We have done calculations on the total cost of a
flight, including “cost” of CAT encounters
• Approach can be extended to other hazards
(Cb, icing) if costs are known
В© Crown copyright Met Office
Flying from A to B through area of
forecast high frequency of CAT
A
B
Black in centre of plot indicates area of high frequency of CAT
Dark grey in plot indicates area of moderate frequency of CAT
Light grey in plot indicates area of low frequency of CAT
This graphic could be either a map or a cross-section
(later we will assume it is a map)
В© Crown copyright Met Office
Possible strategies for avoiding
areas where forecast CAT is
above some threshold
A
B
Can in principle choose routes which tangentially touch
areas where CAT frequency is above some threshold
(with Met Office optimum route system can do this)
В© Crown copyright Met Office
Most flight planning systems consider
a network of fixed routes
B
A
Here we show only routes which realistically might be
chosen when flying from A to B
(Network of routes may be different scale to CAT areas)
В© Crown copyright Met Office
Consider direct route from A to B
A
B
Graph at bottom of plot indicates expected frequency
of CAT as aircraft flies directly from A to B
В© Crown copyright Met Office
Consider route chosen to
maximise CAT avoidance
Graph at bottom of plot indicates expected frequency
of CAT as aircraft flies from A to B along indicated route
В© Crown copyright Met Office
Compare routes
Information in graphs should be generated by
flight planning companies and fed to airlines/pilots
В© Crown copyright Met Office
Costs of CAT encounters and
CAT avoidance
If fly round light grey area, cost of CAT encounters is
low, cost of CAT avoidance is high
If fly round black area, cost of CAT encounters is
high, cost of CAT avoidance is low
It should be possible to identify CAT avoidance
strategy which minimises total cost
В© Crown copyright Met Office
CAT avoidance
CAT cost benefit diagram
1400
1200
Cost
1000
Cost of CAT
encounters
800
Cost of CAT avoidance
600
Net cost
400
200
0
Infinity
>6%
>4%
>2%
CAT avoidance strategy
Note that a very limited number of flights
were used to generate this figure
В© Crown copyright Met Office
Information needed to
generate cost-benefit graph
• Information on extra distance flown for each
avoidance strategy (from flight planning
company)
• Information on cost of extra distance flown
(from airlines)
• Information on frequency of actual CAT
encounters for each avoidance strategy (from
WAFC)(depends on accuracy of forecasts)
• Information on cost of CAT encounters (from
airlines)
В© Crown copyright Met Office
Figures used to generate
cost-benefit graph
• Study undertaken in 1990s
• Used Met Office Optimum route package to calculate
extra distance flown, and extra time to fly additional
distance
• Used then price of fuel to derive a cost
• Used verification statistics to derive frequency of CAT
encounters
• Used figures from Tom Fahey for cost of CAT encounter
• Avoiding areas of high (>6%) CAT probability was
financially “better” than no CAT avoidance
• Our forecasts have improved since then!
В© Crown copyright Met Office
Use of hazard data in airline
flight planning systems
For any route under consideration calculate time to fly,
conventional cost, fuel, as at present
For any route, calculate average forecast CAT frequency
Using data from WAFC, calculate expected frequency
of CAT encounters for all prospective routes
Derive cost of CAT encounters for all prospective routes
В© Crown copyright Met Office
Optimum routes westbound for
10/12/2008, from 5/12/2008
В© Crown copyright Met Office
Questions & answers
В© Crown copyright Met Office
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