ASSTAR User Forum #1 Rome 4th April 2006 ASAS-TN2 Second Workshop Benefit Appraisal for Oceanic Applications Dr T E Johnson, BAE Systems

page 2 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications An initial review of benefits has been conducted under ASSTAR WP1.5. For ASAS Oceanic applications this covers the following. –ATSA-ITP (Airborne Traffic Situation Awareness In Trail Procedure) –ASEP-ITP (Airborne Separation In Trail Procedure) –ASEP-ITF (Airborne Separation In Trail Follow) –SSEP-FFT (Self Separation Free Flight Track)  The applications have been evaluated for an Organised Track System (OTS) but are also suitable for use with User Preferred Routes (UPRs).  The review was purely qualitative.  Quantitative results will be available later from simulation studies.

page 3 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications Flight Efficiency  The principal benefits from ASAS Oceanic applications arise from improved flight efficiency.  A flight efficiency benefit arises because the applications allow an aircraft greater flexibility to fly at a preferred flight level and speed.  Optimum altitude for an aircraft is dependent upon fuel load.  For efficient operation, the aircraft needs to climb as fuel is burnt off.  Efficiency is enhanced if an aircraft can fly at a level to best exploit wind corridors.  Additionally, an aircraft whose speed is constrained by preceding aircraft may be able to increase its efficiency by changing levels.

page 4 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications  Oceanic applications achieve greater flexibility as follows (in ascending order) –ATSA-ITP:  Enhanced opportunity to climb or descend two flight levels.  Reduced longitudinal separation permitted for intermediate flight level. –ASEP-ITP  Further enhanced opportunity to climb or descend two flight levels.  Required longitudinal separation for intermediate flight level is less than for ATSA-ITP. –ASEP-ITF  Enhanced opportunity to climb or descend one flight level.  Reduced separation permits a greater number of aircraft to occupy their preferred level.  Improved level capacity creates more opportunities for aircraft to change levels. –SSEP-FFT  Further enhanced opportunity to climb or descend to the optimum flight level.  Even greater flexibility to select speed and flight level.

page 5 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications Improved flight efficiency leads to benefits in the form of –Reduced fuel consumption –Reduced gaseous emissions –Largely from reduced fuel consumption –Potential for increased payload –As a partial trade-off against reduced fuel consumption –Reduced contingency fuel if the maximum fuel requirement can predicted with greater certainty. –Reduced maintenance costs –Arising from reduced flight time –Reduced diversion risk (due to reduced fuel consumption) –Applies to aircraft taking off with maximum fuel load –Earlier arrival time –Predominately a non-monetary passenger benefit

page 6 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications Benefits in addition to those arising from flight efficiency –Reduced ATC provision (ASEP-ITF and SSEP-FFT)  SSEP-FFT –Substantial controller workload reduction under normal operation –Reserve levels of back-up ATC resourcing yet to be addressed –Domestic/oceanic controller transitions yet to be addressed  ASEP-ITF –Modest potential controller workload reduction for worst case scenarios –Greater potential capability to accommodate traffic growth. –Reduced turbulence  Non-monetary benefit arising from increased opportunity for flight level change –Possible safety improvements  Improvement in traffic situational awareness  Requirement for no degradation of safety, but may improve in practice.

page 7 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications Some potential benefits were discounted including … –Improved predictability  The greater utilisation of wind corridors could improve arrival times but at the expense of predictability –Increased capacity  Some of the procedures will lead to an increase in route capacity.  This will only be a benefit if the level of air traffic would otherwise be limited by the available capacity. –Flight time savings  For long haul flights, shorter flying times are unlikely to lead to scheduling efficiencies or to efficiencies in the use of aircraft and crew. –Consequential reductions in maintenance and fuel consumption have been covered as separate benefits.

page 8 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications Experimental Evaluation of Flight Efficiency Improvement  The main benefit to be evaluated by simulation is flight efficiency improvement –This can be measured as changes in fuel consumption, distance flown, time flown. –Reduction in gaseous emissions can be estimated from reductions in fuel consumption. –Measures of controller workload will be recorded.  A general issue for the determination of fuel savings in oceanic airspace is that total fuel consumption within the oceanic airspace is not entirely independent of manoeuvres prior to, or subsequent to travel within in the oceanic track segment.

page 9 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications The fuel consumption for Aircraft 1 may be less within the oceanic track segment but over the whole journey the fuel consumption for Aircraft 2 is less. Comparisons should be made from a common start and end point.

page 10 ASSTAR User Forum #1  Flight efficiency will be assessed by fast time simulations –7 scenarios will be evaluated for different traffic levels.  4 ASAS procedures  3 reference scenarios –‘worst case’ (no flight level changes within oceanic track) –‘best case’ (unrestricted flight level and speed changes) –‘benchmark case’ (non-ASAS, current procedural control, optimal use of level changes)

page 11 ASSTAR User Forum #1 Benefit Appraisal for Oceanic Applications  Results from ASSTAR fast time simulations will be available by June 2006  Results from ASSTAR real time simulations will be available by August 2007 –Recent work commissioned by NASA gives some indications of the levels of benefits that can be expected from reduced separations.  Almira R. Williams “ Benefits Assessment of Reduced Separations in North Atlantic Organised Track System” CSSI Inc. Advanced Programs, Prepared for NASA Glenn Research Centre, p_NAtlantic_OTS_Final_Report_2005Oct3.pdf p_NAtlantic_OTS_Final_Report_2005Oct3.pdf

page 12 ASSTAR User Forum #1 Summary  A review has been undertaken of ASAS oceanic applications.  Some potential benefits identified prior to the review were found to be non-applicable.  The principal monetary benefits have been identified as arising from flight efficiency improvements.  Flight efficiency improvements will be evaluated by simulation methods.

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